Axis Monitor Devices - Mitsubishi Electric Q Series Programming Manual

4 POSITIONING SIGNALS

4.2.1 Axis monitor devices

The monitoring data area is used by the Motion CPU to store data such as the
machine value during positioning control, the real machine value and the number of
droop pulses in the deviation counter.
It can be used to check the positioning control state using the Motion program.
The user cannot write data to the monitoring data area (except the travel value
change register).
(1) Machine value storage register (D0+20n, D1+20n)
The machine value represents the address in the mechanical coodinate system
determined by a home position returun.
This value does not change if "G92" and work coordinate system (G54 to G59)
are executed.
This value is used to process the stroke limit range and limit switch output.
(2) Real machine value storage register (D2+20n, D3+20n)
(a) This register stores the actual motor position (machine value – deviation
counter value).
(b) The "machine value" is equal to the "real machine value" in the stopped
state. (Some real machine values are changed by the servo lock force at a
motor stop.
(3) Deviation counter value (droop pulses) storage register
This register stores the difference between the machine value and real machine
value.
(4) Minor error code storage register (D6+20n) ............. Monitor device
(a) This register stores the corresponding error code (Refer to APPENDIX 1.2)
at the minor error occurrence. If another minor error occurs after error code
storing, the previous error code is overwritten by the new error code.
(b) Minor error codes can be cleared by an error reset command (M3207+20n).
(5) Major error code storage register (D7+20n) ............. Monitor device
(a) This register stores the corresponding error code (Refer to APPENDIX 1.3)
at the major error occurrence. If another major error occurs after error code
storing, the previous error code is overwritten by the new error code.
(b) Major error codes can be cleared by an error reset command (M3207+20n).
(D4+20n, D5+20n)............ Monitor device
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