Hi all. I noticed that my write data and point locator test character encoding is listed as ASCII even though the data source is specified as RTU. The box is grey and I have no access to it, how do I change it to RTU?
I believe you are referring to the 'Character encoding' on the modbus data source test tools. This encoding is not referring to the transmission protocol, which could be RTU or ASCII, but instead refers to the encoding of fixed or variable length string requests. It will use the transport setting (ASCII / RTU) from the data source regardless of the setting for the character encoding on the point locator. If you select one of the String data types from the data type drop down, you will see the encoding field become editable. The ASCII in that box is opposed to being UTF8 or UTF16, not RTU.