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BACnet & PLC; question about typical BACnet object setup

BACnet & PLC; question about typical BACnet object setup

(OP)
Hey fellers,
Long time lurker, rare poster. smile

I have a piece of equipment, PLC driven, which I recently upgraded with a BACnet gateway. I'm not extremely well versed in PLC programming; I'm even more of a BACnet virgin. My current PLC and HMI has a multi-state pushbutton linked to a UINT for Hand, Off, Auto. I linked an AO object on the BACnet gateway to the same HOA tag. It works just fine. For test, I'm using YABE (Yet Another BACnet Explorer), so values that I write to an object are maintained there until I change them. 0, 1, 2 - Off, Auto, Hand. Magical. As an option, I also mapped a BO object for Hand, Off, Auto; these bits in the ladder logic are in front of one-shots. Doing that, I can get a momentary input into my existing start/stop logic, because in YABE, they're maintained at 0 or 1 until I change them. Is this necessary?

On a typical GUI for a BACnet based automation system, can the integrator make their outputs momentary? I can't do it in YABE, and I was looking over the shoulder of a guy at a job site once; he seemed to be having trouble with similar logic when controlling a VFD through a modbus gateway. Maybe this is a silly question, but like I said, I'm a BACnet virgin. I would assume that on a large system, with umpteen bazillion points, a reliable momentary output might be a challenge.

Thanks y'all,
-Mark

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