XL15C programming

[gman994]

Anyone know of any resources for browsing programming examples. I can read all of the help screens, and H-Well literature that was ever printed, but it all has little relevance to me unless I can see it applied. The control loop configuration is somewhat of a puzzle to me, primarily the sequencers, and the resulting EPIDS. I realize that this control is very flexible and can do a lot of things, but I sometimes wonder that if that is what's desired, then why not use a control that utilizes line programming or ladder type logic that is consistent throughout its setup as opposed to a control like this that appears simple, but has a regimen of adherence that has to be learned for each facet of programming. Maybe when I get more experience with it, this will seem like a stupid question, but until then, I'll have to just "think" I'm an idiot, until someone confirms it. ---gman

[codewriter]

I think you are probably getting confused because you are over thinking it. I also think they failed when they called:
Seq1 = Heat
Seq2 = Econ
Seq3 = Cool

I have never setup a control loop to work all three of those values, and can not honestly say that I feel that would be the best way either.


I have however use the sequencer for tasks like this:

SEQUENCER:
Seq1 Start: X%=0 / Y%=0
Seq1 End: X%=33 / Y%=100
Seq1 Start: X%=33 / Y%=0
Seq1 End: X%=66 / Y%=100
Seq1 Start: X%=66 / Y%=0
Seq1 End: X%=100 / Y%=100

OUTPUTS:
Seq1 Output = AO1 (cooling valve #1)
Seq2 Output = AO2 (cooling valve #2)
Seq3 Output = AO3 (cooling valve #3)

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Or even if you have say multiple cooling towers, and you want to ramp them indivedually based on the same sensor value. You could do similiar to above, and ramp VFD1-VFD2-VFD3, etc...

--------------------------

The Seq output does not have to be a hardware point, it can be a pseudo point and be able to be fined tuned elsewhere. For example you could use the pseudo point in a logic loop and setup limits, safties, etc... then use the logic loops output as the hardware connection point for the controlled device.

--------------------------

Am I confusing???

[lwarren]

I feel you pain gman, the LCBS system was created for the light commercial contractor. I have always found configuring the 15C a challenge, but I don't use it much either. I'll stick with Care anyday.

[codewriter]

I setup sheets in excel to help me keep track of what I was programming in the 15C, it helps alot. I basically write what I want to happen in line code but I put the "LL/CL/etc..." next to the line that it resides in. Its an extra step, but once you get used to it, it is pretty fast. Plus when you need to add to the system later, or trouble shooting, its much easier to look at the excel file than try to figure out what the heck is going on by clicking tabs back and forth on LonSpec.

The good thing is, I would look for a drastic change in LonSpec within the next two years. I have a weird feeling they are going to add some features to it that will make it easy for both the rookie and the seasoned. LonSpec is extremly easy for basic straight forward system, but throw anything in there that requires mulitple LL's or CL's to accomplish a single task, and it can be hell for a unorganized rookie.

[theirb]

The 15C is less of a challange to program than th 15A. When I first started programing XL15 contollers I would put in a 15C for loops. To later come back and take out after I could make things work with the 15A.

[codewriter]

The 15A is more of a challange than the 15C?

Possibly you have that backwards?

[theirb]

That is what I said.

[codewriter]

I'm still confused. I can't see how anyone would say the C is easier than the A. The A does not compare to the capabilities of the C. The C has logic functions that the A could not dream of.

edit:
What do you do for setpoints of no measurement?
What do you do for nvoapplicmode?
etc...???

[Edited by codewriter on 02-13-2006 at 09:35 PM]

[gman994]

So let's say I was setting up a control loop, and I did it the way you described, to control the cooling valves. I get the sequencer set up and move onto the output box, I assume the control valves will be setup as AO1, AO2, and AO3 (for this example anyway). When the SEQ 1 box is selected, even though it's labeled as Heat, it's configured as a cooling output , and will control as such. The 2 remaining SEQ boxes will be configured to control AO2 and AO3 respectively. Easy enough. What if I had additional devices to control? Can the EPID output box be used as another AO ? Is the EPID the X% value of the SEQ ? Now to muddy the water, what if I were setting up a simple air handler strategy using the default SEQ setings. I'd set up the Heat output (seq 1) and the Cool output (seq 3) as "STAGED". And then setup the Econ output (seq 2) as an AO to drive my damper motor. As you know, there are other variables that come into play here, such as an Enthalpy or Dry Bulb changeover point, damper min position, discharge air setpoint. What type of control strategy do you use to achieve the desired result in this instance? This is where I sometimes think I overthink it. Thanks for the guidance. ---gman

[codewriter]

Originally posted by gman994
So let's say I was setting up a control loop, and I did it the way you described, to control the cooling valves. I get the sequencer set up and move onto the output box, I assume the control valves will be setup as AO1, AO2, and AO3 (for this example anyway). When the SEQ 1 box is selected, even though it's labeled as Heat, it's configured as a cooling output , and will control as such. The 2 remaining SEQ boxes will be configured to control AO2 and AO3 respectively. Easy enough. What if I had additional devices to control? Can the EPID output box be used as another AO ? Is the EPID the X% value of the SEQ ? Now to muddy the water, what if I were setting up a simple air handler strategy using the default SEQ setings. I'd set up the Heat output (seq 1) and the Cool output (seq 3) as "STAGED". And then setup the Econ output (seq 2) as an AO to drive my damper motor. As you know, there are other variables that come into play here, such as an Enthalpy or Dry Bulb changeover point, damper min position, discharge air setpoint. What type of control strategy do you use to achieve the desired result in this instance? This is where I sometimes think I overthink it. Thanks for the guidance. ---gman

The EPID output would be a full output, meaning 0-100%.
You can use outputs as inputs to other loops to expand further.

Your correct on not being able to properly setup a AHU using all three functions with one control loop. Must have been a brain fart in india when they put (heat/econ/cool) on there.
I have never personally seen the need nor desire to even atempt it. I have used the 15C in VAV applications, but always use seperate control loops.

If you want to see a ROUGH sequence, use RapidLink and setup a unit with enthalpy, etc..., then import it into lonspec and take a look. If you do not have RapidLink, let me know, I will make a project backup and send it to you to look at.

[gman994]

codewriter,
I'm not real familiar with RapidLink, though I have setup zoning jobs in Rapidzone, and then imported them into Lonspec. After getting that accomplished, I checked out the XL15C program and found it be quite interesting. Which brings to mind, what if I want to add a zone to the RZ project that I already imported ? Do I have to recreate the the job with the updated zone, in Rapidzone, and then reimport it to Lonspec? ---gman

[codewriter]

I meant to say RapidZone.

Not sure about adding a zone, cant say that I think it would be hard to simply add it in LonSpec though. I will have to look into that.

Put in 14 hours today, and prob 16-18 tomorrow... Its bedtime!