Unable to connect A9MEM2050 to TM221CE24R

[PauloBalbino]

HI,

 I am trying to connect A9MEM2050 to PLC TM221CE24R using the PLC serial port. On the PLC when I try to read a register like 1830 (power on off counter), I am getting CommError 255, OperError: 6. 

In terms of physical connections I am connecting pin 4 (D1) of the SL1 (PLC side) to port 23 of the A9MEM2050 and pin 5 (D0) of the SL1 (PLC side) to port 24 of the A9MEM2050.

All the other pins (common/5v) are left unconnected. I am not using any terminator resistor between PLC and A9MEM2050 (following the recommendation from the TM221 manual)

(1) TM221 embedded SL1 and embedded SL2 contains fixed internal high impedance bias network resistors (4.7 kΩ). Do not use external line termination resistors (standard 150 Ω) without additional external low impedance line polarization resistors (standard 450 Ω…650 Ω) to secure a proper idle voltage state of minimum 200 mV between the D1 and D0 data lines.

Screenshots attached with ladder example and PLC SL1 configuration

Any ideas?

Thanks,

Paulo

[Bastian_Schmitz · Accepted solution]

Please change the wires, so far I see they are crossed. Alternativ add or sub the Modbus Register Address 1830 with 1. They are two different versions available. Sometime products start with Modbus Register Address 1 and sometimes with 0. I´m not sure which is the true for the PLC and the Energymeter.

[PauloBalbino]

Physical I/O pins are correct, addressing -1 fixed the issue. Thanks