DCP200 Profile Controller & Recorder - Product Manual
51-52-25-150, Issue 1 – April 2009 Modbus Parameters Page 83
13 Modbus Parameters
The Modbus parameter register 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 be implemented if the Writing Via Serial Comms
parameter in the Communications Configuration menu is set to Disabled.
Note:
Some 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
Register Address Calculation
(For Process Variable)
If actual Value = 23.9 decimal
23.9 as floating decimal
(For Selected Setpoint)
If Value = 1 (Alternative SP)
0x3F, 0x80, 0x00, 0x00
