Experimental Physics and
Industrial Control System

Some additional info regarding this problem of writing to soft tags.

First, I should have made clear this has to do with bo records.

Second, if I compare a hardware tag and a soft tag I see that when they are read the hardware tag, e.g. Local:9:O.Data[0], is treated as a bit in an integer whereas the soft tag reads back as a boolean, value =255 or 0.

For EIP_verbosity=10 the following excerpt illustrates this, there is a record that references Local:9:O.Data[0] which results in the tag Local:9:O.Data being read back as a group of bits and a record that references the soft tag remote_reset_a and reads back the boolean value 255 ("on").

It seems to me that when I subsequently try to write a zero to the soft tag remote_reset_a, the value 255 is treated by the Ethernet/ IP driver as a collection of bits, the lowest bit is set to zero to generate the value 254. This is then written and interpreted by the controller as "on". (?)

Yes, the network protocol used by the Ethernet/IP driver
doesn't really know 'boolean' nor 'bit'.
The driver reads/writes integer data,
and depending on the record type it assumes
that you really meant to deal with only a bit
in the integer, except when you use the 'B' flag etc.

So in order to look at this, I
really need the exact record definition.
Preferably: The definition of the one and only record
in your database that reproduces the problem.
Also the RSLogix declaration for your "soft tag".

References:

Ethernet/IP: writing zero to soft tags --- More Info John Dobbins

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