Valmet Damatic MODBUS RTU communication protocol
Supported device types and versions
MODBUS protocol, version RTU, supports data reading from a control system Valmet Damatic by means of gateway RTU GTW:LIS.
Communication line configuration
- Communication line category: Serial.
- Parameters of asynchronous line depending on the design and type of device connection – literature "Overview of the Damatic XD System – VALMET Automation V.5.4 rev.7".
Communication station configuration
- Communication protocol: Valmet MODBUS RTU GTW:LIS.
- Station address is a decimal number in the range of 0 to 255.
Station protocol parameters
There can be defined the following parameters:
|Key word||Full name||Meaning||Unit||Default value|
|RC||Retry Count||Number of retry calls when an error in communication occurs.||-||2|
|RT||Retry Timeout||Delay between retry calls if an error in communication occurs.||ms||300 millisec.|
|WFT||Wait First Timeout||First waiting on the response after sending a call.||ms||200 millisec.|
|WT||Wait Timeout||Delay between the readings of a response until it is completed.||ms||100 millisec.|
|MWR||Max Wait Retry||Number of retry response reading until it is completed.||-||10|
String with protocol parameters is written according to this rule:
If a key word with valid value has not been found in the initial string, default value is used according to Table 1.
I/O tag configuration
I/O tags: Ai, Di
Address – a decimal number in the range of 0 to 65535 – number of MODBUS register.
In general, 2 bytes are read (sign integer) from a particular register. For Ai points, IEE 754 standard can be used, which is a reading of 4 bytes in FLOAT, i.e. the registers on Address and Address+1.
For Di points, number of bit must be from the range of 0 to 15 – one bit from 16 bits from MODBUS register which was read.
Changes and modifications
- Ver. 1.0 – February 9, 2000