I have a cpu 1211c and a cm1241 that connect to a delta plc (dvp12se) by modbus tcp.

I read an write holding register in mode=0 and address like 44196 for D100.

But I can not read and write M100!

What values should I set for the mode and address parameters?

1- S7-1200 is master.

2- My slave plc is DELTA PLC. In this plc type bit memory assign as M0 to M4000 and word memory assign D0 to D9999.

3- In Delta PLCs Mxxxx and Dxxxx are independent

Hi Masood,

I might be late with the solution. but here it is 

in Delta, The Modbus Block Address for each location is given below.

1. D Memory - Start from D0 = 44097 (Holding Register)

2. M Memory - Start from M0 = 02048 (Coli Bits)

3. X Input - Start from X0 = 01025

4. Y Output - Start from Y0 = 01281

5. Timer Memory - Start from T0

    a. Bit Memory - Done Bit - 01537

    b. Word Memory - Acc Memory - 41537

6. Counter Memory - Start from C0

    a. Bit Memory - Done Bit - 05385

    b. Word Memory - Acc Memory - 45385

The above address is true for the  ES/EX/SS/SE SA/SX/SC EH PLCs