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MELSEC-
A
12 CONTROL AUXILIARY FUNCTIONS
[3] Absolute position signal transfer procedure
(1) The outline of the absolute position signal transfer procedure
between the servo amplifier and D75P2 is shown in Fig. 12.33.
For details of communication between the servo amplifier and PLC system, refer
to the servo amplifier side instruction manual.
(2) About errors during communication
(a) A time-out that occurs during communication results in error "ABS transfer
time-out" (error code: 213).
(b) A transfer data sum error results in error "ABS transfer check sum" (error
code: 214).
For remedies, etc. at error occurrence, refer to section "14.3 List of errors".
D75P2
Servo ON signal
Transmission data ready
ABS bit0
ABS bit1
Current feed value
Machine feed valueMd.30
[RWrn+0 to 1, RWrn+8 to 9]
Servo amplifier
Current position
data
<Data transmission>
<Absolute position
detection request>
<Current position data>
ABS transfer mode
ABS request
Fig. 12.33 Absolute position signal transfer procedure
[4] Precautions during control
(1) When the absolute position detection system has been configured, absolute
position restoration must be performed at least once after power on or reset.
Also, the servo amplifier will not switch on unless absolute position restoration
is completed.
(2) For use in the absolute position detection system, the following control cannot
be performed.
Infinite length feed control in which control is performed in the given
direction only, e.g. a turntable
Control in which the movement amount from the zero point address
exceeds the Condition 1 and Condition 2 ranges given below
When performing positioning in the absolute position detection system, use
the positioning address within the range that satisfies Condition 1 and
Condition 2 given on the next page.
If the positioning address is used in the range that does not satisfy Condition 1
and Condition 2, a normal current value cannot be restored at the time of
absolute position restoration and therefore the positioning address cannot be
used in the absolute position detection system.