MODBUS Communications for the GF868
Contents
1. on the option bar and current setting appears here then press the appropriate Fx 8 n0 8 0dd J 8even J 7 no function key to select it See Table 1 below for a description of the options available at the above prompt Table 1 UART Bits Options Option Bar Data Bits 8 The Network ID number is used by the IDM software only Enter current setting appears here a Network ID number between 1 and 254 and then press ENT Network I D The default ID number is 1 current number appears here Note If more than one meter is connected to a network each meter must have a unique Network D 5 5 00 Setting Up MODBUS Communications cont 913 257A COMM PROGRAM Network I D current number appears here MODBUS BAUD RATE current value appears here Z Ro Ee COMM PROGRAM MODBUS BAUD RATE current value appears here MODBUS PARITY current setting appears here none l odd l even l COMM PROGRAM MODBUS PARITY current setting appears here MODBUS STOP BITS current setting appears here COMM PROGRAM MODBUS STOP BITS current setting appears here MODBUS Address current address appears here Press the appropriate Fx function key to select 2400 4800 or 9600 for the MODBUS baud rate Press the appropriate Fx function key to select NONE ODD or EVEN for the MODBUS parity setting Press the appropriate Fx function key to select 1 or 2 for the MODBUS stop bits settin2. 5 5 00 MODBUS Communications for the GF868 Installing the MODBUS Option Card Setting Up MODBUS Communications 913 257A Your Model GF868 hardware and software have been modified to provide MODBUS communications The MODBUS option card 703 1358 provides an RS485 interface with a host system while the main circuit board continues to support RS232 communications for use with a PC running Panametrics IDM software To properly set up the instrument use this addendum along with the standard GF868 flowmeter User s Manual 910 194 This document shows how to install the MODBUS option card and how to program the modified GF868 to access this special feature IMPORTANT The installation information presented here supersedes the information in the standard GF868 User s Manual The modified GF868 uses the RS485 standard for MODBUS communications This standard allows up to 32 nodes drivers and receivers on one multidrop network at distances up to 4 000 ft 1 200 m To connect the instrument s to the host system Panametrics recommends using a 24 gauge 24 AWG twisted pair cable with a characteristic impedance of 120 ohms and a 120 ohm termination at each end of the communications line The MODBUS option card must be plugged into either slot 5 or slot 6 of the GF868 On the option card pin 1 is the TMT inverting or negative connection and pin 2 is the TMT non inverting or positive connection To link the GF868 to
3. S baud rate 3MODBUS parity 4MODBUS stop bits MODBUS meter addr RESERVED Notes 1 Clear Totalizers flag from the 8051 to clear either the Channel 1 or Channel 2 totalizers 2 MODBUS baud rate 5 2400 6 4800 7 9600 3 MODBUS parity 0 none odd 2 even 4 MODBUS stop bits 1 1 stop bit 2 2 stop bits 5 AVG Error Code 0 Both Ch1 and Ch2 are in error 1 Ch1 only is in error 2 Ch2 only is in error 3 Both channels are error free 913 257A 5 5 00 Baud Rate RS232 F4 F1 00 4800 UART Bits RS232 F3 F4 F1 8even 7 0dd 7even Network I D MODBUS Baud Rate F2 F3 4800 9600 MODBUS Parity F2 F3 ODD EVEN MODBUS Siop Bits F1 Fe seed MODBUS Address NOTE Plain text represents prompt area messages and boxed text represents option bar choices Fx represent function keys to select option bar choices Figure 1 MODBUS Menu Map 913 257A 7
4. Totals Q DIGITS Q DIGITS T DIGITS 4 IEEE 32 bit 4 IEEE 32 bit 4 2 16 bit int Ch Rev Totals T DIGITS 4 2 16 bit int Ch2 Tot Digits 0 2 Ch2 Mass Flow M DIGITS 4 IEEE 32 bit Ch2 Fwd Mass Totals MT DIGITS 4 2 16 bit int Ch2 Rev Mass Totals MT DIGITS 4 2 16 bit int Ch2 Mass Tot Digits 0 2 Ch2 Timer 4 2 16 bit int Ch2 Error Code 2 Ch2 Sound Speed 4 2 16 bit int 913 257A Ch2 Molecular Weight 2 0 3 4 4 2 16 bit int 5 5 00 Table 3 MODBUS Registers for a 2 Channel GF868 cont MODBUS DPR Reg Hex Addr Description Ch2 Sig Strength Upstream Scaling decimal places Size in Bytes 4 2 16 bit int Ch2 Sig Strength Downstream 4 2 16 bit int Ch2 Temperature 4 2 16 bit int Ch2 Pressure 4 2 16 bit int Avg Velocity 2 4 2 16 bit int Avg Act Volumetric Q DIGITS 4 IEEE 32 bit Avg Std Volumetric Avg Fwd Totals Avg Rev Totals Q DIGITS T DIGITS T DIGITS 4 IEEE 32 bit 4 2 16 bit int 4 2 16 bit int Avg Tot Digits 0 2 Avg Mass Flow M DIGITS 4 IEEE 32 bit Avg Fwd Mass Totals Avg Rev Mass Totals Avg Mass Tot Digits MT DIGITS MT DIGITS 4 2 16 bit int 4 2 16 bit int 2 Avg Timer 4 2 16 bit int 5Avg Error Code Avg Sound Speed 4 2 16 bit int 2MODBU
5. g Enter a MODBUS Address number between 1 and 247 Then press ENT Press EXIT until you return to RUN mode and the screen resumes the display of data measurements Then reboot the meter to load the new settings into memory 5 5 00 i _______________________________________________ _ MODBUS Register Map To request specific parameters from the GF868 via the MODBUS the control system must enter the appropriate register number Only registers 1 through 90 are available for MODBUS communications while registers 508 through 512 are used by the GF868 to store the MODBUS parameters For details see Table 2 below for a 1 Channel meter or Table 3 on page 5 for a 2 Channel meter Note If you request Ch2 or AVE data from a 1 Channel meter the values will all be zero Table 2 MODBUS Registers for a 1 Channel GF868 MODBUS DPR Scaling Reg Hex Addr Description decimal places Size in Bytes Clear Ch1 Totalizers 2 16 bit signed Not Used 2 16 bit signed Velocity 4 2 16 bit int Act Volumetric 4 IEEE 32 bit Fwd Totals T DIGITS 4 2 16 bit int Rev Totals T DIGITS 4 2 16 bit int Tot Digits 0 2 Mass Flow M DIGITS 4 IEEE 32 bit Fwd Mass Totals MT DIGITS 4 2 16 bit int Rev Mass Totals MT DIGITS 4 2 16 bit int Mass Tot Digits 0 2 Timer 2 4 2 16 bit int Error Code 0 2 Sound Speed 3 4 2 16 bit int 4 1 1 Molecular Weight 4 2 16 bit int Signal Strength U
6. pstream 4 2 16 bit int 3A Signal Strength Downstream 4 2 16 bit int Temperature 4 2 16 bit int Pressure 4 2 16 bit int 2MODBUS baud rate 3MODBUS parity 4MODBUS stop bits MODBUS meter addr RESERVED 913 257A 4 5 5 00 MODBUS Reg 1 Table 3 MODBUS Registers for a 2 Channel GF868 DPR Hex Addr Description Clear Ch1 Totalizers Scaling decimal places Size in Bytes 2 16 bit signed Clear Ch2 Totalizers 2 16 bit signed Ch1 Velocity 4 2 16 bit int 2 3 5 7 Ch1 Act Volumetric Q DIGITS 4 IEEE 32 bit PE C Ch1 Std Volumetric Q DIGITS 4 IEEE 32 bit Ch1 Fwd Totals T DIGITS 4 2 16 bit int Ch1 Rev Totals T DIGITS 4 2 16 bit int Ch1 Tot Digits 0 2 Ch1 Mass Flow M DIGITS 4 IEEE 32 bit Ch1 Fwd Mass Totals MT DIGITS 4 2 16 bit int Ch1 Rev Mass Totals MT DIGITS 4 2 16 bit int Ch1 Mass Tot Digits 0 2 Ch1 Timer 4 2 16 bit int Ch1 Error Code 2 Ch1 Sound Speed 4 2 16 bit int Ch1 Molecular Weight 4 2 16 bit int Ch1 Sig Strength Upstream 2 0 3 4 1 1 4 2 16 bit int 3A Chl Sig Strength Downstream 4 2 16 bit int Ch1 Temperature 4 2 16 bit int Ch1 Pressure 2 3 4 2 16 bit int Ch2 Velocity 2 4 2 16 bit int Ch2 Act Volumetric Ch2 Std Volumetric Ch2 Fwd
7. the control system connect the two wires of the twisted pair cable from these terminals to the corresponding terminals at the control system Note If two MODBUS option cards are installed in the GF 868 only the card in slot 5 is activated To set up MODBUS communications enter the User Program as described in your User s Manual Then refer to the menu map in Figure 1 on page 7 and complete the following steps Note Any time the following settings are changed the GF868 must be rebooted to load the new settings into the option card Press the key and then the F3 key to select the COMM submenu On a two channel GF868 pressing the gt key and the F3 key accesses the GLOBL menu Then press F4 to select Red EXE EHHI e COMM submenu 5 5 00 Setting Up MODBUS Communications cont 913 257A IMPORTANT The serial port settings of the GF868 must match those of the MODBUS control system COMM PROGRAM This baud rate applies only to the RS232 serial port Press the until the desired RS232 baud rate appears on the option bar and press the appropriate Fx current value appears here function key to select it tn Eo EE The available RS232 baud rates are 300 600 1200 2400 4800 9600 and 19200 COMM PROGRAM The UART bits setting applies BAUD RATE only to the RS232 serial port current value appears here Press the until the desired RS232 UART bits setting UART bits appears
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