Outline Of Zero Point Return Control; Two Types Of Zero Point Return Control - Mitsubishi A1SD75M3 User Manual

8 ZERO POINT RETURN CONTROL

8.1 Outline of zero point return control

8.1.1 Two types of zero point return control

In "zero point return control" a position is established as the starting point (or "zero
point") when carrying out positioning control, and positioning is carried out toward that
starting point.
It is used to return a machine system at any position other than the zero point to the
zero point, such as when the power is turned ON, when the AD75 issues a "zero point
return request"*, after a positioning stop, etc.
In the AD75, the two types of controls shown below are defined as "zero point return
control", following the flow of the zero point return work.
These two types of zero point return control can be executed by setting the "zero point
return parameters", setting "Positioning start No. 9001" and "Positioning start No.
9002" prepared beforehand in the AD75 to "
ON the positioning start signal.
(1) Establish a positioning control zero point
– "Machine zero point return" (positioning start No. 9001)
(2) Carry out positioning toward the zero point
– "High-speed zero point return" (positioning start No. 9002).
* The "machine zero point return" in (1) above must always be carried out before
executing the "high-speed zero point return" in (2).
When an absolute position detection system is used, however, performing a zero
point return once at the installation of a machine eliminates the need for a "machine
zero point return" in (1) after that.
REMARK
Zero point return request *
The "zero point return request flag" ( Md.40 Status: b3) must be turned ON in the
AD75, and a machine point return must be executed in the following cases.
•
When the power is turned ON
•
OFF of the servo ON signal ( Md.116 Servo status: b1)
At the ON
•
At the OFF ON of the PLC READY signal [Y1D]
The address information stored in the AD75 cannot be guaranteed while the "zero
point return request flag" is ON.
The "zero point return request flag" turns OFF and the "zero point return complete
flag" ( Md.40 Status: b4) turns ON if the machine zero point return is executed and
is completed normally.
In the absolute position detection system, ignore the zero point return request flag.
Cd.11 Positioning start No.", and turning
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MELSEC-A