West Control Solutions ProVU 4 - Manual (Page 83)

ProVU4 Controller, Profiler & Recorder/Controller - Product Manual
Page 82 Modbus Parameters 59407, Issue 1 – March 2008
13 Modbus Parameters
The Modbus parameter addresses are detailed in the tables below.
The Access column indicates if a parameter is read only (RO) or if it can also be written to
(R/W). Communications writes will not implemented if the Writing Via Serial Comms
parameter in the Comunications Configuration menu is set to Disabled.
Note:
Some of the parameters that do not apply for a particular configuration will accept reads
and writes (e.g. attempting to scale a Linear output which has not been fitted). Read only
parameters will return an exception if an attempt is made to write values to them.
Data Formats
Data can be read or written in three formats: Integer Only, Integer with 1 Decimal Place and
Floating Point Number.
The Modbus Address column shows the register address for each parameter in integer
format. Other formats can be calculated from the Integer Only address.
When working in Hexadecimal, the format calculations are:
Address for Integer with 1 Decimal Place = Integer address plus 0x4000
Address for Floating Point = Integer address multiplied by 2, plus 0x8000
When working in Decimal, the format calculations are:
Address for Integer with 1 Decimal Place = Integer address plus 16384
Address for Floating Point = Integer address multiplied by 2, plus 32768
Example Register Address Calculations
Calculating Parameter Register Addresses
Integer Only Integer+1 Floating Point
(hex) Address Address + 0x4000 Address x 2 + 0x8000
Register Address Calculation
(dec) Address Address + 16384 Address x 2 + 32768
(hex) 0x0407 0x4407 0x880E Address Example:
(For Process Variable)
(dec) 1031 17415 34830
(hex) 0x00, 0x17 0x00, 0xEF 0x41, 0xBF, 0x33, 0x33 Data Value Returned:
If actual Value = 23.9 decimal
(dec) 23 239 23.9 as floating decimal
(hex) 0x101F 0x501F 0xA03E Address Example:
(For Selected Setpoint)
(dec) 4127 20511 41022
(hex) 0x00, 0x01 0x00, 0x0A 0x3F, 0x80, 0x00, 0x00 Data Value Returned:
If Value = 1 (Alternative SP)
(dec) 1 10 1.0 as floating decimal