Black Box IC820A User's Manual
Contents
1. single master in a master slave configuration where the slave devices only receive but don t transmit back In RS 422 the transmitter and receiver are always enabled to allow full duplex communications Connections require one twisted pair for Transmit another twisted pair for Receive and a ground reference wire for a total of 5 lines to operate properly To set this mode Table 1 Switch 1 RS 422 Switch 2 Echo On and Switches 3 and 4 4 wire Specifications e Signals o Transmit TD and Receive RD o RTS and CTS are looped back DTR DSR amp CD are looped back e Data Rates o Upto 115 2 kbps e Distance o Externally powered transmits up to 4000 ft 1200 m at 115 2 kbps may be less with port powering e Dimensions o 3 6x1 7x0 9 in 9 0 x 4 3 x 2 3 cm e Temperature o 0 70 C Troubleshooting Operation If an RS 485 or RS 422 device doesn t respond to data requests try swapping the polarity of the dota lines Some devices are marked opposite the RS 485 or RS 422 Standard 4 Wire devices must swap polarity of each pair Operation of the converter can be checked with HyperTerminal Set Converter to Loopback Test mode Open HyperTerminal using the COM port connected to set baud rate set Flow Control to None type characters Each character should show as typed two if local echo is on For more info visit our website Technical Library FAQ on Troubleshooting and Checking DECLARATION OF CONFORMITY Model Number 1C820A Descrip2. the receiver is enabled when not transmitting For full duplex operation the receiver is set always enabled In RS 422 mode the transmitter and receiver are always enabled The operating mode is set with 4 switches Table 1 The RS 232 signal lines power the IC820A whether they are set high or low If not enough power is available from the port or no handshaking lines are available a DC jack is provided to connect a 12VDC supply The DB9 female connector for RS 232 is wired as DCE like a modem Power No external power is required if two RS 232 output handshake lines RTS amp DTR are available and the cable run is short If the handshake lines are raised enabled and no termination is used the power efficiency is greatly increased Less than 3mA is required to operate the IC820A plus the load current For applications that do not have handshake lines or require a large load current power may be externally supplied with a 12VDC power supply with a 2 5mm plug tip positive RS 232 Operation RS 232 connections require pins 2 RD 3 TD and 5 Signal Ground Pins 7 RTS and 8 CTS are tied together and pins 6 DSR 1 DCD and 4 DTR are also tied together Any incoming data lines in either the high or low state are used to port power the IC820A The more handshake lines available the more likely the unit can be port powered Table 2 shows the RS 232 pinout Refer to matching Figures 1 to 4 for each mode for typical connections
3. IC820A 1105 pg 1 4 pn 7011 rev000 Model IC820A Universal Converter Covers All the Bases RS 232 to 4 wire RS 422 2 wire or 4 wire RS 485 Highlights Selectable RS 485 2 wire half duplex or RS 485 4 wire full duplex operation Selectable RS 422 operation Transmit amp Receive always enabled DB9 Female RS 232 Connection Terminal Blocks for RS 422 RS 485 Port power or External 12V DC power jack Automatic RS 485 Driver Control works without special programming o Enables Transmitter from RS 232 TD signal o Enables Receiver when not Transmitting half duplex Built in bridging switches for 2 wire or 4 wire modes no external jumpers e Operating Mode Switches 4 o Transmit mode Receive Mode and 2 switches for 4 Wire or 2 Wire o Receiver mode Echo On 4 wire or Echo Off 2 wire RS 485 o Two 4 wire 2 wire switches for full or half duplex bridge connections Description The IC820A Universal Converter provides RS 232 to RS 422 RS 485 conversion using either port power or an external power supply Data is converted in both directions RS 232 Transmit data is converted to balanced RS 422 or RS 485 Transmit and Received RS 422 RS 485 signals are converted to RS 232 Unlike converters which require programming hardware handshaking signals to control RS 485 or RS 422 operation the 1C820A provides automatic control In RS 485 mode the RS 485 driver is enabled by circuitry which senses the RS 232 TD input In half duplex RS 485 mode
4. See Table 1 and set Switches 1 4 to match the Operating Mode See Troubleshooting section for Loopback Test Mode Table 1 Switch Settings for Operating Mode Operating Mode half duplex full duplex RS 422 Echo On 4 Wire 4 Wire RS 485 4 Wire Mode Loopback Test Mode __ As Desired full duplex Used with HyperTerminal or another Terminal program to confirm operation of data through converter RS 422 4 Wire Mode Black Box Corporation 1000 Park Drive Lawrence PA 15055 1018 Tech Support and Ordering 724 746 5500 Fax 724 746 0746 To contact us about Black Box products or services info blackbox com IC820A 1105 pg 2 4 Figure 1 2 Wire RS485 pn 7011 rev000 Chiller PLC 2 Wire RS 485 Computer IC820A Connections _ DEY Cable TD Bey jep DATA BC A DATA A0 eet ep RD AC Process Drive RS 232 Connections DTE DCE Twisted Pair m Data B amp A Des Pin Pin DBS aon DATA AGS PRO 2 p 2 RD Internal on rip as bdi 1 Loop Back OTR 4 pett DTR fend 5_ 5_ ono DSR 6 _p 6_ DSR Cable PRIS 7 _p el 7_ RTS Internal Shield crs 8 peza crs LI Loop Back Table 2 RS 232 Pinouts Figure 2 4 Wire RS 485 IC820A Computer DB9 Cable RS 232 Connections 4Wire RS 485 Twisted Pairs Connections TD pair amp RD
5. e or two pairs for full duplex operation With a RS 485 device the transmitter driver is only active while transmitting but when not transmitting is set to a high impedance state which allows another transmitter to send data on the same wire pair In the IC820A the driver is controlled by circuitry which senses the RS 232 TD input and automatically enables transmit In half duplex operation the receiver is enabled when not transmitting Echo Off Black Box Corporation 1000 Park Drive Lawrence PA 15055 1018 Tech Support and Ordering 724 746 5500 Fax 724 746 0746 To contact us about Black Box products or services info blackbox com IC820A 1105 pg 4 4 pn 7011 rev000 The IC820A does not require any handshaking lines to control the driver in RS 422 or RS 485 mode When Switch 1 set to RS 422 the driver is always enabled When switch 1 is in the RS 485 position the RS 485 driver is automatically enabled during each Space state by the RS 232 data During the Mark or idle state the RS 485 driver is disabled and the data lines are held in the Mark state by Bias provided by the 4 7K Ohm pull up and pull down resistors The value of these resistors may need to be changed to a different value when termination is used in order to maintain the proper DC bias during the idle state RS 485 2 Wire Half Duplex This communications mode is used to connect several RS 485 devices to ihe same network with a minimum number of wires when only one
6. pair Servo Drive DTE DCE DBS Pin Pin DB ico 1 p e cp CRD 2 per RD H mst To 3 ear T Internal e 4 Peta DTR Loop Back p 4 5_ GND Pe 6 DSR TD BC EM RTS E internal Cable S aD Inspection PLC 8 CTS H Loop Back i aI p Shield RD AO Table 2 RS 232 Pinouts Black Box Corporation 1000 Park Drive Lawrence PA 15055 1018 Tech Support and Ordering 724 746 5500 Fax 724 746 0746 To contact us about Black Box products or services info blackbox com IC820A 1105 pg 3 4 Figure 3 4 Wire RS 422 Computer IC820A DBS Cable 4 Wire RS 422 Connections posi HER au Twisted pairs TD pair amp RD pair Cable Shield Set Switches to Internal RS 422 Mode Loop Back Table 1 Internal Loop Back Table 2 RS 232 Pinouts Figure 4 2 Wire RS422 No Receive 2 Wiire RS 422 Video Camera Transmit On with Focus Computer ICS20A y Pan amp Tilt Sere T N O TD A RS 232 Connections Table 2 RS 232 Pinouts RS 422 485 Operations DTE DCE Twisted Pair DBS Pint Pin DB for TD to RD cD t pati co Camera PaniTilt Internal r Loop Back or Time Displays Internal Loop Back Cable Shield pn 7011 rev000 The RS 422 standard was designed to extend RS 232 connections the RS 485 standard is an enhanced version which allows multiple drivers receivers to alternately share one pair of wires for transmit and receiv
7. tion RS 422 485 Converter Type Light industrial ITE equipment Application of Council Directive 89 336 EEC C Standards EN 55022 EN 61000 6 1 EN 61000 4 2 4 3 4 4 4 5 4 6 4 8 4 11 Black Box Corporation 1000 Park Drive Lawrence PA 15055 1018 Tech Support and Ordering 724 746 5500 Fax 724 746 0746 To contact us about Black Box products or services info blackbox com
8. unit talks at a time All units are normally in Receive mode listening for data When data is requested the addressed device waits 1 delay time then transmits afterwards goes back to receive To use this mode set Switch 1 RS 485 Switch 2 Echo Off and Switches 3 and 4 to 2 Wire Refer to Figure 1 for connections RS 486 4 Wire Full Duplex This mode is used for 4 Wire Master Slave Devices can be polled and respond faster unlike half duplex mode no turn around time delay is needed between requests and responses The RS 485 driver works the same as in haft duplex but the receiver is always enabled This can allow devices to receive information even while they are responding to a request To use RS 485 4 Wire mode set Switch 1 RS 485 Switch 2 Echo On and Switches 3 and 4 to 4 Wire When the IC820A is used as a Master in a single master system Switch 1 can be set RS 422 since it is the only transmitter When used for a Slave device the RS 232 device must provide addressability and RS 485 mode should be selected As in 2 Wire operation RS 485 Biasing is provided on Receive and should be provided on the transmit pair by the End of Line slave device RS 422 Transmit mode requires no bias on transmit Refer to Figure 2 for Connections RS 422 4 Wire Full Duplex or 2 Wire Simplex This communications mode is typically used for point to point communications over long distances with better noise immunity than RS 232 Another common use is as a
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