IamJon

I apologize for the confusion. I was heading out of the office when I posted it, so I was in a hurry, but didn't want to scan and post the entire thing.

Yes, the pump dead heads for a second or two. We ended up changing the TDR to a delay on operate, and put contacts for the motor running and a new relay in front of it. See attached. Schematic-1.pdf

We have two. I just didn't put the start logic in what I posted here.

^ That won't work. I didn't show enough on the start. The pump will start, there's a time delay, then the valve opens. If I put the NC for the Valve Open coil, the motor won't latch until the valve starts opening. That would mean the operator would have to hold the Start button until the time delay was exceeded.

In my company's standard spec, we call for a type RK5 for 0-30A fuses. Type RK5 are rated 0-600A, type CC are rated 0-30A The contractor submitted type CC time delay. Is there a reason to spec type RK5 for a 0-30A application? Should I accept CC? Should I change the standard spec to use CC for 0-30A?

That ended up being what the CC fuses were for this time, and I accepted them.

A year later I run into the same thing, someone submitting CC fuses. I know I've been over it before, google it, and come back to my original thread Guess I have more CC fuses to reject.

I've heard it's safe to cross control wiring and AC power at 90 deg. Can someone verify that this is true? What about the voltage rating on the cable? Should I make it all shielded, including the 120VAC digital signals? ETA: We're trying to keep it out of conduit, so we're running in trenches, and the cables need to cross somewhere.

There is a well with a level transmitter. The LT is calibrated for 0-35' but the real level is 2-37' The raw value in the PLC is 210-1023 (due to 4-20 to 2-10V conversion with 500ohm resistor). So raw 210-1023 = 2'-37'. What is the raw value at 10'? I solved this the other day and was confident in my solution. Well, today I went to verify my values, and I couldn't get the same value I had before (just one of those days ) . My previous value today looked like 12' instead of 10'. Anyway, I got 442 for 10'. PS: for clarification, 0 raw does not equal 0'. 0-210 raw is 2'. 210 is the minimum value.

Rockwell Software?

The chart on the Effects of Increasing a Parameter Independently has always helped me tune PIDs. http://en.wikipedia.org/wiki/PID_controller That's most of what you need to know for PID control when it comes to PLCs.

Oh, man. That's what I kept getting yesterday. I was thinking yesterday that it was wrong to add in the 210 at the end. Ok here's what I did. get values scaled at 0 min: 1023-210 = 813 raw; 37-2 = 35 eng get a 1' raw value: 813/35 = 35/35; 23 = 1' Solve for 10': 23*10 = 230 add in 210 to bring it up to normal scale: 230+210 = 440. But I should not have done this, because our value of 210 was 2' already. The actual mistake was solving for 10' instead of 8'.

Use a smaller time base, like .01, and use 500 as your preset. It will be a more accurate timer this way. Try putting a NC T4:1/DN in front of T4:1.

I know, I feel like I'm spamming this site this week... I'm setting up a program for Proportional control using the PID instruction. - Level Rising At a raw value of 442 I want the Lead to come on at 75%. It will rise with the level until it is 100% speed at 479. The Lag will come on at 489 and run at 100%. 3rd pump comes on at 535 across the line start. - Level Falling 3rd pump stops at 510. Lag stops at 479. Lead starts coming down from 100% at 479, hits 75% at 442. Lead shuts off at 229. I have my file attached. The PID is under PUMP CNTRL file. My level setpoints are under LVL CNTRL. I would like my PID settings to be checked to verify if they are correct, and to verify that my latching and unlatching for the level control won't be fighting each other. It looks good to me but I'd like a second pair of eyes. Thank you! ROAD_PS_PID.RSS

Thanks for the help. The project is up and running

I can't get on RS500 right now, but I can explain what I did. You're doing a lead/lag routine. Some use latching, I used a counter. Use your levels to activate lead and lag pumps through latching bits, then unlatch at the level you want your pumps to turn off at. So if level GRT 8000, latch lead. Level GRT 12000 turn on lag latch. Level LES 12000 or whatever, unlatch lag, level LES 3000 unlatch lead. Use the counter to determine which pump is lead and which is lag. Use a ONS to count up every time the lead pump turns off, and reset your counter when the ACC value = 2 (0=P1 lead, 1=P2 lead). You'll have your pump start rungs which should be pretty simple with two pumps. A few things that would help (again I can't see your program). Are you using VFD's? If so, describe your speed control, ie, speed setpoints at certain levels. The field thing will be separate from which pump is running, so don't try to relate the two by which pump is running should determine which field. You can use a counter for this also, same way as for lead/lag. Throw some logic in so that if P1 is lead, and lead is called for, but P1 is off/not in auto/out of service etc, MOV a 1 into the lead lag counter so P2 will be lead, then vice versa. The way to keep it simple is to view the lead/lag separate from the pump control logic, separate from the field logic, then combine them. Putting them in different files will help you organize this. Don't forget your JSR's to scan all your subroutines (files).

Just a skim through and I have this question along the same lines... Do we know if it's an IO card fault or a SLOT fault? Was a different IO card used in the same slot, or the faulted card used in another slot, maybe in another chassis? And yeah, firmware reload... I'd replace the PLC as Paul suggested. What made you think you needed a firmware reload? I've had a PLC go stupid on me once, couldn't d/l to it. I started a fresh, blank program with only the correct PLC (SLC) put into it, and downloaded that, then I was able to re-download my program and get it running.

I posted a few threads in the AB section. I just want to thank everyone who helped me get my bearings back with controls. The project is wrapped up and everything is running well. Thank you!

Everyone keeps telling me I can send multiple words in a MLx1100 message, but I keep getting ERROR 10, unsupported command. Does it sound like I need to increase my timeout? I have one set at 33 but it only seems to try for about 1 second before it errors. I'm messaging over Viper Ethernet Dataradios.

Thanks for the reply! But I got it covered. I have no idea why it was error-ing. I went back to my repeater plc and redownloaded the same program as was already there, and the system started working. I just had a thought... we should put together a MSG tacked thread with examples of messages between Mlx-mlx, mlx-clx, etc, with a CIP generic also. Here's a thread of mine with lots of info that might help start it off: http://forums.mrplc.com/index.php?showtopi...&hl=message I think it would be best if one of the mods started it and could tack it and update the original post as examples flow in.

Oh... for #3, that is just test logic. I was making sure my lead/lag was cycling. Thanks for the SCP function info, I've never used that instruction and it helped simplify my program. The literature for the 1762-IF2OF2 states the scaled output values at 3120 for 4mA, 15600 for 20mA, and 16380 for 21mA. I assume for my 75-100% output, I should use 75-100% of the 3120-15600 range? I'll do that unless I hear otherwise.

I'm copying this from a post I made in another thread so I don't hijack that one. This is what I have so far in my message : Channel 1 on the 1100 is Ethernet. Comm command I think should be CIP Generic. Data Table Address - put the first WORD of your data, not bit (as read in instruction help) Mine is N7:1 Size - 1 for one 16 bit byte. Extended Routing Info file - create a new data file for this. Must be a new thing? The help doesn't say anything about the service, and the multi hop seems to only be peer to peer with Clx devices? I have errors on my messages, so I can't even DL it into the processor to try by trial and error. Anyone have an example of how to set up this type of message? Thanks.

I called their tech support and they agreed with your statement. I installed the programs but didn't have time to get everything up and running. By the time I realized some things I had wrong, I had to run across town to change it, and we have 3 plc's to change. I should have it running Monday morning. Then on to the PS control.

Thanks for the input! So far the only thing I've been able to test is the lead pump. It turned on and shut off when it was supposed to, but I didn't even get a chance to look at the speeds.

Then do a compare on what they enter. If it is greater than 1000, then do a move instruction and move 1000 into the register. Less than 500, move 500 into the register. Actually, you might be able to do this with a LMT, or limit instruction...