Unable to read a SmarTest meter via MODBUSTCP

[andi6510]

What's the issue?

The communication with a Solaredge 3-Phase meter via modbus-tcp could not be established. The initial powermeter test fails because no data was received back from the meter.

Your setup

• Installation method: Python
• Storage system: Venus E Gen 2
• Power meter source: Solaredge Inverter 7E09310A-C2 connected to external 3-phase meter via RS485

Configuration

[GENERAL]
DEVICE_TYPE = shellyemg3
SKIP_POWERMETER_TEST = False
DISABLE_SUM_PHASES = False
DISABLE_ABSOLUTE_VALUES = False
POLL_INTERVAL = 1
THROTTLE_INTERVAL = 0

[MODBUS]
HOST = 192.xxx.yyy.zzz
PORT = 502
UNIT_ID = 1
ADDRESS = 206
COUNT = 5
DATA_TYPE = INT16
BYTE_ORDER = BIG
WORD_ORDER = BIG
REGISTER_TYPE = HOLDING

Error messages or logs

# Paste any error messages here (if applicable)

Additional info

after enabling debugging, I found that the unit-ID in the request packet was always 0.
So I fixed the problem by changing one line in modbus.py, line 64:
old: result = read(self.address, self.count, unit=self.unit_id)
new: result = read(self.address, self.count, self.unit_id)
With that change the unit_id in the request packet follows the value configured in config.ini.