The Complete Guide to EKM Metering
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- Choosing Your Meter
- Choosing your CTs (Current Transformers)
- Choosing Enclosures or Mounts
- Choosing your Communication Converter
- 120 volts 2-wire
- 120/240 volts 3-wire
- 3-phase 3-wire
- 3-phase 4-wire
- Pulse Water and Gas
- RS-485 Twisted Pair Wire (meter data wire)
Choosing Your Meter:
Our "Smart" meters use RS-485 for communication with a computer or Push gateway. RS-485 is a powerful industrial standard which allows up to 256 of these meters to be daisy-chain connected to 1 communication device on up to 4000 feet of wire.
The meter values displayed on the LCD Screen: Meter LCD screen values
If you want to read your meters with a computer or over the internet, we recommend you read on about our Omnimeter models.
EKM Omnimeter I v.3 -- Universal kWh Meter
Our EKM Omnimeter can meter any electrical system that is commonly used in the world. It can operate on 50 or 60 Hz, 120 to 480 volts, 1-phase or 3-phase, it is accurate to 0.5%, and can meter from 100 to 5000 amps.
Click on the link to see more info about our EKM Omnimeter smart meter.
Click this link to see the Omnimeter EKM Omnimeter I v.3 spec sheet.
The Omnimeter can be configured for these voltages: 120 volt 2-wire, 230 volt 2-wire (foreign), 120/240 volt 3-wire, 3-phase 3-wire 120-400 volts, 3-phase 4-wire 120 to 480 volts.
Click the link to see a wide variety of our external current transformers.
California Type Approval: Revenue Grade Accuracy Certificate
EKM Omnimeter II UL v.3 -- UL Listed Universal kWh Meter
The Underwriters Laboratories (UL) approved version of our Universal EKM-Omnimeter. This meter is both UL and cUL (Canada UL) Listed, and has been tested to CSA standards. It can also meter any electrical system that is commonly used in the world up to 240 volts. It can operate on 50 or 60 Hz, 120 to 240 volts, 1-phase or 3-phase, it is accurate to 0.5%, and can meter from 100 to 5000 amps.
Click on the link to see more info about our EKM Omnimeter UL Listed smart meter.
Click this link to see the UL Omnimeter spec sheet.
This meter can be configured for these voltages: 120 volt 2-wire, 230 volt 2-wire (foreign), 120/240 volt 3-wire, 3-phase 3-wire 120-400 volts, 3-phase 4-wire 120 to 480 volts.
Click the link to see a wide variety of our external CTs.
EKM Omnimeter Pulse v.4 -- Pulse Counting, Relay Controlling, Universal kWh Meter
This meter has the same functionality as our other Omnimeter models but has the added capability of counting pulses from up to three pulse output devices. It also has two controllable outputs that can be used to remotely control two external relays. In other words, these outputs allow you to turn on/off things like circuits, appliances, or lights, remotely. Now you can meter nearly any circuit, count pulses from three water and/or gas meters, and control two relays remotely, all with one meter.
It can operate on 50 or 60 Hz, 120 to 480 volts, 1-phase or 3-phase, it is accurate to 0.5%, and can meter from 100 to 5000 amps.
This meter can also be configured for these voltages: 120 volt 2-wire, 230 volt 2-wire (foreign), 120/240 volt 3-wire, 3-phase 3-wire 120-400 volts, 3-phase 4-wire 120 to 480 volts.
Click the link to see more info on the EKM-Omnimeter Pulse v.4 pulse counting meter.
If you want a simple read on the face kWh meter, and don’t need to read your meters remotely, we have 3 options for you:
This basic meter is designed for 120/240v electrical systems, which are the most common residential electrical systems in the U.S. The two hot wires being read pass through the body of the meter, wires must be less than 3/8" diameter. The LCD screen will display total kWh (kilowatt hours) only and cannot be reset. The 25IDS can be easily mounted on 35mm DIN Rail.
Click on the link for more info about the EKM-25IDS submeter.
EKM-15IDS -- 120 volt
This is a basic meter for 120v electrical systems. The wires being read pass through the body of the meter. Wires must be less than 3/8" diameter. The LCD screen will display total kWh (kilowatt hours) only and the value cannot be reset. The 15IDS can be easily mounted on 35mm DIN Rail.
Click on the link for more info about the EKM-15IDS electric meter.
EKM-15E -- 120 volt
This is our most affordable meter and is designed for 120v electrical systems. It comes with one 15mm external current transformer. You can mount the CT on the wire in either direction and the red and black wire can go into either CT port (Port 1 and 3). The LCD screen will display total kWh (kilowatt hours) only and cannot be reset. The 15E can be easily mounted on 35mm DIN Rail.
The "S0" in the wiring diagram refers to the Pulse Output of this meter. The pulse output can be read and counted from up to 200 feet away to determine how many kWh have been used. This meter pulses at a rate of 1000 pulses per kWh.
This meter can also be wired to read 240 volts. To do this you must always power the meter with 120 volts. You will meter the 2 hot legs of a 240 volt system. Pass one hot leg through the CT in one direction and the other hot leg through the CT in the other direction.
Click on the link for more info about the EKM-15E energy meter.
Choosing Your Current Transformers(CTs)
When choosing CTs there are four factors that you should consider:
How many CTs do I need for my electrical system?
Use 1 CT for 120 volt (or foreign 2-wire systems).
Use 2 CTs for a 120/240V three-wire system(two hots and a neutral, with or without ground).
Use 2 CTs for 3-phase 3-wire systems(3 hots and no neutral).
Use 3 CTs for 3-phase 4-wire systems(3 hots and a neutral).
What is the wire diameter that needs to pass through the CT?
Measure the outside diameter of your wires -- This is the best way to determine which CT size to use. Going by AWG gauges can be misleading if the manufacturer uses extra thick wire insulation.
Do you want CTs that open(split core), or are closed(solid core)?
Solid Core CTs are less expensive but are a bit more difficult to install, they require that you disconnect the wires being read and slip the CT over the wire. Split Core CTs are more expensive but they very easily just snap around the wires being read. Even though the Split Core are more expensive you may save money in labor in the install with the Split Core in some cases. These CTs have a built in latch, but is a good idea to secure these CTs with a ziptie to ensure closure.
What is the maximum amperage of the system being metered?
You can use any CT as long as the amperage of your electrical system does not exceed the amperage rating of the current transformer.
It is OK to have CTs that are oversized for your wires or amperage requirements. In other words, you can have a small wire passing through a large CT and you can have a large amperage rated CT on a low amperage electrical system. The wire leads on the CTs are 2 meters in length. If you need to lengthen the leads you should expect a decrease in metering accuracy. All of our CTs have an output of 26.6 mA at full capacity.
Click the link to see our 200 to 5000 amp current transformers.
Our meters come pre-configured for use with 200 amp CTs. If you are going to use CTs with a different amperage rating you will need to change the CT ratio inside of the meter, this is done over RS-485 with our EKM Dash software. If you do not have the ability to change your CT ratio, let us know before we ship your meter to you that you would like the CT ratio inside your meters altered and we will do it for you.
Please do not run current through your CTs without a meter connected to them. If you must disconnect the meter from the CT, you should short the CT White wire to the CT Black wire until you are able to reconnect the leads to your meter.
Choosing Enclosures or Mounts:
We always recommend that you install your meter in an enclosure. If you are planning to use your own enclosure we recommend that you use a piece of 35mm DIN Rail to mount and attach the meter within the electrical box.
Watertight Enclosure Kit -- This enclosure comes with a DIN Rail Piece for mounting your meter, and has 4 plastic screws in the corners of the lid that ensure a watertight seal. You can read the meter on the face through the transparent lid. If tampering is a concern, a seal can be installed by drilling a hole through 1 or more of the corner screws and adding a seal.
Indoor Enclosure Kit -- This kit allows you to surface mount or flush mount your meter. It is a clean install and the box has threaded knock-outs for attaching conduit. The kit includes all of the necessary hardware needed and also comes with a piece of DIN Rail for mounting your meter.
Click on the link to see our meter enclosures.
Choosing your Communication Converter:
The EKM Push is by far the easiest solution if you want to read you meters over the internet. It is quite literally a plug and play solution. When connected to an Omnimeter and an internet router this device sends your meter data to the cloud where it can be accessed from anywhere via the internet. The Push system allows you to log meter data without needing to continuously run software on your computer. By the way, the Push service is completely free. If you are purchasing an Omnimeter, it is definitely the solution that we recommend.
If you would like to communicate directly with your EKM Omniumeter with a computer we have 3 options.
EKM-iSerial -- Our most highly recommended converter, this converter has many advantages - high reliability, universal access (you can read your meters from any number of computers within your building or over the internet. But again, if your intent is to read your meters over the internet we recommend the EKM Push system.
Click here: iSerial -- to see more information.
USB to RS-485 -- We have a newly redesigned USB converter that uses a much more powerful FTDI Serial converter chip. This will work with all of our meters including the faster communications of the EKM Omnimeter.
RS-232 to RS-485 Converter -- If you have a PC and have a DB-9 port on your computer. It is very simple, cheap and reliable.
Click here: RS-232 to RS-485 Converter -- to see more information on our product page.
High Voltage Wiring:
You should always turn the power off before installation and the installation should only be performed by a qualified electrician.
These meters should be installed in a protected location. Such as a sub panel or electrical enclosure. If you are planning on using your own enclosure, we supply 3” pieces of DIN rail that make for an easy install. Once your meter is properly wired, you can clip the meter to this DIN rail. We also provide indoor and outdoor meter boxes. Each meter draws less than 1 watt of power.
Our EKM-Omnimeter is just one meter model that can be used to meter a range of metering system types and amperages. Use the diagrams and videos below to demonstrate proper wiring for each electrical system.
120 Volt 2-wire or 230 Volt 2-wire (foreign) EKM-Omnimeter Wiring Diagram and Video:
120/240 Volt 3-wire (2 hots and a neutral) EKM-Omnimeter Wiring Diagram and Video:
3-phase 3-wire (3 hots only) EKM-Omnimeter Wiring Diagram and Video:
3-phase 4-wire (3 hots and a neutral) EKM-Omnimeter Wiring Diagram and Video:
Pulse Counting Electric Meter for Water and Gas:
The EKM Omnimeter Pulse v.4 - our pulse input meter for remote metering of water and gas installed as a 120/240 volt meter.
The pulse output wires go to ports 11, 12 and 13 on the meter for the 3 separate pulse inputs, all of the ground wires go to port 14. These wires can be up to 200 feet long. The relay control wires go to ports 18 and 19 on the meter for the 2 separate relay inputs, all of the ground wires go to port 17. Water and Gas Meter plumbing installation is a simple matter of inline plumbing for a qualified plumber.
Click on the link for more information on the EKM-Omnimeter Pulse v.4 Pulse Counting Electric Meter.
Click here: Pulse Output Water Meters -- for more information on the product page.
Click here: Pulse Output Gas Meters -- for more information on the product page.
The external CT electrical meters need a power connection (voltage reference wire) coming from the main lines you are metering. This can be 16 to 18 AWG stranded copper wire. The meter itself draws less than a watt of power. A 1amp inline fuse is recommended in the hot lines that power the meter. This would be a precaution to protect your meter and the voltage reference wire from spikes that might cause damage. For the voltage reference, CT wires, and communication wires: make sure when you are connecting this wire to the meter, to first back off the screw all the way then insert the wire then tighten down the screw, sometimes it is hard to notice you have the wire on the wrong side of the terminal clamp. CT Wires and Electrical wires should be protected from the elements and the sun by using electrical conduit. A meter enclosure is also recommended.
CT 1 Should be around Line 1 and the meter should also get its Line 1 voltage reference from the Line 1 wire.
CT 2 Should be around Line 2 and the meter should also get its Line 2 voltage reference from the Line 2 wire.
CT 3 Should be around Line 3 and the meter should also get its Line 3 voltage reference from the Line 3 wire
Wiring diagrams are laser printed on the body of the meter and are supplied with the spec sheet for each meter. For smart meters the meter number (S/N 000000000000) is laser marked on the face of the meter under the LCD screen.
Communications (RS-485) Installation:
RS-485 Wire -- We use twisted pair wire, you can find 4 pairs of 24 AWG twisted wire inside of a CAT5 cable. CAT5 is perfect because it is easy to find, comes in 1000 foot rolls, its cheap, and easy to pull the wire for installations. Stranded CAT5 is the best, but solid copper can also be used. Use one of the twisted pairs, then you will have some extra wires to use in the future. RS-485 allows you to daisy chain up to 256 meters together on up to 4000 feet of wire. One wire is RS-485 A+ (solid orange) and the other is RS-485 B- (white with orange). Make sure when you are connecting this wire to the meter, to first back off the screw all the way then insert the wire then tighten down the screw, sometimes it is hard to notice you have the wire on the wrong side of the terminal clamp. For very long runs in electrically noisy environments, it will be better to use shielded twisted pair wires. Some installations require a 120 ohm terminating resistor but we have not found this to be important for most installations.
For long runs (over 1000 feet): biasing resistors may also be required(470 ohm biasing resistors help to reduce noise). You should also use low impedance, shielded CAT5 or CAT6 wire for the RS-485 data wire.
Video showing how up to 256 of the communicating smart meters can be connected to one communication converter over RS-485:
Twisted pair wire connections:
EKM Push: Connect RS-485 A+ on all meters to A+ on EKM Push, Connect RS-485 B- on all meters to B- on EKM Push, GND is not necessary.
USB Converter: Our new tiny USB Converter works well with all meters, A+ connects to A+ on the meters. B- on the USB converter connects to B- on the meter.
iSerial: Connect RS-485 A+ on all meters to T+ on iSerial, Connect RS-485 B- on all meters to T- on iSerial, GND is not necessary.
RS-232 Converter: Connect RS-485 A+ on all meters to A on RS-232 Converter, Connect RS-485 B- on all meters to B on RS-232 Converter
Click on the link for more info on our RS-485 Converters.
Our 485Bee will create a wireless link and replace the wired RS-485 twisted pair link that is normally used. The 485Bee can be located anywhere along the wire. You will need at least 2 of the 485Bees in any system to create the radio link. You can have clusters of meters connected to each 485Bee. You can also use up to hundreds of these devices to create a wireless mesh network.
Click here: 485Bee -- for more information on the product page.
Plug an ethernet cable into the iSerial and into your router or LAN. Connect power to your iSerial. Type: 192.168.1.125 into the URL or your web browser (this is the default IP address). This will take you to a page that asks for your User ID and Password. Default User ID: admin Default Password: admin
For v.3 and v.4 Omnimeters, make sure the settings are: RS-485, 9600 baud, 7 data bit, even parity, 1 stop bit.
For v.2 meters, make sure the settings are: RS-485, 1200 baud, 7 data bit, even parity, 1 stop bit.
You can choose to change the default IP address if you choose, be sure to keep track of the new IP address as you will need it to read your meters with the EKM Dash and may need it in the future to access your EKM-iSerial.
Click here: iSerial User Manual -- for more information on the setup and use of the iSerial.
Reading on the Face
Click here: Electric Meter LCD Display -- for more information on the meter values that are displayed on the faces of our meters.
EKM Dash Software
Our new user-friendly software allows you to read meters which are connected to your computer, whether it be a PC, Mac, or Linux box, and whether the meter is connected directly with one of our USB to RS-485 converters, over a LAN network, over the internet with the iSerial TCP/IP to Serial Converter, or whether it pulse data from the cloud using the EKM Push system. From this application you can read all of the meter parameters, set meter numbers (addresses), set passwords, reset demand to zero, and, have meter usage logged to a file and have reports e-mailed to individual users or formatted for printing and mailing. This is a direct replacement for our legacy EKM Reader software. It features all of the same functionality and more, in a much more stable and easy to use package.
Try a free 30-day trial. Download your copy with the links below.
We continue to make adjustments to increase stability of the Dash and we plan on adding a lot more features and functionality in the future. As it is still in development, we would appreciate any feedback that you can give us on your experience with it. It will work with both our v.2, v.3, and v.4 meters.
We are offering the Dash today as a free 30-day trial. You can also purchase a $30 Registration Key that will give you unlimited and use of the unrestricted EKM Dash. After the free 30-day trial is up the software will still be usable but will lose some of its functionality, like the ability to log data or send emails. The unrestricted version provides logging of meter reads to .csv files. It also can generate automatic reports emailed to individual meter users. Once purchased, all updates to the software are free.
Setup Instructions: Instructions for setting up your EKM Dash software
Information: EKM Dash User Manual
EKM Push Data or Over RS485
If you are interested in coding your own software solution, you can either use live EKM Push data to make your own application for your customers (via our Push API), or you can interpret RS-485 data to read our meters directly. For more information please visit our Developer Portal
Communication Diagrams using the EKM Push: