Relays not functioning with HMI

[rjd1234]

My process uses an FX1616 BA connected to an MT6070i HMI through the 232 serial connection.  9600 baud.

I have a few internal relays that are activated using SETIO within various custom functions.  When I run the simulator in Trilogi 7, the internal relays function properly.  

In the HMI program, I also have toggle switches to allow the operator to manually activate those internal relays.

When the PLC is running the program and connected to the HMI, some of the internal relays are not being activated as they should.  

On the toggle switch settings I have a check box for "write when button is released" under the write address area.  I'm wondering if that has something to do with it.

Any thoughts?

[support]

If the HMI is writing to the same internal relay bits that the PLC is trying to control, then the PLC can only affect it once when SETIO command is run but the HMI may overwrite it immediately especially when the HMI is set to write to the relay all the time.

The better way is to for the PLC and the HMI to use different internal relays and you can then use ladder logic to connect them in parallel if either of the relay can trigger a function or in series if both relays must be ON.  You can also use a ONE-SHOT version of the contact so that if wired in parallel the circuit will only be affected by the rising edge of the relay and not every scan. It is much more flexible that way.