Configuring the MES1A/B
0B (hex) - Target Device Failed to Respond
•If the slave did not answer, or the answer contained a CRC error
•If a TCP socket is open, but no response is received within the defined message timeout period
•If a TCP socket is open, but the remote Modbus TCP slave/server returned exception 0B (hex)
Disable Modbus/TCP Pipeline
Typically a Modbus master issues a query and waits for a response before issuing another. However, when using Modbus/TCP, multiple queries can be issued and the MES1A/B will buffer them in a “pipeline”. The MES1A/B can fetch each query one at a time, and respond. In some situations this is useful, but in others the sequence of query/response can get out of sync (especially if any queries or responses are lost). The Disable Modbus/TCP Pipeline setting allows you to decide how you want the system to operate.
•Setting this field to 1 = No configures the MES1A/B to allow pipeline operation. This is considered the safest default setting. It is recommended that you choose this option unless you are experiencing problems.
•Setting this field to 2 = Yes configures the MES1A/B to always fetch the latest request from the TCP buffer (discarding all older requests).
Character Timeout
Although Modbus/RTU specifies a 3.5 character time out period between characters, the Character Timeout field allows you to set a custom value for this field.
•If you set this field to 0, the MES1A/B will automatically calculate a minimum timeout based on the baud rate being used.
•Although you can set this field to any value between 1 milliseconds and 6959 milliseconds, a recommended safe value for general use is about 50 milliseconds (which is the default value).
Message Timeout
The Message Timeout field allows you to set the timeout period for responses from a connected slave to any value between 200 milliseconds and 65000 milliseconds. The default value is 5000 milliseconds.
Manual Documentation Number: |
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