Need Help Getting Plant Running

[sparkytex]

Hey guys,

I'm at a waste water treatment plant trying to get their UV system running. I've traced the problem down to a AOI that's causing the failure in sequence. I Attached a few pictures of the AOI in the logic as well as the definitions, properties, and the AOI logic itself.

You will see in Rung 5 PHPPWWTP_UVGeneral.Seq_Start[1].ready is true and I've also seen that PHPPWWTP_UVGeneral.Seq_Start[1].Req_Start was also true which is the signal from another PLC telling the UV system to start. It isn't true in the screen shot because I've had to bypass the UV system which cancels that signal from the Treatment PLC.

I'm not super familiar with AOI's but know a bit about them. I can't seem to find what AOI "PHPPWWTP_UVGeneral.Seq_Start[1]" is missing which isn't allowing it to complete it's sequence. I tried to attach the PLC Program but it is too large, even in a compressed folder so I took a bunch of screen shots.

PHPPWWTP_UVGeneral.Seq_Start[1} AOI is what starts the UV system start sequence. There are 7 AOI sequence steps starting with #1 and its not finishing it's sequence. I know this because it has the visible Discrete outputs on the right side of the AOI saying showing the status "Done Start". It also Isn't showing it's "Command" output bit on the right side of the AOI either.

Can some one point me in the right direction as to where I can find out what's stopping this AOI from executing?

thanks,

Tex

 

[Gomez_]

What is that reset bit doing when the UV isn't bypassed?

 

[sparkytex]

Also, Here is an attached picture of the AOI with bit "PHPPWWTP_UVGeneral.Seq_Start[1].Req_Start" bit being true just so you can seem what AOI PHPPWWTP_UVGeneral.Seq_Start[1] looks like with PHPPWWTP_UVGeneral.Seq_Start[1].Req_Start true.

 

[sparkytex]

What is that reset bit doing when the UV isn't bypassed?

This is where my unfamiliarity with the AOI's comes into play. where do I find the Reset bit for the Specific AOI. I know I can see it in the ADD ON Instruction logic but that just pertains to the general "Addon_Seq_Step" AOI that hes used trough out this program.

Is there a way to see AOI PHPPWWTP_UVGeneral.Seq_Start[1]'s specific logic?

 

[Gomez_]

It looks to me like the reset bit is being held on by something outside the AOI.

Look for "PHPPWWTP_UVGeneral.Seq_Start[1].Reset" and see what logic touches that.

 

[sparkytex]

What is that reset bit doing when the UV isn't bypassed?

It looks to me like the reset bit is being held on by something outside the AOI.

Look for "PHPPWWTP_UVGeneral.Seq_Start[1].Reset" and see what logic touches that.

Ok I found the PHPPWWTP_UVGeneral.Seq_Start[1].Reset Bit and it seems like a random manual shutdown bit was holding the PHPPWWTP_UVGeneral.Seq_Start[1].Reset bit true which wasn't allowing the AOI to execute.

The UV system has now started and Is online. How did you know to look for the reset bit? Was is because the PHPPWWTP_UVGeneral.Seq_Start[1].Req_Start and PHPPWWTP_UVGeneral.Seq_Start[1].Ready were both true and it wasn't executing and the only thing that could stop that from happening was the PHPPWWTP_UVGeneral.Seq_Start[1].Reset bit?

Thanks for your help it is greatly appreciated.

Regards,

Brian

 

[Gomez_]

When I looked at screenshot 3 and 4, it looked like reset was the only thing that could really kill the AOI like you described, and I noticed it was on from screenshot 1.

 

[sparkytex]

When I looked at screenshot 3 and 4, it looked like reset was the only thing that could really kill the AOI like you described, and I noticed it was on from screenshot 1.

I didn't even notice that Reset bit showing as a "1" on the front of the AOI instruction. Noted for the future to look at the faceplate of the instruction for the reset bit being true. What happened is a level transmitter went crazy telling the plant to start and stop constantly and everything got out of sequence.

thanks again for your help bud,

brian

 

[Gomez_]

No problem man, gave me an excuse to procrastinate on my own work