Cam Axis Position Restoration Method; Cam Axis Position Value Per Cycle Restoration - Mitsubishi Electric MELSEC iQ-R RD78G4 User Manual

5.3

Cam Axis Position Restoration Method

Cam axis position value per cycle restoration

If "[Pr.462] Cam axis position restoration object" is set to "0: Cam axis position value per cycle restoration" when starting
synchronous control, the cam axis position value per cycle is restored based on the cam reference position and the cam axis
command position value.
Select the method for the cam reference position to be restored. The command position value when starting synchronous
control is used as the cam axis command position value.
The cam axis position value per cycle is restored by searching for the corresponding value from the beginning to the end of
the cam pattern. Set the starting point from where to search the cam pattern in "[Pr.468] Cam axis position value per cycle
(Initial setting)". (It is also possible to search the return path in a two-way cam pattern operation.)
[Md.20] Command position value
(At synchronous control start)
[Pr.463] Setting method of cam reference position
0: Previous value
1: Initial setting
value of cam
reference position
2: Command position
value
Cam axis position value per cycle
Cam axis command position value
Cam reference position
• With reciprocating cam pattern operation, if the corresponding cam axis position value per cycle is not
searched, "Cam axis position value per cycle restoration disable" (error code: 1E78H) will occur and
synchronous control will not be started.
• When starting synchronous control, the command position value may change slightly from its original
position at starting synchronous control. This is due to the readjustment of the position based on the
restored cam axis position value per cycle. This does not result in the position mismatch.
• With a feed operation cam pattern, if the corresponding cam axis position value per cycle is not found on the
first cycle, the cam reference position is changed automatically and the pattern is searched again.
• If the cam resolution is large, search processing may take a long time when synchronous control is started.
(Operation cycle 0.25 ms) Cam resolution 256: Up to approx. 0.4 ms, Cam resolution 32768: Up to approx.
7.3 ms
(Operation cycle 0.50 ms) Cam resolution 256: Up to approx. 0.2 ms, Cam resolution 32768: Up to approx.
4.8 ms
(Operation cycle 1.00 ms) Cam resolution 256: Up to approx. 0.3 ms, Cam resolution 32768: Up to approx.
3.5 ms
• When the unit of the command position value of the output axis is degree, the current value cannot be
restored within the cam stroke range across 0[degree], and "Cam axis position value per cycle restoration
disable" (error code: 1E78H) will occur. Restore the cam axis position value per cycle within the cam stroke
range of 0 to less than 360[degree].
[Md.409] Cam axis
command position
value
[Md.408] Cam reference
position
Search the cam pattern
(It is also possible to search from the middle
of the cam axis position value per cycle.)
5 ADVANCED SYNCHRONOUS CONTROL INITIAL POSITION
The cam axis position value per cycle is
restored based on the cam reference position
and cam axis command position value.
[Md.407] Cam axis position value per cycle
5.3 Cam Axis Position Restoration Method
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