Tom_

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About Tom_

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  1. I will work on Q2A series Mitsubishi which seems to be around 20 years old. And wondering if I can connect directly to RS-422 (25 pin D sub) (picture below) port on the CPU module? As far as I understand from the manual this port can be accessed only by a Mitsubishi programming module (Q6CPU)? The only alternative I can see from the I/O Devices is that there is A1SJ7QC24 which I assume is used for HMI, in this case I could possibly connect to RS-485 or RS-232C channel (depending which one is free). My question is by connecting to QC24 module would I be able to make my modifications online? Thanks, Tom  
  2. Master Doesn't see Holding Register

    Answer: CB1241//CM1241 modules are legacy modules which use old version of modbus instructions (ver 2.1)
  3. Master Doesn't see Holding Register

    Dear Ragib,   I've attached the files below. Please keep in mind I've tried with different data blocks, I've tried with Custom UDTs, Tried with Array of Int, Word etc. I noticed that other working projects use Modbus_Comm_Load V2.1 and Modbus_Slave V2.1 could this be an issue?
  4. Dear Engineerds,   My Master (non siemens) doesn't see the Holding Registers of the Slave (S7-1200) plc. However the Q coils are fine and all Diagnostics don't show errors. The Hardware: S7-1200 – CPU 1215C CM PtP – CB1241 RS485 (6ES7 241-1CH30-1XB0) - Half Duplex RS584   Firmware: Modbus_Comm_Load (V3.1) Modbus_Slave (V4.0)   I've tried with various DB, UDTs and manipulating HR_Start_offset parameter with no success. Could you advise what am I possibly missing? Modbus_Comm_Load_DB_Snapshot.xlsx Modbus_Slave_DB_Snapshot.xlsx