TheWaterboy
Lifetime Supporting Member + Moderator
I've asked this before but I still couldn't make it work. I just can't envision a solution.
Local RTU has a screen to set a handful of setpoints. Historically all adjustments have been made locally using the OI. The Main Plant now wants to control these same setpoints as well over telemetry.
How can that be done? If the Telemetry package contains old setpoints, which it will, it will always overwrite the local ones each poll. In addition the Main Plant would never know the setpoint was changed unless I read it back.
I can envision a complicated readback method that will require multiple reads and writes to each location. I can also imagine sending one set of setpoints to one array location and local ones elsewhere and using a selector at the local to set which setpoint to use. But I don't like the complication of those options.
I'm hoping I just haven't thought of a simple technique for this. I can't be the only one.
Local RTU has a screen to set a handful of setpoints. Historically all adjustments have been made locally using the OI. The Main Plant now wants to control these same setpoints as well over telemetry.
How can that be done? If the Telemetry package contains old setpoints, which it will, it will always overwrite the local ones each poll. In addition the Main Plant would never know the setpoint was changed unless I read it back.
I can envision a complicated readback method that will require multiple reads and writes to each location. I can also imagine sending one set of setpoints to one array location and local ones elsewhere and using a selector at the local to set which setpoint to use. But I don't like the complication of those options.
I'm hoping I just haven't thought of a simple technique for this. I can't be the only one.