When installing a system with a CT run of greater than 15m* you will need to install an external CT meter. One of the manufacturers of compatible meters is Eastron.
An external CT meter is a meter which is installed near the incoming grid supply with the CT connected to the live tail in between your grid meter and consumer unit.
The meter is responsible for working out the grid power form the current recorded. This grid power is then sent to the inverter over RS485 using a data cable of up to 1200m** from the meter to the inverter. This cable is connected to the meter port your hybrid inverter.
As the information is copied exactly from the meter to the inverter please verify the meter is reading the power correctly. If the power is not being read correctly please refer to your Eastron Meter manual or contact Eastron Technical Support.
Depending on the inverter you are using the model of Eastron Meter you need to use may change. Not all models of Eastron meter are compatible with the inverter. There are detailed articles about the exact technical specifications available in our knowledge base on the installer portal but a basic overview is below. Please be aware this list is not exhaustive however these are the models we have tested and verified. We cannot comment on the set up or compatibility of non-tested models.
Compatible Single Phase Meters:
Eastron China:
Eastron SDM120CT (120A/40mA ONLY)
Eastron Europe:
Eastron SDM120CT-M (120A/40mA ONLY)
Compatible Three-Phase Meters:
Eastron SDM630MCT (CT secondary current of 1A/5A)
Eastron SDM630MCT v2 (CT secondary current of 1A/5A)
Eastron SDM630MCT-MV (CT secondary current of 40mA)
**These three-phase meters can also be configured to work with only on phase to use with our single-phase hybrid inverters.
Using a Three-Phase Meter with a Single-Phase Inverter
Your supplier can purchase these meters directly from ourselves (with CTs included) or you can order them independently. If you plan to order the meter independently please double check all specifications are correct.
Please note some suppliers may sell the meter as a bundle including CTs whereas others may sell the CTs and meters separately. The supplied Sunsynk CTs are generally NOT compatible with Eastron Meters (excluding the 300A/5A CTs provided with the HV Inverters - these are compatible with the Eastron SDM630MCT).
Choosing the Correct CT:
The single-phase (120 series) only meters are only compatible with the Eastron 120A/40mA CT.
When using the three-phase (630 series) meters if purchased without a CT you can choose which type of CT you install based on the secondary CT current. The secondary current of the CT is the second number listed and may also be called the ‘output’ current.
For example this CT has a Primary Current of 20A and a secondary current of 100mA.
The SDM630MCT, and SDM630MCT v2 are compatible with CTs that have a secondary current of either 1A or 5A.
The SDM630MCT-MV are compatible with CTs that have a secondary current of 40mA/100mA.
The meter settings will then need to be changed to reflect the parameters of the installed CT.
Changing the Eastron Meter Settings:
The settings on the meter can be changed in order to allow the meter to perform different tasks or to allow different CTs to be used.
The 630 series Eastron Meter settings can be changed on the device. To enter the set up mode press and hold the U/I and E buttons. The default password is 1000. For details on how to change these settings and what they mean please refer to your Eastron Meter manual.
The articles we provide that display Eastron settings are based off of the SDM630MCT using a CT with a ratio of 150A/1A. If you have a different sized CT or the model labelled v2 or mV the settings will NOT be the same. We advise you to consult the manual for the meter or speak to Eastron Tech support if you require further guidance. Below is an example of our settings guide for standard use using a 150A/1A CT.
The 120 series Eastron Meter settings cannot be changed on the device itself. If the correct model of meter is selected or your supplier purchases directly from us this meter will be configured for standard use and no settings changes will be required.
To change the device settings for an alternative use the 120 series meter would have to be connected to an RS485 to USB converter and connected to a laptop that has a software provided by Eastron to allow settings changes to be made. You will need to contact Eastron Technical Support to obtain this software and instructions for its use.
Notes:
* The extendable length of a CT coil will depend on a per installation basis. This is because CT connection are very sensitive to interference. Some installations the maximum installation distance may be less than 15m at which point a CT extension meter would be required. In rare circumstances some installations may be able to extend the CT further than the stated 15m.
** An RS485 signal can be carried up to 1200m however in these circumstances specialist data cable MUST be used. If using Cat5/6 cable the maximum allowable distance is 100m however this may be lower based on the individual property levels of interference.
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