
2.PMC SPECIFICATIONS B-63983EN/01
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2.2.10 Nonvolatile Memory Control Address (K)
This address is intended to be used in, for example, the configuration in
which the position of a movable mechanical part (such as a lathe turret)
is stored as code data (such as BCD) to nonvolatile memory to preserve
the current machine position even when the power is turned off.
#7 #6 #5 #4 #3 #2 #1 #0
K909
MWRTF2 MWRTF
On the KEEP RELAY screen, it is possible to set and display the
address of the nonvolatile memory. It is also possible for a sequence
program to read or write the address.
If the power is accidentally turned off when the turret is rotating, the
turret stops at an unexpected position and a mismatch occurs between
the current position stored in the memory and the actual turret position.
When the power is resumed and a normal operation begins, the
mismatch results in an incorrect sequence operation.
To prevent such a malfunction, make a check by using nonvolatile
memory control in a sequence program as follows:
(1) Write "1" to MWRTF for the nonvolatile memory control before
the turret starts moving.
(2) Start the turret.
(3) After the turret has stopped, reset MWRTF to "0".
(4) If the power is turned off after the turret has started, therefore,
MWRTF stays at "1".
(5) When the CNC power is turned on, MWRTF2 is set to "1"
automatically if MWRTF is "1", thus informing the sequence
program of the failure.
To sum up, the sequence program performs steps (1) to (4) and
checks for an abnormal condition, using MWRTF2. If an
abnormal condition (NWRTF2 = 1) is detected, an alarm is raised
to the operator, using a user-created alarm output program.
(6) Recognizing the alarm, the operator resets MWRTF and
MWRTF2 to "0" on the KEEP RELAY screen.
(7) After making the memory content match the actual turret position,
restart operation.