I am not a novice programmer but I have never used the N7 registers the same way I would use a B3. However I am modifying a program for a customer and the original author used the N7 registers.
I have read several posts and as I understand it the N7 registers behave exactly the same as a B3 when addressed througn XIC, XIO, OTE. If that is all correct then when a bit is latched in an AB Micrologix 1500 it HAS to be unlatched later in the program. This is true for B3 and N7 correct?
So if you saw:
B3:0/0(L)
B3:0/1(L)
And there were no (U) instructions for either of these anywhere in the program once they went true they would stay on forever correct? (even through power loss)
So if they are then used like this:
B3:0/0XIO B3:0/1XIC
They would cancel each other out and the rung would never go true correct?
Either I am losing my mind or this program should never have worked. There are 15 latched bits that are never unlatched anywhere in this program. Does anyone have any thoughts here?
Thanks a million,
Don
I have read several posts and as I understand it the N7 registers behave exactly the same as a B3 when addressed througn XIC, XIO, OTE. If that is all correct then when a bit is latched in an AB Micrologix 1500 it HAS to be unlatched later in the program. This is true for B3 and N7 correct?
So if you saw:
B3:0/0(L)
B3:0/1(L)
And there were no (U) instructions for either of these anywhere in the program once they went true they would stay on forever correct? (even through power loss)
So if they are then used like this:
B3:0/0XIO B3:0/1XIC
They would cancel each other out and the rung would never go true correct?
Either I am losing my mind or this program should never have worked. There are 15 latched bits that are never unlatched anywhere in this program. Does anyone have any thoughts here?
Thanks a million,
Don