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How to change CT polarity of PM870 MG?

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penev
Ensign
Ensign
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1079

How to change CT polarity of PM870 MG?

Hi everyone,

We use plenty of PM 870 meters in a project but all these meters have been already connected. And some of CT circuits are with wrong polarity. I did not find any way to change that, neither by display nor by ION Setup. And I can't open the VIP of these devices. It is not available. It will save me a lot of work hours if there is a secret way of changing it. Help, please.

RGDs

Viktor

17 Replies 17
sesa186702
Schneider Alumni (Retired)
Schneider Alumni (Retired)
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856

Re: How to change CT polarity of PM870 MG?

Hi Vikto,

No ways to do that. In this case, you can inform to customer cut-off load, turn off CB and change the polarity at the terminal of Power Meter 870

If your project is using shorting block for CT Terminal, you can use it, and change the polarity at the Power Meter

Regards

sesa125036_brid
Lieutenant Lieutenant
Lieutenant
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856

Re: How to change CT polarity of PM870 MG?

Hi, no way. the CT polarity will have to be changed physically. The meter does not have a firmware feature for auto correct. Thanks

JamesAZZO
Sisko | EcoXpert Master Sisko | EcoXpert Master
Sisko | EcoXpert Master

Re: How to change CT polarity of PM870 MG?

Sorry to contradict you guys above, but veryvery thankfully in a situation we had with a substation a couple years ago, we found that the PM870 does indeed have this functionality, but it's just not exposed in ION Setup or the PME driver.

We had an HV site which only gets shut down once every 3 years, and therefore it was absolutely impossible to shut down, and without shorting links, it was not possibly without losing the CTs.

For us, the VIP workaround totally defeated the purpose of the PM870's on-board logging features for 4 quadrant measurements and would effectively turn our PM870 into a PM810 with software logs only for those vector-reliant measurements. So, if that's all you can do, then by all means, try that and at least you have something.

But I can confirm that it IS indeed possible, and the reason why I knew this could be done at the time (when I was pulling my hair out as we were going to lose a LOT of money and the customer consequently), was the very strong hint contained here in the PME Diagram for the PM870 on the Diagnostics tab:

4044

It would be unreasonable to assume this device has polarity registers for both voltage inputs and current inputs with 'normal' as the default  if they could not be 'inverted'. (just like the ION 6200 for example)

But keep in mind, the PM8x family is not writing with simple R/W registers, but it's a multi-step Modbus write process. This means you have to first write something special to a specific set of registers, then write the change you want to another read/write register, and then write another register again to save the changes. (this method is described here https://powersolutionscommunity.schneider-electric.com/message/10980 and here [DEAD LINK /message/4660#4660]https://powersolutionscommunity.schneider-electric.com/message/4660)

I'm writing this from memory, so I can't give you the specifics right now, but I'm just confirming that you can indeed do it using a manual register writing process, and I will do my best tomorrow to dig up the steps that and I took on our critical PM870s to perform the change. Essentially, it's just a manual process that you can do using a tool like ModScan to write the exact registers you need.

Can someone from PQ hardware offers like or give your blessing on us posting the procedure first before we do? There may be commercial or technical reasons why this is not published or part of ION Setup or PME's driver? I just don't want to speak out of turn here, but I'm sure it's fine, as we have had no issues at all.

However, *WARNING* - this is a non-documented work-around and if you make a mistake by writing to the wrong register, or the wrong type, or order, or anything else, you can brick your PM870s and then you'll really be stuffed. I would highly recommend that you get a very experienced person doing it, and that you try it on a test-bench a number of successful times prior to trying on a production site.

sesa125036_brid
Lieutenant Lieutenant
Lieutenant

Re: How to change CT polarity of PM870 MG?

Perfect!!!! I hope this helps Abon, to resolve the problem!!!

Ramon_Delgado
Ensign Ensign
Ensign

Re: How to change CT polarity of PM870 MG?

Ok so here is the procedure, but before I post this please be advise that this is a logical phase change and it needs to be understood that if these meters get changed out or need to be rewired that this has to be undone.  I suggest that you first read registers 3257 through 3260 which is the wiring error detection this will give you some ideas as to what is actually is wrong with the wiring.  Please go to page 150 of the PM8 Reference Manual 63230-500-225A1 6/2006 and this will assist you in interpreting the register reads.  First off you will need to write 9020 to register 8000 to enter into Setup Mode on the meter.  If any of the phases are just reversed then do the following: Writing 11 to register 3220 will reverse Phase A Voltage (writing 10 will bring it back to default), 21 to register 3221 will reverse Phase B Voltage (20=default), 31 to register 3222 will reverse Phase C Voltage (30=default), 11 to register 3223 will reverse Phase A Current (10=default), 21 to register 3224 will reverse Phase B Current (20= default), 31 to register 3225 will reverse Phase C Current (30= default), 41 to register 3226 will reverse Phase N voltage (40= default).  Now if you just need to move phases around then you just need to write the default values to the appropriate registers.  As an Example if you need to swap Phase A Voltage with Phase B Voltage you would write 20 to register 3220 and 10 to register 3221.  Now the PT's wired to Phase A Voltage terminals will be read as Phase B Voltage and so forth.  Once you have made all register writes that are necessary you will then need to write 1 to register 8001 to save the settings and 9021 to register 8000 to exit from the setup mode.

dennis_meterlog
Lieutenant
Lieutenant
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856

Re: How to change CT polarity of PM870 MG?

Is there a similar solution for the CM4000?

JamesAZZO
Sisko | EcoXpert Master Sisko | EcoXpert Master
Sisko | EcoXpert Master

Re: How to change CT polarity of PM870 MG?

- the above from Ramon is precisely what we did. Still, this is not officially exposed in either ION Setup ( - any idea why?) or PME's driver for some reason. I don't know so be careful.

sesa19908
Schneider Alumni (Retired)
Schneider Alumni (Retired)

Re: How to change CT polarity of PM870 MG?

The reason to not expose this process is Liability. This change is not flagged in software or meter display. After a phase swap is performed, the physical labels on the meter do not correspond to the readings in the software or local display anymore. Meter may show 0V in phase A but in reality it could be phase C in the physical connection, not very safe... Users doing the swap are at their own risk.

sesa39069_bridg
Ensign Ensign
Ensign
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856

Re: How to change CT polarity of PM870 MG?

Absolutely agreed to your view.

Robert_Lee
Captain Captain
Captain

Re: How to change CT polarity of PM870 MG?

ION Setup was primarily designed to replace PMCU functionality and since this wasn't available to be done via that interface, I would not of added it in ION Setup.

However, fortunately we can easily add this functionality to the existing ION Setup using a simple text editor like Notepad and some knowledge about the registers.

I will illistrate how this can be done for the PM870 but the same procedure can be done for the other PM8 models or CM models if you know which registers to write and what are the available options.

Firstly, you would using Windows Explorer to locate the main ION Setup folder (usually its in either the Program FIles or Program Files (x86), Schneider Electric\ION Setup.  Next go into the Tables sub-folder and there you see a large list of folders.  Locate the one for the class of device you wish to modify (in this case it will be SQD800 for the PM8, it would be CM4000 for the CM4 series, etc.).  Next in that sub-folder you'll see a folder for each supported model (ex. PM870) and one labelled Default.  Go into the PM870 one in this case where you'll notice a number of files, one of which is SETUP.CFG.  Open up Notepad and drag the file into the Notepad window.

You should see something similar to the following:

[SetupInfo]

SetupScreens=26

Screen1=Basic Setup

Screen2=Scaling

Screen3=Clock

Screen4=Energy & Demand

Group5=2,Communications

Screen5=Comm - Onboard Serial

Screen6=Comm - ECC Card

Screen7=Front Panel Display

Screen8=Metering Standards

....

....

For this exercise, we'll just create a new setup screen called "Input Polarity", so firstly we'll need to add that to the available screens... find the last Screen# line and simply insert a new line after it and add the next Screen# line and assign it to Input Polarity.  Here I've done it for my PM870 file so those lines look like this now:

.....

Screen25=Phasor Viewer

Screen26=Meter Resets

Screen27=Input Polarity

IOConfigRegister=43073,2

.....

Next, we'll also need to increase the # of screens that are defined at the top of the file and increment the number by 1.

[SetupInfo]

SetupScreens=27

Screen1=Basic Setup

Screen2=Scaling

....

Next, we'll need to go to the bottom of the file and add a new section which will define these new setup options and how the screen should operate.  Here is how its done for the PM8 series based on what I see in the register descriptions.

[Input Polarity]
SetupNum=7
StartAddress=43220
Registers=7
Setup1=1,7,Voltage Phase A
List1=10=Normal,11=Inverted
Setup2=2,7,Voltage Phase B
List2=20=Normal,21=Inverted
Setup3=3,7,Voltage Phase C
List3=30=Normal,31=Inverted
Setup4=4,7,Current Phase A
List4=10=Normal,11=Inverted
Setup5=5,7,Current Phase B
List5=20=Normal,21=Inverted
Setup6=6,7,Current Phase C
List6=30=Normal,31=Inverted
Setup7=7,7,Neutral Current
List7=40=Normal,41=Inverted

Finally, save your changes and then click off the device then back onto to get the info to refresh and you'll see a new "Input Polarity" setup screen.

4047
When you click on the screen, it should now show you the proper configuration and ability to modify the settings.

4048

Based on what Marcelo has indicated from a liability perspective, should we even consider this to be a standard option?

sesa256952
Schneider Alumni (Retired)
Schneider Alumni (Retired)

Re: How to change CT polarity of PM870 MG?

This is really cool!

May I suggest that you repost this under something like "Adding functionality to ION Setup" or something like that.

penev
Ensign
Ensign

Re: How to change CT polarity of PM870 MG?

Very helpful answers, guys!

Thanks a lot.

JamesAZZO
Sisko | EcoXpert Master Sisko | EcoXpert Master
Sisko | EcoXpert Master

Re: How to change CT polarity of PM870 MG?

Marcelo - that's exactly the kind if warning I thought must need to be said. In any case, converting a CT to get a correct result or swapping a phase of any kind is always a temporary measure until the physical circuit can be rectified. This may be a workaround that requires some major labeling and signage at the metering point so that anyone physically going near it understands the cabling. Although I do think it that at least for the inversion, that we can easily justify this being shown in the software per my screenshot above. The essays relationship associations however are different story. If we can add this to iron set up as well, per Robert's suggestion, I think that would be great.

dennis_meterlog
Lieutenant
Lieutenant
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3
856

Re: How to change CT polarity of PM870 MG?

Thank you for this functionality. I had a customer who was going to have to schedule a shut down on a critical process line to flip the CT, this eliminated that need. Are you aware of any other meters that would have this functionality?

Thanks,

Dennis

JamesAZZO
Sisko | EcoXpert Master Sisko | EcoXpert Master
Sisko | EcoXpert Master

Re: How to change CT polarity of PM870 MG?

All ION meters have this feature, including the 6200 - which is native in the drivers (usually done in Designer or in the Vista Diagram setup page) - and to my knowledge, only the PM8x series has this in the other PowerLogic meters. Would be interesting to see if the CM3xxx or CM4xxx have this if anyone knows...

These are the meters usually installed on critical circuits that are hard to shut down anyway...

Hal_Etheridge
Janeway Janeway
Janeway
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0
856

Re: How to change CT polarity of PM870 MG?

From the modbus protocol perspective the CM3/4000, CM2000 and PM800 family of devices are all very similar to each other (I suspect that the firmware code base has the same roots for all of them).  If it works on one device type it probably works on the other (maybe with some minor changes).

NOTE:  **You need to verify this with the specific protocol document to be sure though**.

dennis_meterlog
Lieutenant
Lieutenant

Re: How to change CT polarity of PM870 MG?

I did this on 2 CM4000's and worked like a charm.