APPLICATION EXAMPLE

Modbus user map setup

DESCRIPTION GE Multilin Relays and Meters support the Modbus User Map feature in their software. This feature can be used with the P485 to reduce the number of Modbus transactions and improve communication speed.

PQMII USER MAP There are six parameters to be read from PQMII as indicated in the previous section. Normally, six read input register command transactions are required to read these parameters. However, these parameters can be grouped together with the Modbus User Map feature and read using only one read input register command transaction.

Set the Modbus User Map for the PQMII as follows.

1.Start the Enervista PQMII Setup software.

2.Establish communication between the device and PC.

3.Select the Setpoint > User Map menu item.

4.Set the user map registers as follows and save to the meter.

User map address

Parameter

User map data

 

 

address

 

 

 

 

 

 

0000

0x0240

0x0100

 

 

 

0001

0x0241

0x0101

 

 

 

0002

0x0242

0x0102

 

 

 

0003

0x0244

0x0103

 

 

 

0004

0x0245

0x0104

 

 

 

0005

0x0286

0x0105

 

 

 

Figure 9-1: PQMII meter user map setting

The six parameters are now mapped to user memory map data at 0x0100 to 0x0106. These parameters can now be read by one Read input data register command at 0x0100 with register length = 7 words (note that average phase voltage value is in 32-bit).

MM2 USER MAP As indicated earlier, there are five parameters to be read from MM2. Normally, five read input register command transactions are required to read these five parameters. However, all the parameters can be grouped together using the Modbus User Map feature and read using only one read input register command transaction.

Set the Modbus User Map for the MM2 as follows.

1.Start the MM2PC software.

2.Establish communications between the device and PC.

3.Select the Setpoint > User Map menu item.

P485 MODBUS TO PROFIBUS CONVERTER – USER GUIDE

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GE P485 instruction manual Modbus user map setup, Parameter User map data Address