v2.6.11 - More fixes for Micrologix/SLC bit writes, fix issue #572

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Kyle

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Sep 4, 2025, 2:34:02 PMSep 4

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Thanks again to user @mikecflood for finding this. Writes to single bits of SLC or Micrologix were not working correctly. Unfortunately, the functions supported by the SLC/Micrologix PLCs do not allow for good RMW (read-modify-write) support. Oddly, the PLC5 series has much better support!

On a SLC/Micrologix PLC you can only write with a 16-bit mask. Due to that I have limited the support for single bit writes (via bit tags) to those tags that are 16 bits. This includes single elements from the B and N files. You can read a bit tag from nearly anything, but not write.

I would really appreciate it if those of you who have SLC or Micrologix PLCs hung off of DH+ that can be bridged from a ControlLogix could test this. I do not have such a configuration so the code for that path is untested.

This fixes issue #572.

You can find this release here.

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