YOKOGAWA PR300, User Manual

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<Toc> <Ind> < 6. Modbus/TCP Communication Protocol>
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IM 77C01E01-10E
6.4 Communication with Higher-level Devices
6.4.1 List of Function Codes
The codes in the following list are command words higher-level devices use to acquire
information from the internal registers (D registers) of the PR300.
The write function codes cannot be written into read-only or use-prohibited D registers.
Code Function
Description
03
06
08
16
Reads data from multiple D registers.
Writes data into D register.
Performs loop back test.
Writes data into multiple D registers.
Capable of reading data from a maximum of 64 successive
D registers between D0001 and D0400.
Capable of writing data to one D register between D0001 and
D0400.
Used when checking communication wiring.
Capable of writing data into a maximum of 32 successive
register between D0001 and D0400.
6.4.2 Specifying D Registers
Follow the procedures below to specify a D register from a higher-level device:
(1) If using commercially available SCADA or other software, specify the Ref No. indicated
in Chapter 7, “Functions and Usage of D Registers.”
(2) For customer-created communication programs, specify the H No. indicated in Chap-
ter 7, “Functions and Usage of D Registers.”
Example: To specify D0301 as the integration start/stop,
*Specify Ref. No. 40301 for a request using commercially available SCADA or other
software.
*Specify H No. “012C” for a request using customer-created communication program.