Mitsubishi Electric MELSEC-L Series, Руководство пользователя

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Chapter 5 Data Used for Positioning Control
5.6.2 Axis monitor data
Storage item Storage details
Md.20
Current feed value
The currently commanded address is stored.
(Different from the actual motor position during operation)
The current position address is stored.
If "degree" is selected as the unit, the addresses will have a ring structure for values
between 0 and 359.99999 degrees.

The OP address is stored when the machine OPR is completed.

When the current value is changed with the current value changing function, the
changed value is stored.
Refresh cycle: Operation cycle
Md.21
Machine feed value
The address of the current position according to the machine coordinates will be
stored. (Different from the actual motor position during operation)
Note that the current value changing function will not change the machine feed
value.
Under the speed control mode, the machine feed value is constantly updated
always, irrespective of the parameter setting.
The value will not be cleared to "0" at the beginning of fixed-feed control.
Even if "degree" is selected as the unit, the addresses will become a cumulative
value. (They will not have a ring structure for values between 0 and 359.99999
degrees).
However, the machine feed value is restored with cumulating the machine feed
value before the power supply OFF (the rounded value within the range of 0 to
359.99999°) to the movement amount during the power supply OFF at the
communication start with servo amplifier after the power supply ON or PLC CPU
reset.

Machine coordinates: Characteristic coordinates determined with machine
Refresh cycle: Operation cycle
Md.22
Feedrate
The speed of the operating workpiece is stored. (May be different from the actual
motor speed during operation)

During interpolation operation, the speed is stored in the following manner.
Reference axis : Composite speed or reference axis speed (Set with
Pr.20
)
Interpolation axis : 0
Refresh cycle: Operation cycle
POINT
In case of the single axis operation, "
Md.22
Feedrate
" and "
Md.28
Axis feedrate
"
are identical.
In the composite mode of the interpolation operation, "
Md.22
Feedrate
" is a
speed in a composite direction and "
Md.28
Axis feedrate
" is that in each axial
direction.