Remote Modbus Meter over TCP

[fastbike]

On the MID-certified version you can only set the CT ratio once, it's supposed to be used for billing, that's to prevent users from hacking the CT ratio to lower their bill. Condolences...

Thanks, I'll take that as a life lesson. Make haste slowly etc as my late mother would say, LoL.
I've ordered another. But on the positive note I finally reconnected the cat5e cable between house and stand alone garage today. It had been "disconnected" when we had fibre installed in Dec 2020 - I allowed the contractors to use the previous one as a draw wire to pull the fibre optic cable through the conduit in exchange for tunneling under the concrete driveway. But that's another story for another day.

 

[fastbike]

On the plus side, I moved the secondary wifi router out of the house into the garage, good for WAF. And got rid of the repeater in the garage. This had the OpenEVSE, Enphase PV gateway and some other automation gear running off it. So good to simply, and the wifi router has a couple of hardwired ports so will connect remote Waveshare bridge when new CT meter arrives.

 

[wpns]

allowed the contractors to use the previous one as a draw wire to pull the fibre optic cable through the conduit

Can you use the fiber to pull a string through, and then use the string to pull the fiber and a CAT5 (or a single shielded twisted pair) back through?

 

[fastbike]

Can you use the fiber to pull a string through, and then use the string to pull the fiber and a CAT5 (or a single shielded twisted pair) back through?

The contractor used my cat5 to pull their fibre and the cat5e through, so we have fibre (from network cabinet on the street to the otp on the house - about 0.5km) and the "new" cat5e in the conduit. Today I terminated each end of the cat5e.

 

[donatasm]

Thanks for inspiration, I made a wireless bridge based on two ESP32 devices via ESP-NOW protocol, seems to be working

D

Post in thread 'Wireless solution to feed CT clamp data to hybrid inverter'

Apr 6, 2025

I did manage to implement another solution: two ESP32 based boards with RS485 converters (specifically M5Stack Atom S3 Lite + Tail485) can directly communicate wireless via ESP-NOW protocol. Here's Arduino code I used: https://github.com/yuri-rage/ESP-Now-Serial-Bridge .
Only thing necessary was to use different baud rates for connection to meter and inverter. This was suggested by @peufeu in other thread, and solves a problem of small delay introduced in communication, meter data is read out faster (higher baud rate) and send back before inverter timeout or new request. Meter...

• donatasm

• 

 

[fastbike]

Eastron came back and have offered a factory reset, but I need to pay the postage both ways. I've managed to buy another at a decent price so will try that first (being more careful this time) when it arrives. I'll send the other back at some stage.

 

[SeaGal]

Eastron came back and have offered a factory reset, but I need to pay the postage both ways.

That's good to know, thanks.

 

[saen]

They'd be confiscated at the border as they use a band already allocated for other purposes in my country. In any case I've had issues with radio links in the 433MHz band previously due to obstacles and topology at the site.
The waveshares have been shown to work in this type of setup before so it is either a particular quirk of the inverter, or some wiring issue, or a configuration issue.

So you say that in NZ you don't use home Weather stations with have same communication?
/But I see thousands of them in ecowitt map/
I guess you are in mistake.
150 meters open range is not so powerful RX/TX needs under 0.1mW

20 dBm

100.0000 mW

/compared to modern phones 2W/

 

[peufeu]

In these "free for all" frequency bands you're supposed to transmit occasionally so everyone can use it without talking over each other. The remote Modbus meter thingy is going to transmit every second, possibly more often, that would cause a lot of congestion...

Cellphones coordinate to avoid jamming each other, WiFi also allocates channels intelligently and retransmits in case of error, but these simple devices don't.

 

[fastbike]

So you say that in NZ you don't use home Weather stations with have same communication?
/But I see thousands of them in ecowitt map/
I guess you are in mistake.
150 meters open range is not so powerful RX/TX needs under 0.1mW

20 dBm

100.0000 mW

/compared to modern phones 2W/

View attachment 291203
View attachment 291208

From memory the 433MHz band is used for this type of stuff
Regs are here

Buying overseas or online

Electrical, electronics and radio/wireless products can cause interference to the radio spectrum in New Zealand. To minimise this, all products — including those bought overseas or online — must comply with standards and have compliance labels.

www.rsm.govt.nz

 

[fastbike]

So you say that in NZ you don't use home Weather stations with have same communication?
/But I see thousands of them in ecowitt map/
I guess you are in mistake.
150 meters open range is not so powerful RX/TX needs under 0.1mW

20 dBm

100.0000 mW

/compared to modern phones 2W/

View attachment 291203
View attachment 291208

Just googled and they are supplied as 433 for the local market

https://www.amazon.com.au/ECOWITT-Weather-Station-Powered-Outdoor/dp/B0D8BNR5JL?th=1

 

[fastbike]

I think the replacement meter will be delivered today - I ordered the non MID version this time

 

[fastbike]

So I've installed the new meter, configured it but still had no joy. The inverter web page was showing zero for the load. The 'scope was showing about a 10 mSec gap between the response finishing and the next request being sent out.

The fix was to go into the Waveshare device configuration and set the RS485 Conflict Time Gap to 5 mSec (had been zero).
To test this I went into the garage and started my air compressor, and left the vent valve open so the motor would not cut off. This showed up in the Grid Load value on the inverter web page when it next refreshed (5 minute cycle). I double checked that this was actually being powered by the PV/battery, due to PV output being only around 500W I checked the battery web page, this showed the discharge increasing from 1.8kW to 5kW. Success !

As an aide de memoir to future self, and for anybody else struggling with this here are the settings:

Setting	Inverter Waveshare	Meter Waveshare
IP	192.168.0.22/255.255.255.0	192.168.0.28/255.255.255.0
Gateway	192.168.0.1	192.168.0.1
Ports	502	502
Destination IP	192.168.0.28
Work Mode	TCP Server	TCP Client
Serial Settings	9600/8/None/1	38400/8/None/1
No Data Restart	Disabled	Disabled
Protocol	Modbus TCP to RTU	Modbus TCP to RTU
Instruction timeout	0	0
RS485 Conflict Time Gap	5	5

 

[fastbike]

The fix was to go into the Waveshare device configuration and set the RS485 Conflict Time Gap to 5 mSec (had been zero).
To test this I went into the garage and started my air compressor, and left the vent valve open so the motor would not cut off. This showed up in the Grid Load value on the inverter web page when it next refreshed (5 minute cycle). I double checked that this was actually being powered by the PV/battery, due to PV output being only around 500W I checked the battery web page, this showed the discharge increasing from 1.8kW to 5kW. Success !

So not quite as successful as I initially thought.
The problem is that the inverter is not expecting to see a negative load on the meter, so behaves unpredictably. The reason the meter is showing a negative load is when the PV output on the garage exceeds the house load.
I think I will need to build some logic into the middle such that when the when the net garage output (garage PV minus garage Load - including EVSE) is exporting, the man in the middle will net this off against actual house load.
So the inverter will either see zero, or total "installation" load, but never a negative load. Some reconfiguration is now required

 

[peufeu]

For Solis S5 EH1P 6K:

I had a system with 1x Solis S5 6k and 1x Fronius Primo 3k

If the Solis sees export (negative) power higher than its "Export Limit" setting for an amount of time (don't remember, maybe 20s) it will freak out and shut down.
Solution: set "Export Limit" to the max the other inverter will produce, ie about 2kW in this case. Solis inverter will no longer freak out and instead it will detect this export and use it to charge the battery.

New problem: When Solis S5 has enough sun and battery is charged, it will export up to the "Export Limit" setting, which sucks if you're supposed to run zero export.

 

[saen]

Simple solution split loads behind two smart meters.
Work without problem.

 

[fastbike]

Simple solution split loads behind two smart meters.
Work without problem.

Haha, Rewire the house and garage. Install additional 35m of 3 phase armoured 16mm cable. Rewrite firmware for inverter so it can read two meters. Etc.
All sounds pretty simple - not sure why I did not think of that.

 

[SeaGal]

For Solis S5 EH1P 6K:

I had a system with 1x Solis S5 6k and 1x Fronius Primo 3k

If the Solis sees export (negative) power higher than its "Export Limit" setting for an amount of time (don't remember, maybe 20s) it will freak out and shut down.
Solution: set "Export Limit" to the max the other inverter will produce, ie about 2kW in this case. Solis inverter will no longer freak out and instead it will detect this export and use it to charge the battery.

New problem: When Solis S5 has enough sun and battery is charged, it will export up to the "Export Limit" setting, which sucks if you're supposed to run zero export.

I must be getting old, my eyes have stopped working

 

[saen]

Haha, Rewire the house and garage. Install additional 35m of 3 phase armoured 16mm cable. Rewrite firmware for inverter so it can read two meters. Etc.
All sounds pretty simple - not sure why I did not think of that.

You definitely not understand concept.
You need just second smart meter.
My PoCo "accept return to grid but charge it as used electricity:
so that how i solve problem with 2 on-grid inverters

 

[fastbike]

You definitely not understand concept.
You need just second smart meter.
My PoCo "accept return to grid but charge it as used electricity:
so that how i solve problem with 2 on-grid inverters

I export at 17c and get charged 31c. So I would be losing 14c per kWh.
Each jurisdiction has different rules. We have no net metering, and each phase is counted separately, so exporting on 2 phases and importing on the third means I lose $$.