Yokogawa Touch Screen GP20 - Manual (Page 333)

4-13
IM 04L51B01-01EN
Using Modbus Functions (Communicating with Modbus devices)
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App
4.5.2 Modbus Server/Slave Function
Function
The GX/GP supports the following functions.
Function Code Function Operation
1 Read the coil status
(0xxxx)
The client (master) device reads the coil status of the GX/
GP.
2 Read the input relay
status (1xxxx, 1xxxxx)
The client (master) device reads the input relay status of
the GX/GP.
3 Read the hold register
(4XXXX, 4XXXXX)
The client (master) device reads the GX/GP data.
4 Read the input register
(3XXXX, 3XXXXX)
The client (master) device reads the I/O, math, alarm,
time data from the GX/GP.
5 Change the single coil
status
(0xxxx)
The client (master) device changes the single coil status
(off/on) of the GX/GP.
6 Write to a single hold
register (4xxxx, 4xxxxx)
The client (master) device writes to a single hold register
of the GX/GP.
8 1 Loop-back test The master device performs a GX/GP loopback test.
15 Change the coil status
(0xxxx)
The client (master) device changes the coil status (off/on)
of the GX/GP.
16 Write to the hold register
(4XXXX, 4XXXXX)
The client (master) device writes to the GX/GP
communication channels.
1 Loopback test is only for serial communication.
4.5.3 Register Assignments (Shared with the Modbus server/slave function)
Input Register
Type GX/GP Register
Number Data Type
I/O channel I/O data 300001 to 301000 32-bit signed integer
301001 to 302000 32-bit floating point
302001 to 302500 16-bit signed integer
Status information 302501 to 303000 16-bit signed integer
I/O channel
(continuous area)
I/O data 304001 to 304200 32-bit signed integer
304201 to 304400 32-bit floating point
304401 to 304500 16-bit signed integer
Status information 304501 to 304600 16-bit signed integer
Math channel Math data 305001 to 305200 32-bit signed integer
305201 to 305400 32-bit floating point
305401 to 305500 16-bit signed integer
Status information 305501 to 305600 16-bit signed integer
GX/GP status 308001 to 308007 16-bit signed integer
Client/Master device
Read
4.5 Modbus Function and Register Assignments