Mitsubishi Electric MELSEC iQ-R RD75P4, User Manual

Page: 269 / 598

7 CONTROL SUB FUNCTIONS
7.7 Absolute Position Restoration Function
267
7
Control precautions
• When an absolute position detection system is constructed, absolute position restoration must be performed at least once
after the power supply is turned on or reset. Also, the servo amplifier does not servo on unless the absolute position
restoration is completed.
• For an absolute position detection system, the OP shift function cannot be used together. If these functions are used
together, positional deviation will occur.
• Limitless-feed controls exercised only in a fixed direction, such as the one using a turntable, cannot be performed.
• Positioning cannot be performed if the movement amount from the OP address exceeds the range of the conditions 1 and
2 shown in the restrictions on movement amounts. (

Page 267 Restrictions on movement amounts)
Restrictions on movement amounts
When performing the positioning in an absolute position detection system, use the system in a range which satisfies the
following conditions 1 and 2.
In the range that does not satisfy the condition 1 and 2, positioning cannot be used in the absolute position detection system
since the proper current value cannot be provided during the absolute position restoration.
Condition 1: Number of output pulses
This condition limits the number of pulses output from the positioning module to a servo amplifier when the positioning is
performed with the OP 0 in the absolute position detection system. In the absolute position detection system, the number of
pulses within the range determined by the following calculation formula can be output to the servo amplifier.
• Max. rotation range: OP

32767 (rev)
• Detector resolution: 8192 (pulse/rev), 16384 (pulse/rev)
(-32767

Detected resolution)

(Number of output pulses)

(32767

Detected resolution)
The following table lists the number of output pulses for each detector resolution.
When the electronic gear of the servo amplifier is used, the electronic gear ratio must be considered. The actual range of the
numbers of output pulses is determined by multiplying the range of the number of output pulses above by the inverse number
of the electronic gear ratio.
Detected resolution Number of output pulses
8192 pulses -268427264 to 268427264 pulses
16384 pulses -536854528 to 536854528 pulses
Electronic gear ratio Detected resolution Range of the numbers of output pulses
1/10 times 8192 pulses -2684272640 to 2684272640 pulses
16384 pulses -5368545280 to 5368545280 pulses
20 times 8192 pulses -13421363 to 13421363 pulses
16384 pulses -26842726 to 26842726 pulses