Add retries to ModbusPDU class

[mdeneen]

I tried doing this before by adding another return value, but it would break many things.

This time I have added an integer representing the number of retries to the ModbusPDU class and setting that value in both the async and sync transaction execute code path.

[janiversen]

LGTM, thanks

[mdeneen]

Hey, Jan, one downside to this is that if you enable logging it will show retries as zero with the string representation of the PDU, since the decoder action happens before the retry is set.

[janiversen]

I actually considered asking not to include it in the string representation. Feel free to submit a PR.

[mdeneen]

Other things, like device id, are also incorrect in the trace. I guess I am okay with the way it currently is.

[janiversen]

device id is correctly 0 in the response, signaling broadcast... but in general it might be better to remove all variables and just return the class name.

You seem to forget that these classes are not used exclusively in the client.

[mdeneen]

You're right, I am using them solely from the client's perspective, my apologies.

In my case, the device I am communicating with has a device id of 2. When I read holding registers I must set device_id (or slave, for older versions) to 2. The debug trace shows 0, but the actual returned object is set to 2.

Am I look at this incorrectly?

[janiversen]

In the client you know what you requested (since you can only do one request at a time) so it does not really matter what is being returned.

The main purpose of the debug log is to help the developers to find problems, it is not meant for end users.