Yokogawa Button Operated MV2000 - Manual (Page 45)

IM MV1000-17E
2-30
2.8 Reading/Writing the MV Data from Another
Device via Modbus
The MV is a Modbus server.
For Modbus specifications, see section 7.3.
Configuring the Modbus Server
You can configure the Modbus server so that another device will be able to read or write
the MV data via Modbus.
◊ Press
MENU and then select Menu tab > Basic setting mode > Menu tab >
Communication (Ethernet) > Server
• Modbus
Set the Modbus parameter under Server to Use. If you select Not (not use), you will
not be able to use the Modbus server function.
Port Number
The default value is 502. To change the value:
◊ Press
MENU and then select Menu tab > Basic setting mode > Environment tab >
Communication > Service port
For the selectable range, see section 7.1.
Reading or Writing the MV Data from Another Device
Another device (client device) sends commands to the MV to read data from the MV or
write data to the MV.
For the function codes that the MV supports and the MV registers that the client device
can access, see “Modbus Server Function” in section 7.3.
Specifying the Register Number
Specify the MV register on the client device according to the instructions below.
• If you are using a commercial SCADA system or something similar, specify the
register number (a number such as 400001; referred to as the “reference number”)
listed under Modbus Server Function in section 7.3, “Modbus Protocol Specifications.”
• If you are using a custom communication program, specify the “relative number”
in relation to the reference number. Compute the relative number in the manner
indicated in the examples below.
Examples
The relative number for input register 300100 is 99, which is the difference between
300100 and 300001.
300100 – 300001 = 99
The relative number for input register 400011 is 10, which is the difference between
400011 and 400001.
400011 – 400001 = 10