Connect to Wireless RS485

I have an Wireless RS485 PR55-34 module and a Wireless USB model PR55-17A. I am having issues trying to send and receive data from the RS485 module. As I understand it, when the RS485 module is powered on, it send a "READY’ message.

I have a simple flow (Wireless Gateway → Debug). When I restart Node-Red, and then power cycle the RS485 module, I get a message displayed in the debug panel.


If I power cycle the RS485 module again, I don’t see additional messages. However, if I restart Node-Red again, then power cycle the RS485 module, I get another single message.

Is this normal behaviour? I was expecting a message every time I power cycle the RS485 module.

Once I know this is normal I will connect a Modbus power meter to it and attempt to send a “READ” instruction and receive a response. I have already put together the data to send for the “READ” instruction.

msg.payload = { data: [0x01, 0x03, 0x40, 0x00, 0x00, 0x06, 0xD2, 0x98], address: “00:13:a2:00:41:f6:8f:7a”};

Data – device address 01, instruction 03 (Read), start register 4000, read 6 registers, 0xD2 & 0x98 are the checksums
Address – the mac address of the RS485 module

Any help would be appreciated.

RS485 does send RUNpack every time its power cycle not sure why node red wont display it every time
I always recommend connecting a USB-rs485 to the rs485 wireless and verifying that its getting a message from node red.

Unfortunately I don’t have an usb-rs485 available. My only hardware on hand is the Wireless USB modem and a Modbus electricity meter. Is there anything we can do to trouble-shoot with them?


Does the message coming from the RS485 module at power up look correct?



Can you share the raw data packet? Node-red does not know this device type so it’s parsing it as a sensor type ( even though it is a modem) that’s why you are seeing this weird parsed msg.

How would I access the raw data packet? Do I need to use LabView or another utility to capture it?

This is the complete object from Debug → Output Complete Message Object