time and comms delay

[roxusa]

I have an SLC 503 running a machine with a scanner and 1794 RIO. One of the functions is a register motor on a printing cylinder. The manual 3 position spring return to center selector switch for Advance/ Retard which is wired to RIO inputs will increment the cylinder 1/8-1/4" with a quick flip of the switch.
I also have Advance/Retard on a Panel view that is ethernet through an Ethernet to RS232 converter to the SLC.
My question even with the lowest possible touch response setting on the Panel view a quick tap on the screen moves the Cylinder 3/8-5/8" The motor is
controlled with a standard reversing contactor. I understand there could be delay in comm's with the Ethernet /RS232 converter but cant understand why I would be getting the longer pulse. Can this still be associated with comm's
somehow?

 

[Steve Bailey]

why I would be getting the longer pulse. Can this still be associated with comm's

When you touch (or click) an object on the HMI, it writes a 1 to the associated bit in the PLC. When you take your finger off the object it writes a zero. The time between writing the 1 and writing the zero can be a lot longer than the time between touch and release.

 

[Ken Roach]

My guess is that the PanelView is using a "Momentary Pushbutton" object.

That is one of the things PanelView Plus has never done particularly well.

They work like Steve said: when you press, the PanelView writes a "1" and when you release it writes a "0". The time between the PanelView attempting to perform that function is either the actual hold time, or the "duration" setting for the Momentary Pushbutton object (whichever is greater).

But the performance of those objects isn't great. The PanelView is also reading all the devices on screen, and any trend objects, and background data. And on your system, all of that has to be processed by the Ethernet/RS232 converter, and then by the CompactLogix.

You might consider using a set of buttons arrayed for Advance / Retard with a specific increment each, instead of relying on quick button presses on the HMI.

 

[Rob...]

One method I've used with these panels is, use the panelview button to set a bit. In the PLC reset that bit and have a separate internal bool/whatever to perform logic.