dbh6
Lifetime Supporting Member
Ok first off, i have uploaded the PLC program in a zip file, plc is a control logix. The issue i'am having is in a routine called (rtn_Pumps) i have a mode selector for a pump based on push buttons. The modes are PB_Run, PB_Standby, and PB_Off which if you see in the logic are the bits that you can use to go from one mode to another. However on Rungs 1,2,3 within that routine im using PB_Run_HMI, PB_Standby_HMI, and PB_Off_HMI, these three are coming from a momentary pushbutton from the hmi application running RSview SE that write directly to there corresponding PB_Run, PB_Standby, PB_Off tags. i also put a Always_Off branch on rung 4 in the pumps routine so i can easily for testing change between modes
Ok now that i got that out the way, i have tried numerous thing to fix this issue but, still the problem is not going away.
when i say press a pushbutton on the HMI their are times when the PLC doesn't see the pulse and never actually initiates, to further elaborate, say i'm in standby mode, if i wanted to go to Off mode i sometimes have to press the Pushbutton twice for the pulse to be seen by the plc, what i think is happening is say you press a standby push button, depending on where it is in the scan, the plc might might miss putting it into that state because of the asynchronous scan sequence of the control logix plc.
Even though it works most of the time, it still bothers me a lot that this is happening. If anyone can see the program and maybe tell me something i may have missed please let me know.
Ok now that i got that out the way, i have tried numerous thing to fix this issue but, still the problem is not going away.
when i say press a pushbutton on the HMI their are times when the PLC doesn't see the pulse and never actually initiates, to further elaborate, say i'm in standby mode, if i wanted to go to Off mode i sometimes have to press the Pushbutton twice for the pulse to be seen by the plc, what i think is happening is say you press a standby push button, depending on where it is in the scan, the plc might might miss putting it into that state because of the asynchronous scan sequence of the control logix plc.
Even though it works most of the time, it still bothers me a lot that this is happening. If anyone can see the program and maybe tell me something i may have missed please let me know.