RSLogix 500 for valve sequencing

Hi all

I'd like some upto date help of "modern" programming techniques in carrying out valve sequencing of 5 water filters. One filter looks like below with 6 valves operated by SOV's with open/ close limits for valve position. I'm not a PLC programmer, more a fault finder so at the moment I'm thinking "old & basic" by using valve limits to operate "Relays" and "Timers" rung by rung.

Can anyone offer any advice of using other functions within the RSlogix500 to carry out the sequence?

Vent <---V7--- ----V1-----< H2O In
| |
| |---V5----->Back Wash H2O Out
|-----------|
| |
| |
| filter |
| |
| |
|___________|
| |
>X---V6-----> |-------V2----->H2O Out
Blower Air In |
|_______V8____>Drain


The sequence is as follows, where 1=open/ run & 0=closed/ stop;

Blower V1 V2 V5 V4 V6 V7 V8
Online 0 1 1 0 0 0 0 0
Offline 0 0 0 0 0 0 1 1
Drain 0 0 0 1 1 1 1 0 for 2 minutes
Air Scour 1 0 0 0 0 1 1 0 for 5 minutes
BW Air/H2O 1 0 0 1 1 1 1 0 for 10 minutes
BW H2O 0 0 0 1 1 0 0 0 for 10 minutes
Refill 0 1 0 0 0 0 1 0 for 1 minute
Rinse 0 1 0 0 0 0 0 1 for 5 minute

Any pointers greatly appreciated, Thanks in advance
Graham

Whoops, try the notepad attachment instead. ThanxNT

Thanks

You may want to take time to learn the RSLogix500 Instruction Set, there are sequencer commands available. Look at the SQO instruction and do a search on this site for sequencers, there have been many examples posted.

Use a counter to define your stages. Each stage is defined by a timer. When each timer expires, it's done bit advances the counter. The output coil controling each valve or blower will be preceeded by an array of logic defining which counter stages will call the coil. When the timer of the last stage has expired, reset the counter to zero. A counter value of zero will be used to call whatever valves are to be open during the On Line stage. To start a backwash, use some logic to advance the counter from 0 to 1. 1 is the first stage. Use logic to set a bit if the counter value is greater than 0. Use this bit to light a pilot light or display a message on an OIT.

Thanks RSDoran & Godfrey

Thanks lads

I'll give your ideas a try out. Be back on the forum in due course.

Albatross