I have (2) PR55-34 and looking to purchase a few more units that will connect the gateway to modbus devices. First what is the difference between PR55-34 and the PR55-34M? I also want to read a float switch in addition to the modbus RTU device that will be attached to the PR55-34 device. Since it is a simple contact in the float switch I would just need to connect to the GPIO on the 900MHZ board but there are no places to do that on your board. Can I avoid buying the PR52-18DI? I have another application needing an output relay but again there isn’t a spot to connect to the GPIO pins on the board.
PR55-34 – its a wirelss-RS485 bridge. think of replacing a long wire with a wireless link.
PR55-34F – connect to any modbus slave device and set the reg you want to read and the read interval, it will read that and send over wireless to a gateway. https://ncd.io/blog/configuring-modbus-rtu-transmitter-with-node-red/
These converters do no have any GPIO.
this could be used to read a GPIO
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When wireless-RS485 bridging; can a single PR55-34 be connected to multiple slave devices?
1a. Can your Enterprise IIoT Gateway act as the wireless-RS485 master or do I another PR55-34 connected to the Gateway? -
I have a Modbus device that, unfortunately, needs a coil write to trigger new data before new data can be read from the input registers . Can the PR55-34M be configured to write to a coil and then read on a time interval? I would love to just get the RS485 converted to a NCD wireless device so I can integrate more Enterprise sensors
Thanks!
- Yes it can. it doesn’t care about the RS485 data.
- Yes Enterprise gateway
- we will need to add the write function. let me know the write function code you are using and does it need to write to that reg before every read ?
@Bhaskar
Yes the write is required before every read attempt.
Below is a manual excerpt of the loop suggested by the manufacture of the RS485 device.
write to Function code 05 Reg 0001
delay
Read from Function code 04 Reg 30201 Size 6
and
Read from Function code 04 Reg 30211 Size 6
repeat
I current use this loop with node-red and a Modbus RTU to TCP converter.