How to read %M value of M580 PLC at Modbus 1x register

[kivafishy]

Hi guys, I'm upgrading from Quantum 140CPU43412A to BMEP582040. For local PLC bus, there is BMEXBP0400 backplane and BMXNOM0200.

At the site, DCS system is reading 1x register value from the existing Quantum PLC tag address 10001. However, I'm unable to use modscan input status 1x register to retrieve value from %M address of M580 PLC. If I'm using 0x coil register at the modscan to read/write the value with %M address of M580 PLC, it has no issue at all. All the modbus communication is established using BMXNOM0200.

I conducted another testing, using modscan input status 1x register to retrieve value from %M address of M340 P342020 via PLC serial port itself. It works as what I expected. But it is not working at M580 PLC. Why?

Based on manual link: Modicon X80 - BMXNOM0200 Serial Link Module - User Manual - 09/2020. At page 162, modbus master should be able to read value from %M of PLC. Does anyone have any clue?