ProSoft Technology MVI56-AFC - Manual (Page 71)

MVI56-AFC ♦ ControlLogix Platform Modbus Database
Liquid and Gas Flow Computer User Manual
ProSoft Technology, Inc. Page 71 of 316
February 25, 2011
5.2 Primary Slave
The Primary Slave contains the main AFC database that consists of 131,072
Modbus registers. The Site and Meter configuration, as well as all live process
data and ongoing calculations are kept in the Primary Slave address space. This
address space is divided equally between the Input Register Bank (65,536
registers) and the Holding Register Bank (65,536).
The register addressing is shown in the Modbus Dictionary dialog box in AFC
Manager.
5.2.1 Modbus Address References
In these documents (the AFC Manager User’s Guide and the User’s Guide for
your platform) you will occasionally see Modbus address references like
Ph00018 or Mh00162. The first two characters of such references indicate how
to convert the following number into an absolute Modbus address in the module.
This table shows the possible values for the first identification character:
Address Translation ID Description
P Absolute Modbus address, Primary Slave
M Meter-relative Modbus address, Primary Slave
V Absolute Modbus address, Virtual Slave
This table shows the possible values for the second identification character:
Register Bank ID Description
h Holding register
i Input register
5.2.2 Modbus Address Examples
Ph02000 = holding register located at address 2000 in the primary slave
Pi02000 = input register located at address 2000 in the primary slave
Mh00100 = Meter-relative holding register located at offset 100 in the block of the
primary slave that contains the data for the meter