Bering C Sparky
Lifetime Supporting Member
I saw this tread come back around and since I have a DoMore set up on my bench, I thought I would try this out on this platform and see whats, what.
Well, I did not see an "Unlatch" instruction in the DoMore library, but there are "Set" and "RST" instructions.
The RST instruction in DoMore does not act like the OTU instruction in Allen Bradley though.
I tested it with the rungs you see below and it did not work.
I was toggling (NOT FORCING) the bits in Data View and left the C0 instruction true, to simulate a stuck HMI button....... A 0 was not moved to the C0 bit box when C3 on rung 2 became true and fired the one shot at the RST. It did not unlatch the instruction as it would have using OTU on an Allen Bradley platform.
(If you have a rig on your bench, give it a try)
So question to you guys using DoMore......How would you perform this function? (In other words, along the same lines as this thread has followed, how would you do the same in DoMore to insure a stuck HMI button unlatches, using the PLC programming to do it.)
Maybe I am just overlooking that DoMore has another instruction I am not seeing that will do this. IDK, but I do know the RST instruction does not work as OTU would in this case.
(and yes, I know the z in the one shot pictured below is backwards to represent a rising edge one shot, but use your imagination....it is correct in the program I am testing with )
BCS
Well, I did not see an "Unlatch" instruction in the DoMore library, but there are "Set" and "RST" instructions.
The RST instruction in DoMore does not act like the OTU instruction in Allen Bradley though.
I tested it with the rungs you see below and it did not work.
I was toggling (NOT FORCING) the bits in Data View and left the C0 instruction true, to simulate a stuck HMI button....... A 0 was not moved to the C0 bit box when C3 on rung 2 became true and fired the one shot at the RST. It did not unlatch the instruction as it would have using OTU on an Allen Bradley platform.
(If you have a rig on your bench, give it a try)
So question to you guys using DoMore......How would you perform this function? (In other words, along the same lines as this thread has followed, how would you do the same in DoMore to insure a stuck HMI button unlatches, using the PLC programming to do it.)
Maybe I am just overlooking that DoMore has another instruction I am not seeing that will do this. IDK, but I do know the RST instruction does not work as OTU would in this case.
(and yes, I know the z in the one shot pictured below is backwards to represent a rising edge one shot, but use your imagination....it is correct in the program I am testing with )
BCS