Connect to Wireless RS485

Software
1

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.

{“mac”:“00:13:a2:00:41:f6:8f:7a”,“type”:19968,“nodeId”:82,“mode”:“”,“lastHeard”:1666564795430}

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.

2

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.

3

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?

Thanks

4

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

{“mac”:“00:13:a2:00:41:f6:8f:7a”,“type”:19968,“nodeId”:82,“mode”:“”,“lastHeard”:1666564795430}

Thanks

5

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.

6

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

7

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8

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

{“topic”:“sensor_mode”,“payload”:{“mac”:“00:13:a2:00:41:f6:8f:7a”,“type”:19968,“nodeId”:82,“mode”:“”,“lastHeard”:1666621229831},“_msgid”:“27898bb77671e55a”}