MODEL RDG-24 USER MANUAL
Contents
1. Risc bat A batch file demonstrating the command line parameters of RISCTerm exe RISCTerm exe A dumb terminal type communication program designed for RS422 485 operation Used primarily with Remote Data Acquisition Pods and our RS422 485 serial communication product line Can be used to say hello to an installed modem RISCTerm stands for Really Incredibly Simple Communications TERMinal Page 2 4 Manual MRDG 24 C2c Installing the Pod The RDG 24 enclosure is an easily mounted steel enclosure Outside dimensions of the enclosure are 8 5 long by 5 25 wide by 2 high The cover is secured to the body by four Phillips head screws Four threaded bosses inside the enclosure provide for mounting the printed circuit card assemblies The enclosure has a notch at one end for external power wiring and a deeper notch at the other end for input and output wiring Electrical power RS485 connections to the pod are made at Terminal Board TBI Terminal markings and their functions are as follows ISO GND and ISO PWR RX and RX TX and TX EXV PWR and GND Manual MRDG 24 C2c This is the power connection from the computer s 12VDC supply via telephone cable on the RS485 network or from a central power supply This powers the isolator section and is independent of local power The voltage level can be from 7 5 VDC to 35 VDC An on board voltage regulator regulates the power to 5 VDC RDG 24 will require only about 7 mA of cur2. 500 Hz Digital inputs of up to 50V may be read individually or in 8 bit bytes or in 24 bit word groups There are also digital software counters on each input Selectable edges can be counted for up to 65 535 transitions These counters support Read and Reset commands Moreover change of state flags can be set on any enabled input bits and can be read via the serial port This is particularly useful in applications where it s necessary to detect contact closures or openings This change of state detection capability is enabled on a bit by bit basis for all bits programmed for input Digital outputs may be programmed individually or in 8 bit bytes or in 24 bit words These outputs may be latched pulsed or set to free run for a prescribed period of time The digital output drivers are open collector circuits that have 350 mA drive capability at a logic low The unit can comply with up to 50 VDC voltage supplied by you With no external voltage EXV supplied the outputs are pulled up by a 10 KQ resistor to 5 VDC The built in watchdog timer resets the pod if for some unexpected reason the microcontroller hangs up Data collected by the pod can be stored in local RAM and accessed later through the computer s serial port This facilitates a stand alone pod mode of operation Page 1 2 Manual MRDG 24 C2c Specifications Serial Communications Interface Serial Port Opto isolated Matlabs type LTC491 Transmitter Receiver Compatible
3. 80 C Temperature De rating Ambient temperature de rating must be considered based on the power level applied When 7 5VDC is applied the temperature rise inside the enclosure is 7 3 C above the ambient temperature The equation to determine maximum temperature de rating is Viar 120 lt 22 5 0 2 T Where T is the ambient temperature in C and V 7 _ 120 18 the voltage at which the integral voltage regulator junction temperature will rise to a temperature of 120 C Note The junction temperature is rated to 150 C maximum For example at an ambient temperature of 25 C the voltage V can be up to 18 4V At an ambient temperature of 100 F 37 8 C the voltage V can be up to 16 6V e Storage Temperature Range 50 C to 120 C e Humidity 5 to 95 RH non condensing e Size Enclosure 8 5 long by 5 25 wide by 2 high Power Required Power can be applied from the computer s 12VDC power supply for the opto isolated section via the serial communication cable and froma local power supply for the rest of the unit e Opto Isolated Section 7 5 to 25 VDC 40 mA Note Due to the small amount of current required voltage drop in the communication cable is not significant Local Power PWR 7 5 to 16 VDC 150mA See box below If the local power supply has an output voltage greater than 16VDC you can install a zener diode in series with the supply voltage The voltage rating of the zener d
4. Output Voltage unloaded Driver Output Voltage loaded LD and LDGND Driver Output Resistance 50W Driver Output Short Circuit Current 150 mA Driver Output Rise Time unit interval Receiver Sensitivity 200 mV Receiver Common Mode Voltage Range 7V Receiver Input Resistance Table A 2 RS422 Specification Summary To prevent signal reflections in the cable and to improve noise rejection in both the RS422 and RS485 mode the receiver end of the cable should be terminated with a resistance equal to the characteristic impedance ofthe cable An exception to this is the case where the line is driven by an RS422 driver that is never tri stated or disconnected from the line In this case the driver provides a low internal impedance that terminates the line at that end Page A 2 Manual MRDG 24 C2c RS485 Data Transmission The RS485 Standard allows a balanced transmission line to be shared in a party line mode As many as 32 driver receiver pairs can share a two wire party line network Many characteristics of the drivers and receivers are the same as in the RS422 Standard One difference is that the common mode voltage limit is extended and is 12V to 7V Since any driver can be disconnected or tri stated from the line it must withstand this common mode voltage range while in the tristate condition The following illustration shows a typical multidrop or party line network Note that the transmission line is terminated on
5. and their functions are as follows JP2 JP3 and JP4 Normally these jumpers should be in the ISL position If you wish to by pass the opto isolators then you can move these jumpers to the ISL position Digital Input Output Pin Connections Digital input and output connections can be made in any of three ways a at Euro style screw terminals TB2 TB3 TB4 and TBS or b at 50 pin keyed male insulation displacement type ribbon cable connector J2 or c at 37 pin male sub D connector J1 Screw Terminal Connections Digital I O connection points at the screw terminal connectors are as marked on the printed circuit board at terminals TB2 and TB3 Bit locations are numbered 00 through 23 decimal Note also that a terminal labeled XRST is provided at TB5 for Reset signals to the microprocessor The other terminals on TB5 and TB4 provide ground returns for the I O signals Manual MRDG 24 C2c Page 2 7 RDG 24 Manual 50 Pin Connector Connector pin assignments for the 50 pin connector are listed below Note that alternate wires in the ribbon cable will be connected to ground This provides means to isolate the digital signals from each other in the cabling 1 013 VOU Table 2 1 50 Pin Connector Assignments Page 2 8 Manual MRDG 24 C2c 37 Pin Connector J1 Optional Connector pin assignments for the 37 pin connector are listed below Note that since this connector would normally not mate with a ribbon cable alternate
6. both ends of the line but not at drop points in the middle of the line TERMINATION RESISTORS AT BOTH ENDS ONLY TX ENABLE TX ENABLE RX ENABLE RX ENABLE TX ENABLE TX ENABLE RX ENABLE 9 P RX ENABLE Figure A 1 Typical RS485 Two Wire Multidrop Network Manual MRDG 24 C2c Page A 3 RDG 24 Manual Page A 4 Manual MRDG 24 C2c Customer Comments If you experience any problems with this manual or just want to give us some feedback please email usat manuals accesioproducts com Please detail any errors you find and include your mailing address so that we can send you any manual updates VO ACCES I O PRODUCTS INC 10623 Roselle Street San Diego CA 92121 Tel 619 550 9559 FAX 619 550 7322 www accesioproducts com
7. ground pins are not provided there would not be enough pins anyway Also note thatthere is provision for external Reset for a Timer signal and for Interrupts 0 and 1 V O 06 Gnd VO 10 Gnd VO 16 EXV VO 17 EXV Gnd Table 2 2 37 Pin Connector Assignments m m Re Re m m m m m m Units that are marked for CE European Certification are installed in a NEMA 4 enclosure rather than the T BOX metal enclosure referred to earlier Further to ensure that there is minimum susceptibility to EMI and minimum radiation it is important that there be a positive chassis ground Proper EMI cabling techniques cable connected to chassis ground at the aperture tristed pair wiring and in extreme cases ferrite level of EMI protection must be used CE marked versions of RDG 24 meet the requirements of EN50081 1 1992 Emissions EN50082 1 1992 Immunity and EN60950 1992 Safety Manual MRDG 24 C2c Page 2 9 RDG 24 Manual Page 2 10 Manual MRDG 24 C2c Chapter 3 Software General You received ASCII based software on CD for use with RDG 24 ASCII programming permits you to write applications in any high level language that supports ASCI string functions The communication protocol has two forms addressed andnon addressed Non addressed protocol can be used when only one RDG 24 is in use If more than one RDG 24 is in use you must use addressed protocol The difference is that an address command is sent to enable the specific p
8. A number which must appear on the outer label of the return package All units components should be properly packed for handling and returned with freight prepaid to the ACCES designated Service Center and will be returned to the customer s user s site freight prepaid and invoiced Coverage First Three Years Returned unit part will be repaired and or replaced at ACCES option with no charge for labor or parts not excluded by warranty Warranty commences with equipment shipment Following Years Throughout your equipment s lifetime ACCES stands ready to provide on site or in plant service at reasonable rates similar to those of other manufacturers in the industry Equipment Not Manufactured by ACCES Equipment provided but not manufactured by ACCES is warranted and will be repaired according to the terms and conditions of the respective equipment manufacturer s warranty General Under this Warranty liability of ACCES is limited to replacing repairing or issuing credit at ACCES discretion for any products which are proved to be defective during the warranty period Inno case is ACCES liable for consequential or special damage arriving from use or misuse of our product The customer is responsible for all charges caused by modifications or additions to ACCES equipment not approved in writing by ACCES or ifin ACCES opinion the equipment has been subjected to abnormal use Abnormal use for purposes of this warranty is defined as any use to
9. A xx Program the currently selected pod to respond at address xx This command changes the pod s address to xx Ifthe new address is 00 the pod will be placed into non addressed mode If the new address is not 00 the pod will not respond to further communications until a valid address command is issued Hex numbers 00 FF are considered valid addresses The R specification allows only 32 drops on the line so some addresses may be unused The new pod address is saved in EEPROM and will be used even after power down until the next A xx command is issued Note that if the new address is not 00 i e the pod is configured to be in addressed mode it is necessary to issue an address command to the pod at the new address before it will respond The pod returns a message containing the pod number as confirmation Example Set the pod address to 01 SEND A 01 RECEIVE Pod 01 CR Set the pod address to F3 SEND A F3 RECEIVE Pod F3 CR Take the pod out of addressed mode SEND A 00 RECEIVE Pod 00 CR Page 3 12 Manual MRDG 24 C2c Read and Store Digital Input Data FASTDATAL Read digital bits 0 7 as fast as possible FASTDATAM Read digital bits 8 F as fast as possible FASTDATAH Read digital bits 10 17 as fast as possible These commands read the respective byte of digital input data and store it in RAM at the fastest possible rate 21 microseconds between samples The commands will store as much data as the pod can hold RA
10. Base SCXXXX Set Time Base with Output Synchronization This function sets the pod global timebase which is used in all time sensitive operations Valid values range from 039A to FFFF Any invalid value will result in the pod default timebase of 2400 10ms 100Hz 039A corresponds to 1 KHz 2400 is 100Hz and the longest timebase of FFFF corresponds to 14Hz 11 059 200 Hz 12 timebase Hz rate of time base The SCxxxx variant sets the timebase as normal then causes all free run and pulse outputs to change on the next timebase tick Examples Program the RDG 24 to a Imsec timebase SEND S039A RECEIVE CR Program the RDG 24 to a 50msec timebase and synchronize outputs SEND SC4800 RECEIVE CR Note The timebase configured is stored in EEPROM on the pod and will be used as the default power on timebase The factory default timebase 100Hz can be restored by sending S0000 to the pod Application Note If it is necessary to synchronize free running outputs the SCxxxx command will assistin this First configure all desired free run bits as outputs Then initialize each bit as free run using the fxx xx command Now by issuing an SCxxxx command synchronize all the free run outputs to toggle on the next time base tick Now all free run outputs with the same time duration will toggle on the same tick 20usec skew max per byte Manual MRDG 24 C2c Page 3 3 RDG 24 Manual Configure Bits as Input or Output Mixx Confi
11. M size 1KByte Typically this is 7Kbytes of data however a 32k RAM version is optionally available which would provide 31Kbytes of data storage Once the data has been stored it is dumped to the serial port The data is formatted into 3 byte chunks followed by a space xxxxxx xxx etc There are no carriage returns until the last byte has been sent All normal pod activities parsing commands receiving commands pulse output countdowns free run generation COST detect etc STOP until the serial data is done transmitting NOTHING else works until the data has been dumped Re send Data D This will dump the last stored historical data to the serial port Data can be resent by issuing a D command This will dump the last stored historical data to the serial port and can be used for example if line noise or similar problems are suspected This command should only be used after FASTDATAL FASTDATAM or FASTDATAH have been issued because random data fills the buffer until one of these commands acquire data The format of the data is identical to the FASTDATAx commands See the previous description of the FASTDATAx command for more information about the format and length of returned data Example Resend the data buffer SEND D RECEIVE XXXXXX XXXXXX XXXXXX XXXXXX for size of buffer Enter a New Program PROGRAM This command initiates transfer of a new program to the RDG 24 This command should be used carefully If you acci
12. O ACCES I O PRODUCTS INC 10623 Roselle Street San Diego CA 92121 TEL 858 550 9559 FAX 858 550 7322 MODEL RDG 24 USER MANUAL FILE MRDG 24 C2c Notice The information in this document is provided for reference only ACCES does not assume any liability arising out ofthe application or use of the information or products described herein This document may contain or reference information and products protected by copyrights or patents and does not convey any license under the patent rights of ACCES nor the rights of others IBM PC PC XT and PC AT are registered trademarks of the International Business Machines Corporation Printed in USA Copyright 1995 by ACCES VO Products Inc 10623 Roselle Street San Diego CA 92121 All rights reserved Page iii Warranty Prior to shipment ACCES equipment is thoroughly inspected and tested to applicable specifications However should equipment failure occur ACCES assures its customers that prompt service and support will be available All equipment originally manufactured by ACCES which is found to be defective will be repaired or replaced subject to the following considerations Terms and Conditions If a unit is suspected of failure contact ACCES Customer Service department Be prepared to give the unit model number serial number and a description of the failure symptom s We may suggest some simple tests to confirm the failure We will assign a Return Material Authorization RM
13. Ox Set bit x hi or low Oxx Set bit xx hi or low Ox txx Pulse bit x hi or low for time xx Oxxtxx Pulse bit xx hi or low for time xx Olxx Write to bits 0 7 Omxx Write to bits 8 F Ohxx Write to bits 10 17 bxtxx Identical to Oxtxx bxxtxx Identical to Oxxtxx These commands write outputs to digital bits Any attempt to write to a bit configured as input will fail Writing to a byte or word wherein some bits are input and some are output will cause the output latches to change to the new value but the bits which are inputs will not output the value until unless they are placed in output mode Single bit commands will return an error 4 if an attempt is made to write to a bit configured as an input Writing a one to a port asserts the pull down Writing a zero de asserts the pull down Therefore if the factory installed 45V pull up is installed writing a one will cause zero volts to be at the connector and writing a zero will cause 5 volts to be asserted If the factory installed pull up has been removed the user supplied pull up will be asserted Manual MRDG 24 C2c Page 3 5 RDG 24 Manual Pulsing a bit high or low uses the currently configured timebase The bit will be set to 5V or OV for a period equal to xx time ticks where one time tick occurs every timebase So if the default timebase of 2400 3916 dec or 100Hz is currently selected and 32 hex was specified for a pulse duration the bit will pulse high or l
14. bol designates either a or a All commands are terminated with CR the ASCII character 13 Wherever xx is used to designate a bit number only 00 17 hex are valid Commands are not case sensitive i e upper or lower case letters may be used The symbol means zero or more valid characters total msg length lt 255 decimal wmoene ges Manual MRDG 24 C2c Page 3 1 RDG 24 Manual Command List SXXXX Set a new timebase 039A lt xxxx lt FFFF CR Scxxxx Set a new timebase and reset all free run and pulse DOs CR Mixx Configure bits 00 07 as input output O in 1 out CR Mmxx Configure bits 08 OF as input output 0 in 1 out CR Mhxx Configure bits 10 17 as input output 0 in 1 out CR I Read all 24 digital bits XXXXXXCR Ixx Read a single digital bit 00 lt xx lt 17 bCR IL Read digital bits 00 07 xxCR IM Read digital bits 08 0F xxCR IH Read digital bits 10 17 xxCR OXXXXXX Output all 24 digital bits CR Ox Output either high or low on bit x CR Oxx Output either high or low on bit xx CR Ox xx Output either high or low on bit x for time xx CR Oxx xx Output either high or low on bit xx for time xx CR OLxx Output xx on bits 00 07 CR OMxx Output xx on bits 08 OF CR OHxx Output xx on bits 10 17 CR Oxx xx Output either high or low on bit xx for time xx CR Fxx xx Set Digital Output xx to free run with period xx CR Y Read digital input Change Of State bit and clear bit Y or N TLxx Set bit 00 07 Mask for COST bit f
15. ced by the driver appears across a pair of wires A balanced line driver will produce a differential voltage from 2 to 6 volts across its output terminals A balanced line driver can also have an input enable signal that connects the driver to its output terminals If the enable signal is OFF the driver is disconnected from the transmission line This disconnected or disabled condition is usually referred to as the tristate condition and represents a high impedance RS485 drivers must have this control capability RS422 drivers may have this control but it is not always required Manual MRDG 24 C2c Page A 1 RDG 24 Manual A balanced differential line receiver senses the voltage state ofthe transmission line across the two signal input lines Ifthe differential input voltage is greater than 200 mV the receiver will provide a specific logic state on its output Ifthe differential voltage input is less than 200 mV the receiver will provide the opposite logic state on its output A maximum operating voltage range is from 6V to 6V allows for voltage attenuation that can occur on long transmission cables A maximum common mode voltage rating of 7V provides good noise immunity from voltages induced on the twisted pair lines The signal ground line connection is necessary in order to keep the common mode voltage within that range The circuit may operate without the ground connection but may not be reliable Parameter Driver
16. dentally issue a PROGRAM command ESC ASCII 27 will restart the pod as if power had been reset This feature is designed to allow ACCES to provide field upgrades to the RDG 24 firmware and for advanced users the opportunity to customize the firmware in the pod Documentation relating to use of this command is provided or is available separately for a small fee Manual MRDG 24 C2c Page 3 13 RDG 24 Manual Error Codes The following error codes can be returned from the pod 1 Invalid channel number too large or not a number All channel numbers must be between 00 and 17 in hex 0 24 decimal 3 Improper Syntax Not enough parameters is the usual culprit 4 Channel number is invalid for this task For example if you try to output to a bit that is set as an input bit that will cause this error 9 Parity error This occurs when some part of the received data contains a parity or framing error Additionally several full text error codes are returned All begin with Error and are useful when using a terminal to program the pod Error Unrecognized Command command received CR This occurs ifthe command is not recognized Error Command not fully recognized Command received CR This occurs if the first letter ofthe command is valid but the remaining letters are not Error Address command must be CR terminated CR This occurs if the address command xx CR has extra characters between the pod number and t
17. dress Communication uses a master slave protocol wherein the pod talks only if questioned by the computer A type 8031 microcontroller with 8x8K RAM 8x8K non volatile EEPROM anda watchdog timer circuit gives RDG 24 the capability and versatility expected from a modern distributed control system To accommodate special programs the RAM and EEPROM can each be expanded to 8x32K The unit contains CMOS low power circuitry an optically isolatedreceiver transmitter and power conditioners for local and external isolated power It can operate at baud rates up to 57 6 Kbaud and distances up to 4000 feet with low attenuation twisted pair cabling All programming of RDG 24 is in ASCH based software ASCII based programming permits you to write applications in any high level language that supports ASCII string functions and you can use ACCES R series pods with virtually any computer Manual MRDG 24 C2c Page 1 1 RDG 24 Manual The module or pod address is programmable from 00 to FF hex and whatever address is assigned is stored in EEPROM and used as the default address at the next Power ON Similarly the baud rate is programmable for 1200 2400 4800 9600 14400 19200 28800 and 57600 The address is stored in EEPROM and used as default at the next Power ON The time base used in all time relevant operations is also software selectable between a Digital input sample rate from 14 Hz to 1 KHz b Digital output square wave pulse from 7 Hz to
18. erating systems and still have full access to the hardware registers The DLL is used exactly like any other DLL so it is compatible with any language capable of using 32 bit DLLs Consult the manuals provided with your language s compiler for information on using DLLs in your specific environment VBACCES This directory contains sixteen bit DLL drivers for use with VisualBASIC 3 0 and Windows 3 1 only These drivers provide four functions similar to the ACCES32 DLL However this DLL is only compatible with 16 bit executables Migration from 16 bit to 32 bit is simplified because of the similarity between VBACCES and ACCES32 PCI This directory contains PCI bus specific programs and information If you are not using a PCI card this directory will not be installed SOURCE A utility program is provided with source code you can use to determine allocated resources at run time from your own programs in DOS PCIFind exe A utility for DOS and Windows to determine what base addresses and IRQs are allocated to installed PCI cards This program runs two versions depending on the operating system Windows 95 98 NT displays a GUI interface and modifies the registry When run from DOS or Windows3 x a text interface is used For information about the format of the registry key consult the card specific samples provided with the hardware In Windows NT NTioPCLSYS runs each time the computer is booted thereby refreshing the registry as PCI hardware i
19. gital input active state on bit xx These commands allow you to set whether a rising or falling edge will increment the digital input counter i e if all bits are set to rising edge the digital input counter for any given bit will increment each time a rising edge is detected is rising edge is falling edge Examples Set bit 1 to rising edge active SEND D1 or SEND D01 RECEIVE CR Set bit 17 to falling edge active Note Page 3 8 SEND RECEIVE D17 CR The digital input counters are read with the cxx command and reset with the rxx command Manual MRDG 24 C2c Read Digital Input Counter amp Read Time Left on Pulse or Free Run Output CXX Read digital input counter xx CXX Read pulse or free run status and reload counters This command performs two duties depending on whether the bit is configured as input or output If the bit is configured as an input this command will read how many times bit xx has changed to its active state as configured with dx or dxx since the last reset command rxx If this bit is configured as an output this command will indicate how much time in time base units remains in a pulse output or free run output before the pulse terminates If the output is configured as free run it also returns what period is programmed into the output counter Input counters are configured as 16 bit counters Counter content is provided most significant bit firs
20. gital input number 3 SEND r03 RECEIVE CR Stop free run digital output on output number 14 SEND r14 RECEIVE CR Read Firmware Revision Number V Read the firmware revision number This command is used to read the version of firmware installed in the pod It returns X XX CR Example Read the RDG 24 version number SEND V RECEIVE 1 00 CR Note The H command returns the version number along with other information Resend Last Response n Resend last response This command will cause the pod to return the same thing it just sent This command works for all responses less than 255 characters in length Normally this command is used ifthe host detected a parity or other line fault while receiving data and needs the data to be sent a second time The n command may be repeated Example Assuming the last command was I ask pod to resend last response SEND n RECEIVE FFFFFF CR or whatever the data was Note This command may not be used for the FASTDATA L M or H commands as they exceed the 255 character limit Use the D command to perform the same task for these three commands Page 3 10 Manual MRDG 24 C2c Hello Message H Hello message Any string of characters starting with H will be interpreted as this command H CR alone is also acceptable The return from this command takes the form without the quotes Pod aa RDG 24 Rev rr Firmware Ver x xx ACCES aa is the pod address IT is the
21. gure bits 0 7 as input output Mmxx Configure bits 8 F as input output Mhxx Configure bits 10 17 as input output These functions program on a bit by bit basis the digital bits as input or output in groups of eight The MLxx command control input output on bits 0 7 MMxx control bits 8 F and MHxx controls bits 10 17 A zero in any bit position of the xx control byte designates the corresponding bit as an input Conversely a one designates a bit to be configured as an output Note Any bit configured as an output can still be read as an input if the current value output is a one Examples Program even bits as outputs and odd bits as inputs SEND MLAA RECEIVE CR SEND MMAA RECEIVE CR SEND MHAA RECEIVE CR Program bits 0 7 as input and bits 8 F as output SEND ML00 RECEIVE CR SEND MMFF RECEIVE CR Read Digital Inputs I Read 24 bits Ixx Read bit number xx IL Read bits 00 07 IM Read bits 08 0F IH Read bits 10 17 These commands read the digital input bits from the pod All byte or word wide responses are sent most significant nibble first Page 3 4 Manual MRDG 24 C2c Examples Read ALL 24 bits SEND I RECEIVE 7 FFFFFF CR Read only bit 17 23 decimal the highest bit on the card SEND 117 RECEIVE 1 CR Read only bit 2 SEND 102 RECEIVE 1 CR Read bits 8 F SEND IM RECEIVE FF CR Write Digital Outputs OXXXXXX Write to all 24 digital output bits
22. hardware revision such as BI xxx is the software revision such as 1 00 Example Read the greeting message SEND Hello RECEIVE Pod 00 RDG 24 Rev B1 Firmware Ver 1 00 ACCES cr Set a New Baud Rate When Shipped by Acces the Baud Rate Is Set at 9600 BAUD xxx Program the pod with a new baud rate This command sets the pod to communicate at a new baud rate The parameter passed xxx is slightly unusual Each x is the same digit from the following table Code Baud Rate 0 1200 1 2400 2 4800 3 9600 4 100 5 19200 6 28800 57600 Therefore valid values for the command s xxx are 000 111 222 333 444 555 666 or 777 The pod returns a message indicating it will comply The message is sent in the old baud rate not the new one Once the message is transmitted the pod changes to the new baud rate The new baud rate is stored in EEPROM and will be used even after power reset until the next BAUD xxx command is issued Manual MRDG 24 C2c Page 3 11 RDG 24 Manual Example Set the pod to 19200 baud SEND BAUD 555 RECEIVE Baud 05 CR Set the pod to 9600 baud SEND BAUD 333 RECEIVE Baud 03 CR Note There is an undocumented Code 7 which selects 57600 baud This code can be used for testing but only with short cables Use of this code is not recommended due to possible difficulty with character drop out and other line noise problems Program the Pod Address
23. he CR Page 3 14 Manual MRDG 24 C2c Appendix A Application Considerations Introduction Working with RS422 and RS485 devices is not much different from working with standard RS232 serial devices and these two standards overcome deficiencies in the RS232 standard First the cable length between two RS232 devices must be short less than 50 feet at 9600 baud Second many RS232 errors are the result of noise induced on the cables The RS422 standard permits cable lengths up to 5000 feet and because it operates in the differential mode it is more immune to induced noise Connections between two RS422 devices with CTS ignored should be as follows Device 1 Device 2 Signal Pin No Signal Pin No Gnd 7 Gnd 7 TX 24 RX 12 TX 25 RX 13 RX 12 TX 24 xo loo m Table A 1 Connections Between Two RS422 Devices A third deficiency of RS232 is that more than two devices cannot share the same cable This is also true for RS422 but RS485 offers all the benefits of RS422 plus allows up to 32 devices to share the same twisted pairs An exception to the foregoing is that multiple RS422 devices can share a single cable if only one will talk and the others will all receive Balanced Differential Signals The reason that RS422 and RS485 devices can drive longer lines with more noise immunity than RS232 devices is that a balanced differential drive method is used Ina balanced differential system the voltage produ
24. iode V should be equal to V 16 where V is the power supply voltage The power rating of the zener diode should be gt V x 0 12 watts Thus for example a 24VDC power supply would require using an 8 2V zener diode with a power rating of 8 2 x 0 12 1 watt Manual MRDG 24 C2c Page 1 5 RDG 24 Manual DIGITAL Page 1 6 INPUT LATCHES bE 1 1 1 OUTPUT OUTPUT L DRIVERS LATCHES 1 1 1 1 lt btt DIGITAL MULTIPLEXER CTRL AA Figure 1 2 Block Diagram XTAL WATCHDOG osc CIRCUIT TYPE 8021 OPTO RS485 PORT MICRO ISOLATORS CONTROLLER z SRAM EEPROM POWER a i INPUT 1 1 1 1 1 1 OPTIONAL OPTIONAL 1 1 EXPANSION 1 EXPANSION 1 1 i 1 1 Manual MRDG 24 C2c Chapter 2 Installation The software provided with this card is contained on either one CD or multiple diskettes and must be installed onto your hard disk prior to use To do this perform the following steps as appropriate for your software format and operating system Substitute the appropriate drive letter for your CD ROM or disk drive where you see d or a respectively in the examples below CD Installation DOS WIN3 x a Place the CD into your CD ROM drive b Type LJE to change the active drive to the CD ROM drive c Type JASJE to run the install program d Follow the on screen prompts to insta
25. lag I change will set COST CR TMxx Set bit 08 OF Mask for COST bit flag CR THxx Set bit 10 17 Mask for COST bit flag CR Dx Set digital input active state high or low on bit x CR Dxx Set digital input active state high or low on bit xx CR Cxx Read digital input xx counter counts each active pulse XxxxCR or Read pulse free run output xx counter and reload value xxxxCR Rxx Reset digital input counter xx to 0000 CR Rall Reset all digital input counters to 0000 CR V Read the Firmware version number x xxCR N Resend last response varies H Greeting message copyright firmware version number varies BAUD xxx Set new baud rate Each x is code number for new baud Baud 0x POD xx Set pod address to xx varies PROGRAM Begin process of uploading custom program to pod special D Download historical storage of digital input data again varies FASTDATAL Acquire bits 0 7 as fast as possible then display varies FASTDATAM Acquire bits 8 F as fast as possible then display varies FASTDATAH Acquire bits 10 17 as fast as possible then display varies Ixx Address Select Command Selects the POD at address xx CR for communication Page 3 2 Manual MRDG 24 C2c Command Functions The following paragraphs give details of the command functions describe what the commands cause and give examples Please note that all commands have an acknowledgment response You must wait for a response from a command before sending another command Set Time Base SXXXX Set Time
26. les Table 2 1 50 Pin Connector Assignments 0 0 ks 2 8 Table 2 2 37 Pin Connector Assignments 0 aaa ks 2 9 Table A 1 Connections Between Two RS422 Devices ks A 1 Table A 2 RS422 Specification Summary ks A 2 Page vi Chapter 1 Introduction Features Opto Isolated RS485 Serial Interface to Host Computer 24 Bit Digital I O Programmable Bit by Bit in 8 Bit Bytes or in 24 Bit Words Digital Input and Output Voltages up to SOVDC Open Collector Digital Outputs for Loads up to 350mA Protective Steel Enclosure Type 8031 Microcontroller with 8K x 8 RAM and 8K x 8 EEPROM 32K x 8 optional All Programming in Software No Switches to Set Jumper to Set 2 Wire or 4 Wire modes and Jumpers 3 to By Pass Opto Isolators if Desired 16 Bit Digital Input Software Counters Change of State Flag Readable via the Serial Port Digital Outputs May Be Either Level or Pulse Description RDG 24 is an intelligent 24 bit parallel digital I O to computer interface unit Communication with the host computer is via EIA RS485 full or half duplex serial communications protocol ASCII based command response protocol permits communication with virtually any computer system RDG 24 is one of a series of remote intelligent pods called the REMOTE ACCES Series As many as 32 REMOTE ACCES Series pods or other RS485 devices may be connected on a single two or four wire multidrop RS485 network Each unit has a unique ad
27. ll the software for this card WIN95 98 NT a Place the CD into your CD ROM drive b The CD should automatically run the install program after 30 seconds Ifthe install program does not run click START RUN and type d install click OK or press tel C Follow the on screen prompts to install the software for this card 3 5 Inch Diskette Installation As with any software package you should make backup copies for everyday use and store your original master diskettes in a safe location The easiest way to make a backup copy is to use the DOS DISKCOPY utility In a single drive system the command is gasa A e You will need to swap disks as requested by the system In a two disk system the command is gasa A e This will copy the contents of the master disk in drive A to the backup disk in drive B Manual MRDG 24 C2c Page 2 1 RDG 24 Manual To copy the files on the master diskette to your hard disk perform the following steps a Place the master diskette into a floppy drive b Change the active drive to the drive that has the diskette installed For example if the diskette is in drive A type AL Jie c Type CUNJ s Ja itJeve and follow the on screen prompts Directories Created on the Hard Disk The installation process will create several directories on your hard disk If you accept the installation defaults the following structure will exist CARDNAME Root or base directory containing the SETUP EXE setup p
28. nual Digital Outputs Number Up to 24 Can be programmed on a bit by bit basis on an 8 bit byte basis or on a 24 bit word basis In this latter case there would be no capability for digital inputs The inputs would read back the output value only Type Outputs can be latched pulsed or setto free run for a prescribed period of time Pulsed outputs are square wave and programmable from 7 Hz to 500 Hz e High Level Output Voltage Open Collector compliance with up to 50VDC With no external voltage EXV supplied the outputs are pulled up by a 10 KQ resistor to 5 VDC Logic Low Output Current 350 mA maximum See note below Inductive suppression diode included in the each circuit Note Maximum allowable current per output bit is 350 mA but for each six bit group there is a maximum cumulative total of 650 mA Output groups are bits 0 5 6 11 12 17 and 18 23 decimal g2 TB5 TB3 CI Gra JP2 XRST O JP GND O 080 A o 5 32K en a FDX O O DA SA ist O Iso GND El a ASLI Dliso pwr a a JP4 ISL O CJ JP3 Sr NO Rx CI O ls Tx a O e Tx o NG Ga EXV CI O O Ppwr m O eno a NO Cl NO O GND gt B4 Figure 1 1 Connecting External Voltage EXV Page 1 4 Manual MRDG 24 C2c Environmental e Operating Temperature Range 0 C to 65 C Optional 40 to
29. od The address command is only sent once during communication between the pod and the host computer It enables communication with that specific pod and disables all other devices on the network Command Structure All communication must be 7 data bits even parity 1 stop bit All numbers sent to or received from the pod are in hexadecimal form The factory default baud rate is 9600 Baud The pod is considered to be in addressed mode any time its pod address is not 00 The factory default pod address is 00 non addressed mode Addressed Mode The address select command must be issued before any other command to the addressed pod The address command is as follows Ixx CR where xx is the pod address from 01 to FF hex and CR is Carriage Return ASCII character 13 The pod responds with either xxN CR or xx Y CR if an input change of state has occurred on enabled bits since the last Y or address command Once the address select command has been issued all further commands other than a new address select will be executed by the selected pod The addressed mode is required when using more than one pod Non Addressed Mode When there s only one pod connected no address select command is needed You can merely issue commands listed in the following table Terminology used is as follows The single lower case letter x designates any valid hex digit 0 F The single lower case letter b designates either a 1 or 0 The sym
30. ow for 50 counts or one half second 50x 10ms 500ms half a second Examples Write a one to bit 13 set output to zero volts assert the pull down SEND O13 RECEIVE CR Write a zero to bit 2 set output to 5V or user pull up SEND O2 or SEND 002 RECEIVE CR Write zeros to bits 0 7 SEND OL00 RECEIVE CR Write zeros to every odd bit SEND OAAAAAA RECEIVE CR Cause bit 7 to pulse to 0 Volts for 20ms assuming S039A was issued SEND 07 14 RECEIVE CR Write zeros to bits 0 9 13 17 and ones on all other bits SEND 007FC00 RECEIVE CR Page 3 6 Manual MRDG 24 C2c Generate a Square Wave Output fxx xx Produce a free running square wave on bit xx with period xx This function will cause bit xx to change state every xx timebase units effectively generating a square wave with period xx or frequency 1 div xx 2 Examples Start a 1Hz square wave on bit 2 Bit two must be configured as output using ML such as ML02 Also the timebase is assumed to have been configured to the default 2400 or 10ms using S2400 or S0000 SEND f02 32 RECEIVE CR Note It is possible to synchronize the starting edges of any free running outputs by following the procedure outlined in the application note of the Set Timebase command SCxxxx Read Change of State Y Read COST bit The pod can set a change of state flag for any input that has been configured to do so This command will read and then reset tha
31. rent and thus any voltage drop of computer power will be inconsequential If separate power is not available then with some loss of isolation these terminals can be jumpered to the local power terminals These are the differential receive inputs for four wire RS485 communications If two wire connection is to be used install jumpers from RX to TX and from RX to TX These are the differential transmit outputs for four wire RS485 communications If two wire connection is to be used install jumpers as described above This terminal is for the application power or the voltage level to which digital inputs and outputs are connected through the loads or external signal sources Open collector Darlington amplifiers are used at the outputs Inductive suppression diodes are included and the application power level can be as high as 50 VDC These terminals can be used to apply power to the pod from a local power supply If a local power supply is used the voltage can be anywhere in the range from 7 5 VDC to 16 VDC Higher local power can be used 24 VDC for example if an external zener diode is used to reduce the voltage applied to the RDG 24 See the Specification section of this manual to determine the zener diode power rating required Page 2 5 RDG 24 Manual Figure 2 1 Option Selection Map Page 2 6 Manual MRDG 24 C2c There are three jumper locations on the card Locations are as shown on the Option Selection Map
32. rogram used to help you configure jumpers and calibrate the card DOS PSAMPLES A subdirectory of CARDNAME that contains Pascal samples DOS CSAMPLES A subdirectory of CARDNAME that contains C samples Win32 language Subdirectories containing samples for Win95 98 and NT WinRisc exe A Windows dumb terminal type communication program designed for RS422 485 operation Used primarily with Remote Data Acquisition Pods and our RS422 485 serial communication product line Can be used to say hello to an installed modem ACCES32 This directory contains the Windows 95 98 NT driver used to provide access to the hardware registers when writing 32 bit Windows software Several samples are provided in a variety of languages to demonstrate how to use this driver The DLL provides four functions InPortB OutPortB InPort and OutPort to access the hardware This directory also contains the device driver for Windows NT ACCESNT SYS This device driver provides register level hardware access in Windows NT Two methods of using the driver are available through ACCES32 DLL recommended and through the DevicelOControl handles provided by ACCESNT SYS slightly faster Page 2 2 Manual MRDG 24 C2c SAMPLES Samples for using ACCES32 DLL are provided in this directory Using this DLL not only makes the hardware programming easier MUCH easier but also one source file can be used for both Windows 95 98 and WindowsNT One executable can run under both op
33. s added or removed In Windows 95 98 NT PCIFind EXE places itselfin the boot sequence of the OS to refresh the registry on each power up This program also provides some COM configuration when used with PCI COM ports Specifically it will configure compatible COM cards for IRQ sharing and multiple port issues WIN32IRQ This directory provides a generic interface for IRQ handling in Windows 95 98 NT Source code is provided for the driver greatly simplifying the creation of custom drivers for specific needs Samples are provided to demonstrate the use of the generic driver Note that the use of IRQs in near real time data acquisition programs requires multi threaded application programming techniques and must be considered an intermediate to advanced programming topic Delphi C Builder and Visual C samples are provided Manual MRDG 24 C2c Page 2 3 RDG 24 Manual Findbase exe DOS utility to determine an available base address for ISA bus non Plug n Play cards Run this program once before the hardware is installed in the computer to determine an available address to give the card Once the address has been determined run the setup program provided with the hardware to see instructions on setting the address switch and various option selections Poly exe A generic utility to convert a table of data into an nth order polynomial Useful for calculating linearization polynomial coefficients for thermocouples and other non linear sensors
34. t Output return values are divided into two eight bit counters The first byte of the output counters is the time remaining before the output pulse expires the second byte is the originally programmed period of free run outputs The second byte is zero for pulse outputs Examples Read digital input counter for bit 1 SEND C01 RECEIVE 0213 CR assuming 2 3hex edges since last reset of counter Read pulse output counter for bit F SEND COF RECEIVE 1F00 1F is number of timebase units remaining before pulse expires 00 indicates pulse not free run Read free run output counter for bit 17 SEND c17 RECEIVE 045F 04 is number oftimebase units remaining before pulse expires SF indicates that the duration of each period is 5F units Note It is possible to cause pulse and free run outputs to prematurely expire or change state by using the SCxxxx variant of the Set TimeBase command Also itis possible to terminate pulse and free run outputs without toggling the outputs by issuing a counter reset command rxx for each output to be terminated Manual MRDG 24 C2c Page 3 9 RDG 24 Manual Reset Counter amp Turn off Pulse or Free Run Output IXX Reset digital input counter xx XX Turn off digital output pulse or free run xx This command is normally used to reset a digital input counter to zero It can also be used to stop digital output pulses Oxx xx or free run outputs fxx xx Examples Reset digital input counter for di
35. t bit Therefore this command will always return N CR unless the T command has first been used to enable change of state detect for any given bit If a change of state has been detected since the last Y command see note the pod will return Y CR otherwise N CR will be returned Example Read COST bit SEND Y RECEIVE N CR Note The address command for any given pod will also return Y or N and clear the Change of state flag in the pod Enable Change of State Detection Tlxx Set COST mask for bits 0 7 Tmxx Set COST mask for bits 8 F Thxx Set COST mask for bits 10 17 These commands configure the bit by bit mask to enable a change of state to set the COST flag at the pod for readback by the Y or address commands If a one is set for a particular bit that bit will setthe COST flag if when the bit changes state A zero will disable change of state detection Manual MRDG 24 C2c Page 3 7 RDG 24 Manual Examples Allow bit 13 and only bit 13 to set the COST flag SEND TLOO RECEIVE CR SEND TM00 RECEIVE CR SEND TH08 RECEIVE CR Allow a change of state on ANY bit to set the COST flag Note SEND TLFF RECEIVE CR SEND TMFF RECEIVE CR SEND THFF RECEIVE CR The COST Flag is read via either the Y command or a valid address command The COST Flag is resetto FALSE by either command Select Which Edge Will Increment Counters dx Set Digital input active state on bit x dxx Set Di
36. which the equipment is exposed other than that use specified or intended as evidenced by purchase or sales representation Other than the above no other warranty expressed or implied shall apply to any and all such equipment furnished or sold by ACCES Page iv Table of Contents Chapter 1 Introduction sawakas a a Ss 1 1 Description a a E AN RRs ok a AP 1 1 Specifications neter are ee da a ai la Dan 1 3 Chapter 2 Installation 22 24 2a 5 ni ARIAS AA 2 1 CD Installation site tirs teis aa ar a Er ran ah we ete Pak 2 1 3 5 Inch Diskette Installation 22 22 con nee nenne nennen 2 1 Directories Created on the Hard Disk LLS kaka 2 2 Inst lling the BAC u AA AL E hd a Ma B A S AD ld AA 2 5 Digital Input Output Pin Connections 00 000 eee 2 7 Chapters Software me ca aes Petes aa ee ewe APAN eee ees 3 1 Command Functions A rr a ar a en Ce ee nen oR be 3 3 Error Codes o BG ate T 3 14 Appendix A Application Considerations 0 is A 1 Introduction ua a en ee a Sh we Bo ag anand A 1 Balanced Differential Signals 0 6 ee eee eee A 1 RS485 Data Transmission 0000 cc nennen ernennen een A 3 Page v List of Figures Figure 1 1 Connecting External Voltage EXV LL 1 4 Figure 1 2 Block Diagram px saga 5 442 2 Paa ha she re nee as de ee a Eher 1 6 Figure 2 1 Option Selection Map aaa aaa Aaaa aaa ias 2 6 Figure A 1 Typical RS485 Two Wire Multidrop Network Lakis A 3 List of Tab
37. with RS485 specification Up to 32 drivers and receivers allowed on line 1 O bus programmable from 00 to FF hex 0 to 255 decimal Whatever address is assigned is stored in EEPROM and used as default at next Power On e Input Common Mode Voltage 300V minimum opto isolated If opto isolators are by passed 7V to 12V e Receiver Input Sensitivity 200 mV differential input Receiver Input Impedance 12K W minimum e Transmitter Output Drive Capability 60 mA 100 mA short circuit current capability Serial Data Rates Programmable for 1200 2400 4800 9600 14400 19200 28800 and 57600 baud Crystal oscillator provided Digital Inputs e Number Up to 24 Can be programmed on a bit by bit basis on an 8 bit byte basis or on a 24 bit word basis In this latter case there would be no capability for digital outputs Sample Rate Programmable from 14 Hz to 1 KHz e Software Counters There are 16 bit software counters on all bits programmed to be inputs These can be programmed to increment on either rising or falling edges e Change of State Detection Change of state flags can be set on any enabled input bits and can be read via the serial port Logic Input Low 0 5V to 0 8V Logic Input High 2 0V to 50 0V e Low level Input Current 450 mA maximum All digital I O lines are pulled up to 5VDC via 10KQ resistors This is useful for monitoring dry contacts Manual MRDG 24 C2c Page 1 3 RDG 24 Ma
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