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No. 1698 SMG-5420 - No Signals via Modbus RTU 2019-11-12

Dear Madams and Sirs,

I am trying to connect a SMG-5420 device to control unit via ModbusRTU (RS485). Seemingly, the SMG does not recognize any Signals on TX and RX. I am using the following configuration

Bd-rate: 9600 bps
Data bits: 8
Stop bits: 2
Parity: None
SMG working as TCP Server
Port 502
Connection Timeout 60s
Query Flow: TCP to Serial
Slave ID 0
Response Time: 500 ms
Send Gateway Exception: Disable

When I try to access the Modbus via EzTerm (or similar tools) and try to send

15 04 00 02 00 01 93 1E

The connection is terminated.

Trying to emulate a Com-Port via ezVSP didn't either.

Is a 120 Ohm resistor necessary for proper signal termination? What might be the reason for the Modbus Connection problems?

Best regards,

Benjamin Beck




Writer Benjamin Beck Company Nemak Wernigerode