plc help

[stu]

Hi guys
My mind has gone blank , im using rslogix 500 on a slc 505, I have a existing program which has a oil pump being enigized by a contactor controlled via the plc, I would like to have a timer for duration of the pump running and a timer for the intervals ( frequency ) but my mind has gone blank , can someone point me in the right direction please thanks

 

[GaryS]

Use RTO (retentive) timer for the on time and the off time
they retain the accumulated value when the rung is false then continue from thee when true
you just have to reset them at some point

 

[James Mcquade]

the control logic to turn on the pump contactor has 2 functions.
#1 - turn on the pump contactor
#2 start a motor on timer (timer 1)

when timer 1 is done, turn off the oil pump contactor
timer 1 done and oil pump off, start timer 2

timer 2 done resets timer 1

the cycle starts over.

this was done in my head, so you may need to tweek it a bit.

regards,
james.