第一次用这个模块，用的是PNP型24V增量编码器，外接24V电源。但在手册中看到如下信息：
Note
The circuits for the counter inputs (encoder supply, encoder signals) are
non-isolated to the ground of the CPU, that is, terminal 2 (1M) must have a
low-resistance connection to CPU ground.
If you supply the encoders externally, you must also connect the ground of this external voltage with the ground of the CPU.

这里说的意思是外接电源的M要和PS电源的M接在一起吗？请各位赐教！