Panasonic GT series, Manual

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10-4
10.3 Modbus (RTU Mode) for Temperature Control Unit,
etc
PLC model selection
Device setting: Start No. *****0
Select "Modbus (RTU mode | Temperature control unit, etc)
Overview of communication
Only function codes "03" and "06" which are the command to read/write the contents of the holding
registers are used. The function code "03" is a message to enable the contents of multiple holding
registers to be read, however, GT reads the number of holding registers by 1 word.
For outputting bit, read the value of the holding register to be output and change the bit before writing.
Usable devices
Bit/Word Device No.
Bit Device Holding register 400000.0-465535.F
Word Device Holding Register 400000-465535
Communication Parameters Settings
The example of communication settings of GT and a device such as temperature control unit is shown
below.
Setting Values for GT (Set in the configuration setting of GTWIN.)
Item Setting
PLC Unit No. 1
Baud Rate 19200bps
Length of Bits 8
Stop Bits 1
Parity Even
Setting Values for Temperature control unit, etc
Item Setting
Station Address 1
Mode RTU
Baud Rate 19200bps
Length of Bits 8
Stop Bits 1
Parity Even
Precautions when making communication settings
When connecting the GT via RS485, set the transmission delay in GT Configuration to 5 ms or more.
(The appropriate values vary according to equipment to be connected. Check with actual equipment.)