Hello
I am trying to establish a connection between my CR6 datalogger and a Mitsubishi FREQROL-CS80 inverter. The idea is to be able to write and read data on the inverter by using a MODBUS RTU protocol and a RS-485 standard branch. So far I have been trying to establish a connection by reading a holding register.
For this purpose, the PU-connector on the invertor will be accessed by a RJ45 cable. The RDB & SDB are connected to form the B- part, and the RDA & SDA are connected to form the A+ part of the Half-Duplex RS-485 connection. These cables are connected to the ports C1 and C2 on the data logger CR6.
Specifications on the Mitsubishi Hardware: I would like to access register 40014, which contains the current running frequency; the PU communication station number is 7; PU communication speed is 19200 bps; We have a data length of 8 bits, a stop bit length of 2 bits, a parity check at even numbers and no communication check. The protocol is set to MODBUS RTU protocol.
My code looks as follows:
'CR6 Datalogger
Public MB_res, MB_dat(10)
'Main Program
BeginProg
‘SerialOpenFormat 22 is chosen because: “Logic 1 high Even parity/two stop bits/ 8 data bits”
SerialOpen (ComC1, -19200, 22, 10, 10000, 4)
Scan (5,Sec,0,0)
ModbusMaster (MB_res, ComC1, -19200, 7, 3, MB_dat(), 14, 1, 3, 100, 2)
NextScan
EndProg
Sadly, the only effect of this code so far is that MB_res keeps increasing by one with every scan, which indicates the error count is rising by the scan rate. I would be very grateful for any kind of help, thank you in advance.
On the CR6, C1 is the minus (-) of the RS485. Try swapping the wires between C1 and C2.
Readding the frequency of the inverter is a great idea. That is what I do with any new power equipment to get the connection figured out.