Error code 240 "Manger fail to detect CT"

[Northspoon]

I recently had a Fox Hi.5.0-EG2 inverter and battery fitted. My phone app shows the error message Code 240 "fail to detect CT".

My installer thinks the setup needs a new module to connect to the CT. Any thoughts on what might give this error?

[Dave Foster]

The hybrid inverter won't operate without a CT clamp as it cannot measure and balance the loads.

The CT clamp that comes with it is connected by a 10 metre cable, the CT clamp itself clips round the live tail of your smart meter, and the other end is wired into the CT/Meter connector of the inverter.

If it is reporting the CT clamp as missing, it's most likely something has gone wrong with the wiring (the cable often breaks inside the inverter connector if the screws are tightened too much), the module itself is usually very robust.

[Northspoon]

The solar installation is new and my knowledge is limited, but the CT clamp is on the live in my meter box. The link from the inverter is wireless via LoRA. The installer came on Monday, and tried a hard wire connection, but that failed as well, so the LoRa seems it is not the reason.

My installer is waiting to get a different meter module (?) to connect at the CT end. Just thought I would ask as I like to know more about this installation.

[Dave Foster]

I doubt CT over LoRA would work, but the hard wired connection should have, personally i'd have got that working if at all possible - less things to go wrong.

If they are talking about a meter then they will replace the CT clamp with an RS485 meter that measures the power instead (such as Chint or Eastron) - they do work ok over LoRa.

[Northspoon]

Thank you very much for the help.

The reason for LoRA is because the Solar array is on a detached garage, and we didn't want to dig up the driveway.

I afraid I am a bit lost with the technical stuff. I will ask the installer for more info. I was assured the installation would work without a hard wired connection.

This is a photo of the box that has been fixed under my outdoor meter box. The CT clamp is inside that meter box.

[Northspoon]

Just thought I would ask if that photo shows a R485 meter module?

[Dave Foster]

Just thought I would ask if that photo shows a R485 meter module?

That’s a modbus CT clamp, similar in that it converts the CT clamp measurement to a modbus RTU serial data stream that can be transmitted over distance.

An RS485 meter measures the power directly a bit like a smart meter, it then encapsulates it into an RS485 packet for transmission over distance as it is a packet based system it is effectively designed to be used this way.

[Northspoon]

Thanks Dave,

Sorry for my lack of knowledge, but are you saying that what the installer has fitted is wrong and that is why I get that error code?

Stll hoping that the installer can get the system working using a LoRA link.

[Dave Foster]

I didn’t really want to speak out against your installer, a CT or meter is critical to the systems operation and must be connected securely. I have not heard of this CT clamp transmitter being used on a Foxess system, I am told the Givenergy system will work but from what you have said the error you see suggests it does not work on Foxess.

The normal configuration for a Foxess inverter where it sends it’s data over a link would be to use a Chint or Eastron meter (both listed in the installation manual) which is designed to send over a long cable or data stream (such as LoRa).

I’m sure your installer will get this sorted.