Understanding Energy Monitoring Topics for EGX300 and EGX150

[SGMiller]

I am an IT consultant in a small office looking at the overall energy consumption of the business. I am trying to prepare time series charts of energy usage across weekdays and weekends using historical data from PowerLogic monitors installed 4 or 5 years ago.

The office has 4 power monitoring devices on 3 distribution boards and these are:

1 x EGX300 (BCPM-Model A) [for the server room]

3 x EGX150 (iEM3255)

With these devices we should be able to chart separately:

1. Server Room
2. Office Lighting
3. Rest of office (mainly high end graphics workstations)
4. External Air conditioning condensers

I am comfortable with real-time monitoring and viewing historical data in the web console, and exporting the historical data. However I have very limited knowledge of power distribution and associated terminology.

My problem is understanding which topics from the devices are the most appropriate to chart, and also which topics are common to the EGX300 and the EGX150.

I was hoping to use kWh as these are obviously closest to the figures from our energy supplier. However there is not a commonly named topic on the EGX300 and the EGX150 with values in kWh. I have tried adding values for "Real Energy (kWh)" from the EXG300 are combined with "Energy Delivered (kWh)" on the EGX 150s however I am not getting the relative order of magnitude that I am expecting i.e. the office lighting is nearly half the office workstations which intuitively seems incorrect. And the office workstations (approx 100 with big graphics cards) are less than a fifth of the server room. And the roof top condensers are only a few percent of the load in the server room when intuitively they should be disposing of perhaps a third of that energy.

My questions are:

• am I simply looking at the wrong topics in order to understand energy usage by circuit?
• What is the best way to compare data from the EXG300 and EGX150?

Many thanks for any pointers

[Romain_Polette]

Hello @SGMiller , 

EGX300 is now a very old device... you will have no more support on this data logger.

EGX150 (Link150) has no data logging feature. You cannot define a specific topic on EGX150. You must know the Modbus Register related to "Real Energy (kWh)" on the devices downstream the Link150.

This is the role of the EGX300 to attribute a topic to the devices connected to the Link150.

Energy is a cumulative value and normally aggregated by delta of values by the EGX300.

Can you help us to understand your architecture ? What are the meters connected to LinK150 and EGX300 ?

Regards, 

[Guillaume_Evrard]

I guess answer has been provided :

1 x EGX300 (BCPM-Model A)

3 x EGX150 (iEM3255)

I would suggest to deep dive in the meter modbus manual to understand the measurements....

[SGMiller]

Dear @Romain_Polette , thanks for getting back to me.

I attach an image of the power distribution schematic. It is very simple!

I also attach an image of the device list (as shown on the EGX300). You can see that two of the EGX150s are linked under the same IP address. This one and the 3rd are then presented to the EGX300 which does the data logging.

Finally, I attach an image of the topic list from one of the EGX150. You can see that there is not a "Real Energy (kWh)" topic available.

Is it possible these just need firmware updates? I suspect the firmware is unchanged from the installation 6 years ago.

Thanks,

[Romain_Polette]

Hello @SGMiller , 

I think this is expected because iEM3255 does not propose Modbus Register with "Real Energy" (Active Energy Del+Rec" or "Active Energy Del-Rec"). Only separated registers for Active Energy Delivered and Active Energy Received. 

This is why EGX300 does not integrate "Real Energy (kWh)" topic for iEM3000 meters. This is different than ""Energy Received (kWh)" and "Energy Delivered (kWh)" topics. This is expected because upstream system like PME will manage differently these 3 different topics. 

Regards,

[SGMiller]

Many thanks @Romain_Polette 

So is there any way to calculate a value for "Real Energy" from the Topics available on the iEM3255 - even approximately - so it becomes comparable with the EGX3000 and also closer to what my energy company regards as kWh usage?

Sorry, but I do not know much about power!

Thanks.

[Romain_Polette]

Hi @SGMiller , 

A clarification just in case... Link150 is not managing the topics. Topics are managed by the EGX300 depending on the devices integrated on this data logger. Because you declared iEM3255 device type, the EGX 300 will only propose the topics available for this device.

If you are sure that your Power flow is positive (mainly from source to load but can vary), then you can use EGX300 "Energy Delivered (kWh)".

If your Power flow is bidirectional => you do not have the choice to use both  "Energy Delivered (kWh)" and " "Energy Received (kWh)".

Delivered = Imported = positive power flow

Received = Exported = negative power flow

iEM3000 User Manual explains this concept of Power Flow and how is calculated Apparent Power.

Other good explanation in the the PM8000 User Manual.

Regards, 

[SGMiller]

So, In my case Energy Received is 0 (and I am confident we are only load) so I should be able to use Entergy Delivered (kWh) values from the 3 x IEM3255 as the measure of the energy usage and add to the "Real Energy (kWh)".

However the values for delivered energy seem too low as they do not give me the overall energy usage I am expecting based on my bill from the supplier. Typical values I have for a half hour time interval are:

~9 kWh "Real Energy" from the Circuits on the EGX300

~2 + ~1 + ~0.2 kWh "Energy Delivered" for the 3 circuits on iEM3255s. 

So these add up to approx. 12 kWh per half hour but I am expecting an hourly total of more like 50-70kWh per hour based on my energy Bill.

Sorry to be so basic about this!

[Romain_Polette]

Hi @SGMiller , 

A basic thing you can do is just to check the global kWh index in the front face HMI of one iEM3255.

Take some notes at hour H and H+1. You can also do the same remotely by reading the Modbus Register 3204 (INT64) or  45100 (FLOAT32).

Then make the difference between the 2 index and check if this is the expected value.

If you have some doubt, then please check the iEM3255 configuration (CT ratio, wiring mode):

https://www.productinfo.schneider-electric.com/iem3100_iem3200_iem3300/iem3100_iem3200_iem3300-serie...

You can check the config directly on the Meter HMI or by connecting the Link150+iEM3255 to our software EcoStruxure Power Commission.

Regards, 

[SGMiller]

Many thanks @Romain_Polette 

I have installed the "EcoStruxure Power Commission" as you suggested and I can see and connect to the 3 x iEM3000.

The app can't seem to see the EGX300 on the network but I don't thing this is the problem.

The two modbus registers you mentioned dont seem to be changing but I will keep an eye.

As for checking the settings (CT ratio etc) I will need to find the electrician to understand if these are incorrect as I don't know what they should be! 

However - would any of the settings on the meter affect the Energy values by a scale factor for example would an incorrect "Number of CTs" scale down the Energy readings if it was wrong?

[Romain_Polette]

Hi @SGMiller , 

EGX300 cannot be managed by EcoStruxure Power Commission (EPC).

If you can connect your iEM3000 this is a good start.

"The two modbus registers you mentioned dont seem to be changing but I will keep an eye."

=> Be sure your Modbus tool is reading the correct Register.

=> Check if your tool needs to use the Register Address. In this case, try with registers 3200 (INT64) or 45098 (FLOAT).

=> The value of the register must change. If not, it means you are not consuming any power.

"As for checking the settings (CT ratio etc) I will need to find the electrician to understand if these are incorrect as I don't know what they should be!"

=> Ratio can be known just by checking the commercial ref of the CTs.

=> Please check if the secondary of your CTs is delivering 1A or 5A max.

=> Ratio of the CT is important. If not correctly defined, power will not be correctly calculated.

=> Ratio determines the full scale of your CT. e.g. if your ratio is 250/5:

• when your load = 0A => secondary of the CT will be 0A
• when your load = 250A => secondary of the CT will be 5A

"However - would any of the settings on the meter affect the Energy values by a scale factor for example would an incorrect "Number of CTs" scale down the Energy readings if it was wrong?"

=> If your system is 3phased and your iEM meter is configured in "1PH2W", the power will be only counted on Phase 1.

=> Number of CT will affect the calculation

=> Please check the p.6 of the Instruction Sheet to know how you can wire the CT

Regards, 

[SGMiller]

@Romain_Polette  many thanks again.

I generated a Project Report in EPC and this reported that all 3 iEM3000 are

• Power System Type 3PH4W
• CT ratio 5:5

The only curious thing is if I connect to the device in the switchboard view of EPC I get the values shown in the attachment (for one device). This panel does not explicitly give "Ct ratio", Is the CT Ratio the bottom two figures i.e. "CT Primary (A)" : "CT Secondary Type (A)"?

I think the next step is that I will get an electrician to go over the values with me and check everything is as expected.

Thank you for all your help, 

[Romain_Polette]

Hello @SGMiller , 

The settings seem good for me.
On the right column (device settings) you can see that your CT Ration set up on the iEM3255 is 250/5. Just confirm that the real CT ration is 250 A on Primary and 5A on secondary.

Regards, 

[SGMiller]

Hi @Romain_Polette 

Just a quick follow up for your information.

I had had an electrician look at the meters and at the data I am collecting.

We noted that on one Link 150 the Power Values for phase A and C did not seem to be correct as they are not proportional to the Load Currents (see attachment). The conclusion is there is an error in the internal Power calculation causing the "Energy Delivered kWh" value to be way too low.

As a workaround I am going back to the Current and Voltage readings which seem to be in right area. Using the simple formula

(Ia x Van + Ib x Vbn + Ic x Vcn)/1000 gives me a Power value in KWh which seems more in line with the values I expect.

As a side note I have updated the Firmware on the 2 Link 150s to the latest version. I hoped this would reset the registers but it seems not.

Thats it. Thankyou for all your assistance.

[Romain_Polette]

Hello @SGMiller , 

Please check the wiring of the iEM3255 CTs. The power flow seems not correct. The Power Factor is also very bad (0.425 lagging). !

This is not matching with your loads.

Regards, 

[Gopi86]

Hello @Romain_Polette I want to connect and fetch the data for some power meters(PM2230) from EGX150.  Could you please help me how to do mapping? Which software need to be use?