Brultech ECM-1240 questions
- Thread starter Sandpiper
- Start date
The AUX5 requires a 20ohm burden resistor if this channel is used for energy monitoring. There are also other resistors included in case MicroCTs are to be used with CH1 or CH2.
I will be posting an application for calculating the appropriate CT settings when using Micro CTs on CH1 & CH2.
Unfortunately Ray from a few posts ago used the first release of this application which we discovered to have an error. The mistake from this application caused to the issue he was experiencing yesterday.... my apologies Ray.
Paul
Sandpiper
Active Member
Paul,
Thank you so much for the responses. This is what I was looking for. In order to continue a discussion with less confusion, I have paraphrased previous responses, with the original question in BOLD and new questions after the responses.
1. Does a 240 volt circuit need to have 2 CT’s per channel or can it work with one CT?
A single CT may be used to monitor a 240V load only if the load does not make use of the neutral. This means that the current would be identical for both lines therefore there is no need to measure it a second time. Examples of a purely 240V load could be baseboard heaters, 240V well pumps, etc. If the load only uses Line1, Line2 and ground connections then it is safe to assume that it is 240V only load. If only one CT is used, care must be taken to compensate for the fact that only 1/2 of the expected current is used. For CH2 and CH2, the CT range would need to be reduced by a value of 1 which effectively doubles the sampled current value. As for the AUX channels, using a single CT for monitoring a 240V load requires setting the configuration to double the value of the sensed current. (This option will be available in the next software release. It is already resident in firmware). The problem with doing so is that this particular AUX channel will be restricted to single sensed 240V loads.
Understood. This makes sense and is what I was hoping for.
2. Can two 240 volt circuits be monitored on a single channel? Example: air handler and heat pump on a split A/C system. If so, how many Ct’s are needed and how are they wired?
The answer is yes for the AUX channels as long as all of the CTs are properly phased and the total current
does not exceed 80A. The 80A max may be increased by adding a burden resistor. They would be wired in parallel.
Nice. Again this is what I expected, other than I would expect them to be wired in series, not parallel. Is this a mistake?
3. How are the CT’s wired when monitoring multiple 120VAC circuits? Also, what is the limit when monitoring “multiple†circuits? Can I monitor nine lighting circuits on one channel?
Did you overlook this one? I have not seen any response to this in the previous posts.
4. What is the input specification for channel 5 when using for voltage or pulse inputs?
i.e. what voltage level is needed and what are the hi low trigger points and what is the input impedance?
The DC voltage level that can be monitored on AUX5 is 3.3VDC full scale. Higher voltages are acceptable as long as the proper voltage divider resistors are used. The pulse function of AUX5 is based on dry contact input.
So if I can create a signal voltage of 3 volts when my gas furnace is at full capacity and 1.5 volts at half capacity, and 0 volts when off, I can monitor my gas usage on channel 5 then, right? Are there instructions in the manual or in the setup program on how to achieve the proper calibration when used this way?
5. When monitoring multiple ECM-1240 units via Ethernet, does each unit need its own Etherbee to Ethernet adapter? What is needed to monitor multiple units via Ethernet?
One EtherBee will communicate with multiple ECM-1240. The EtherBee is setup as a coordinator (ZigBee) and the energy monitors are zigbee routers.
I am still confused, I have little knowledge of ZigBee and EtherBee. I'd prefer to have Ethernet, as all of my other equipment in the house is Ethernet. How can I talk to two units via Ethernet?
6. What software is needed to record the collected data into an Excel spreadsheet?
Some of the members of cocoontech have been kind enough to share the the software they have developed with others. Some of these have the ability to write the collected energy information to a Windows database. This data is easily imported by Excel.
OK. I appreciate all the responses there. I think I can handle that part.
Thank you so much for the responses. This is what I was looking for. In order to continue a discussion with less confusion, I have paraphrased previous responses, with the original question in BOLD and new questions after the responses.
1. Does a 240 volt circuit need to have 2 CT’s per channel or can it work with one CT?
A single CT may be used to monitor a 240V load only if the load does not make use of the neutral. This means that the current would be identical for both lines therefore there is no need to measure it a second time. Examples of a purely 240V load could be baseboard heaters, 240V well pumps, etc. If the load only uses Line1, Line2 and ground connections then it is safe to assume that it is 240V only load. If only one CT is used, care must be taken to compensate for the fact that only 1/2 of the expected current is used. For CH2 and CH2, the CT range would need to be reduced by a value of 1 which effectively doubles the sampled current value. As for the AUX channels, using a single CT for monitoring a 240V load requires setting the configuration to double the value of the sensed current. (This option will be available in the next software release. It is already resident in firmware). The problem with doing so is that this particular AUX channel will be restricted to single sensed 240V loads.
Understood. This makes sense and is what I was hoping for.
2. Can two 240 volt circuits be monitored on a single channel? Example: air handler and heat pump on a split A/C system. If so, how many Ct’s are needed and how are they wired?
The answer is yes for the AUX channels as long as all of the CTs are properly phased and the total current
does not exceed 80A. The 80A max may be increased by adding a burden resistor. They would be wired in parallel.
Nice. Again this is what I expected, other than I would expect them to be wired in series, not parallel. Is this a mistake?
3. How are the CT’s wired when monitoring multiple 120VAC circuits? Also, what is the limit when monitoring “multiple†circuits? Can I monitor nine lighting circuits on one channel?
Did you overlook this one? I have not seen any response to this in the previous posts.
4. What is the input specification for channel 5 when using for voltage or pulse inputs?
i.e. what voltage level is needed and what are the hi low trigger points and what is the input impedance?
The DC voltage level that can be monitored on AUX5 is 3.3VDC full scale. Higher voltages are acceptable as long as the proper voltage divider resistors are used. The pulse function of AUX5 is based on dry contact input.
So if I can create a signal voltage of 3 volts when my gas furnace is at full capacity and 1.5 volts at half capacity, and 0 volts when off, I can monitor my gas usage on channel 5 then, right? Are there instructions in the manual or in the setup program on how to achieve the proper calibration when used this way?
5. When monitoring multiple ECM-1240 units via Ethernet, does each unit need its own Etherbee to Ethernet adapter? What is needed to monitor multiple units via Ethernet?
One EtherBee will communicate with multiple ECM-1240. The EtherBee is setup as a coordinator (ZigBee) and the energy monitors are zigbee routers.
I am still confused, I have little knowledge of ZigBee and EtherBee. I'd prefer to have Ethernet, as all of my other equipment in the house is Ethernet. How can I talk to two units via Ethernet?
6. What software is needed to record the collected data into an Excel spreadsheet?
Some of the members of cocoontech have been kind enough to share the the software they have developed with others. Some of these have the ability to write the collected energy information to a Windows database. This data is easily imported by Excel.
OK. I appreciate all the responses there. I think I can handle that part.
beelzerob
Senior Member
[quote post='115659' date='May 29 2009, 02:41 PM']Examples of a purely 240V load could be baseboard heaters, 240V well pumps, etc. If the load only uses Line1, Line2 and ground connections then it is safe to assume that it is 240V only load.[/quote]
So, one of the circuits I have slated for measuring is, after all, a 240v well pump. So, if it goes from the well control panel to the circuit breaker box with only 3 wires, then I can guess it's line 1, line 2 and gnd, right?
That being the case, then I could save one of my mini CT's for something else, correct?
And you did indicate that the adjustment you'd have to make for using only 1 CT instead of 2 was something that would be done in the 1240 internal configuration, right? ...so that the numbers being reported by the 1240 would still be correct. In other words, that adjustment would not need to be made post-processing.
Somewhat offtopic....for a pure 240v load, is the current going from the +120 V leg into the -120 v leg? And that's why there's no neutral? If so, then wouldn't the current going through each leg be the same, and thus why would you have to double it? (ignorance speaking here)
So, one of the circuits I have slated for measuring is, after all, a 240v well pump. So, if it goes from the well control panel to the circuit breaker box with only 3 wires, then I can guess it's line 1, line 2 and gnd, right?
That being the case, then I could save one of my mini CT's for something else, correct?
And you did indicate that the adjustment you'd have to make for using only 1 CT instead of 2 was something that would be done in the 1240 internal configuration, right? ...so that the numbers being reported by the 1240 would still be correct. In other words, that adjustment would not need to be made post-processing.
Somewhat offtopic....for a pure 240v load, is the current going from the +120 V leg into the -120 v leg? And that's why there's no neutral? If so, then wouldn't the current going through each leg be the same, and thus why would you have to double it? (ignorance speaking here)
So, one of the circuits I have slated for measuring is, after all, a 240v well pump. So, if it goes from the well control panel to the circuit breaker box with only 3 wires, then I can guess it's line 1, line 2 and gnd, right?
That being the case, then I could save one of my mini CT's for something else, correct?
And you did indicate that the adjustment you'd have to make for using only 1 CT instead of 2 was something that would be done in the 1240 internal configuration, right? ...so that the numbers being reported by the 1240 would still be correct. In other words, that adjustment would not need to be made post-processing.
Somewhat offtopic....for a pure 240v load, is the current going from the +120 V leg into the -120 v leg? And that's why there's no neutral? If so, then wouldn't the current going through each leg be the same, and thus why would you have to double it? (ignorance speaking here)
[/quote]
Rob,
I have a document with diagrams that explains this. The diagrams really make it quite simple to understand. I will post it soon.
beelzerob
Senior Member
"Quite simple to understand" and "So simple Rob could understand it" are sadly, two different things. However, I'll take all the help I can get. The electrician postponed until Monday now, so I have until then to figure out how many CT's are to be used where.
I think the obvious answer is that the voltage is double. The ECM-1240 apparently treats each current input as associated with a 120V source and thus does a simple multiply to come up with the total watts used. In your case we know that you actually have 240V, so we double the current (instead of doubling the voltage) and come up with the right wattage.
It is interesting that the -1240 uses its transformer to measure the actual supply voltage to make its power measurements more accurate. However, it only takes this value on one leg. If for some reason the other phase was not the same voltage you would not get accurate results. Most houses use 240 volt split phase power, and more or less randomly attach 120V circuits to one phase or the other. If the house is perfectly balanced, there is no current flow through the neutral wire, and the voltages will be identical in each leg (though out of phase). More realistically, one phase is more heavily loaded than the other, there is significant current running through the neutral wire and the voltage in the more loaded leg will be lower than the voltage in the other leg.
I'm thinking about getting two ECM-1240's and putting one on each leg to improve my accuracy - besides, I have lots of circuits to measure anyway - now if I can get some 400A CTs...
--Bob
P.S. I apologize if any of my assumptions are incorrect and look forward to better information!
WayneW
Senior Member
Good Catch and a significant question! I wired my dual MicroCTs in parallel for my 240V loads, like it shows on page 14 of my install guide. But having sensors in parallel would imply that the ECM-1240 is reading the combined current (not voltage)
Update: I read the install guide and the CH1 & CH2 inputs are rated for333mV or 666mV full scale readings. But the Aux1-4 inputs are rated at 52mA for full scale, which would imply that the unit was actually reading the combined current of paralleled MicroCTs after all. But why doesn't my data change when I use the config program to change from 1 to 2 MicroCTs for Aux1-4? Paul?
I've updated the tenEcmServer software:
(1) tenEcmServer now connects to ECM-1220 or ECM-1240 via either RS232 or ethernet via EtherBee
(2) tenEcmCharts has been significantly enhanced.
(3) Now calculates and charts NET POWER for those selling power back to electric company
http://www.tenholder.net/tenWare2/tenEcmServer
tenholde
tenEcmServer has been updated to support two ECMs simultaneously.
http://www.tenholder.net/tenWare2/tenEcmServer
tenholde
http://www.tenholder.net/tenWare2/tenEcmServer
tenholde
Sandpiper
Active Member
Thanks tenholde. There seems to be a lot more interest in the software for the Brutech unit than for the hardware. But the software is free (thanks to you and others), and the hardware is not. But I will be delaying my purchase until I get some satisfactory answers so I don't waste my time, effort, and money. I have been monitoring the Brutech web site, and do see some positive changes from time to time with improved information, but apparantly the 1240 is still in its infancy with some bugs to work out. I will wait.....
I agree with you Sandpiper. I have a Brultech 1220.H which has never comunicated with any of my PC's satisfactorily. Unfortnately, I am in New Zealand (at the bottom of the world) so cannot send the thing back easily for replacement. It does seem that support for the 1220.H has fallen by the wayside, as my repeated emails to the company were not responded to. So I am left with a gadget on the wall with limited functionality. Perhaps I should have waited for the 1240...
Good luck getting your anwsers,
Andrew
tenholde[/quote]
Thanks tenholde. There seems to be a lot more interest in the software for the Brutech unit than for the hardware. But the software is free (thanks to you and others), and the hardware is not. But I will be delaying my purchase until I get some satisfactory answers so I don't waste my time, effort, and money. I have been monitoring the Brutech web site, and do see some positive changes from time to time with improved information, but apparantly the 1240 is still in its infancy with some bugs to work out. I will wait.....
[/quote]
Good luck getting your anwsers,
Andrew
tenholde[/quote]
Thanks tenholde. There seems to be a lot more interest in the software for the Brutech unit than for the hardware. But the software is free (thanks to you and others), and the hardware is not. But I will be delaying my purchase until I get some satisfactory answers so I don't waste my time, effort, and money. I have been monitoring the Brutech web site, and do see some positive changes from time to time with improved information, but apparantly the 1240 is still in its infancy with some bugs to work out. I will wait.....
[/quote]
Sandpiper,
What questions do you have? I am sorry, I didn't realize that you had additional questions.
Paul
Their web site still shows out of stock of the standard unit (ie Package A without the wireless radio). I for one wouldn't really want to spend a 20% premium just to get the unit now. I'd rather wait and get the less expensive non-radio version because I would hook it up via RS-232.
So until they can get the A package in stock reliably, their hardware sales may not be as high as they could be. I'm sure the general economic conditions are also keepin sales lower. I know I did not buy a unit when they first where released due to the economy. I'd still have a hard time convincing the wife to go along with this purchase right now.
So until they can get the A package in stock reliably, their hardware sales may not be as high as they could be. I'm sure the general economic conditions are also keepin sales lower. I know I did not buy a unit when they first where released due to the economy. I'd still have a hard time convincing the wife to go along with this purchase right now.
