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General => Technical support => Topic started by: kenif on March 16, 2007, 04:16:58 PM

Title: stumped with duplicate coils
Post by: kenif on March 16, 2007, 04:16:58 PM

I am having trouble figuring out how to avoid having dupicate coils in my project.  I have done a few simple projects before with ladder logic but this has me stumped.  The application is basically a washing machine, so I need to turn the coils ( recirculation pump, valves, drain) on and off for different cycle time lengths.  Duplicating the coils looked good until I tried to compile   :( .  So here is the deal.  I have about 5 cycles of different chemicals that need to enter and exit a tank. Some need to be in for 15 minutes, some really just need seconds after the tank registers full.  Can someone point me towards and example like this? - I've been scratching my noggin for days now.

Ken

Title: Re:stumped with duplicate coils
Post by: kenif on March 16, 2007, 04:18:18 PM

I didn't mention above, I am using a T28H
Thanks
Ken

Title: Re:stumped with duplicate coils
Post by: support on March 16, 2007, 04:41:36 PM

WinTRiLOGI enforces no duplicate coil rule to avoid race conditions and hard-to find bugs caused by an output being turned ON at a certain rung and then turned OFF at another rung before the output actually get a chance to be updated to the physical memory.

You can use different internal relays (there are 128 of them in T28H-Relay) at different locations and then parallel them at the rung to drive the output coil under different conditions:

E.g  

                                  R1
|--------||---|/|----------------(OUT)

                                  R2
|---||----||---|/|----------------[Latch]

     R1                            Out1
|---||---------------------------(OUT)
|    R2    |
|---||----+
|  Seq1:2 |
|---||----+

Title: Re:stumped with duplicate coils
Post by: kenif on March 16, 2007, 04:57:54 PM

Thanks for the quick reply.  With your example, how would I increment the sequencer, and change the cycle times?

Ken

Title: Re:stumped with duplicate coils
Post by: support on March 16, 2007, 09:43:11 PM

You can use different timers for different cycle time requirement. You can also use a sequencer to select the type of cycle and the sequencer step is then use to activate the corresponding timer. When the timer times out it will turn off the internal relays that is used to control the output or it can simply reset the sequencer so that the output will turn OFF.

Title: Re:stumped with duplicate coils
Post by: kenif on March 20, 2007, 09:35:07 AM

Thank you for your help.  I have things working great now.  I managed to do it in a fairly efficient way too.