thedeester1
Member
Firstly Ive not been using this page for long and this is my first post. Hello all and thankyou for the answers ive found here upto yet.
My question regards timer accuracy in allen bradley PLC's. Ive written a program to test a valve array. the program times the time each valve takes to open, how long its open and then how long it takes to close. Firstly the program it written on an SLC 5/03. I dont think it will be fast enough to time the events since it doesnt seem to accept a time base of less than 0.01s. Is this down to rs logix or the CPU limitations? Secondly if its the CPU do the compact logix CPU's have a 0.001s time base?
Ive used the SLC mainly to develop the program since theres boatloads lying around where i work. To use a different CPU would mean spending money and i need to know its right before i shell out on a new system. Ive tried reading the selection guides but they rarely quote timer bases.
Appart from this im worried that scan times may affect accuracy?
The program isnt that long (300ish rungs) but does include a large number of timers moving values into interger's which are then compared to alarm values testing for slow or non operation of the valves. Any input to this would be helpfull since i dont wanna waste any more time or money if its an impossible cause?
My question regards timer accuracy in allen bradley PLC's. Ive written a program to test a valve array. the program times the time each valve takes to open, how long its open and then how long it takes to close. Firstly the program it written on an SLC 5/03. I dont think it will be fast enough to time the events since it doesnt seem to accept a time base of less than 0.01s. Is this down to rs logix or the CPU limitations? Secondly if its the CPU do the compact logix CPU's have a 0.001s time base?
Ive used the SLC mainly to develop the program since theres boatloads lying around where i work. To use a different CPU would mean spending money and i need to know its right before i shell out on a new system. Ive tried reading the selection guides but they rarely quote timer bases.
Appart from this im worried that scan times may affect accuracy?
The program isnt that long (300ish rungs) but does include a large number of timers moving values into interger's which are then compared to alarm values testing for slow or non operation of the valves. Any input to this would be helpfull since i dont wanna waste any more time or money if its an impossible cause?