Mitsubishi MELDAS MDS-C1 Instruction Manual page 237

(2) Adjusting the acceleration/deceleration time constant
Synchronous tap synchronizes the operation with the servo. Generally, the spindle takes longer to
accelerate and decelerate, so the acceleration/deceleration time constant is determined on the
spindle side. Measure the acceleration time for the S command, and set a value 1.5-fold that as
the standard value.
If the spindle maximum rotation speed is 2000r/min during synchronous tap operation, first carry
out 2000r/min acceleration/deceleration with the S command as shown below. Then, measure the
total acceleration/deceleration time in a linear, 2-step or 3-step state. The time constant for
synchronous tap operation is 450ms which is 1.5-fold 300ms.
Speed FB
Measuring the acceleration time during S command
When carrying out synchronous tap operation with a motor capable of coil
changeover, either the high-speed coil or low-speed coil is used. Fix the coil
POINT
being used, and measure the acceleration time by issuing the S command in
this case.
(3) Synchronous tap trial operation
Carry out trial operation after setting the parameters. Carry out dry operation without tapping or a
workpiece, and confirm the amount that the spindle moves in respect to the servo axis. If an alarm
occurs when there is no load, check the cause with the following table.
Troubleshooting for synchronous tap trial operation
Fault
Excessive error alarm The synchronous tap detector direction is
occurs (ALM52) set in reverse.
The motor cannot follow because the tap
time constant is too short.
Overcurrent alarm The motor cannot follow because the tap
occurs (ALM32) time constant is too short.
The speed loop gain is too high for
synchronous tap control (Is there vibration
when changing to synchronous control?)
The current loop gain is too high during
synchronous tap control.
The spindle rotation The closed loop and semi-closed loop
movement amount settings for spindle control are incorrect.
does not match the
command
The gear ratio setting is incorrect.
5. Spindle Adjustment
2000
During S
command
[r/min]
1000
0
0
Acceleration time during S command
Standard acceleration time during synchronous tap (1.5-fold)
Cause
During synchronous tap control
300 450 [ms]
Check the SP193, bit5 setting.
0 = Forward run, 1 = Reverse run
Readjust the tap time constant.
Set a value double the value for the S command.
Readjust the tap time constant.
Set a value double the value for the S command.
The SP194 setting value is too large.
Set 100% as the standard.
The SP219, SP220 setting value is too large.
Set 100% as the standard.
Check which detector's FB is being used.
Spindle ENC = full closed loop: SP193, bit0 =0
Motor PLG = semi-closed loop: SP193, bit0 =1
Check the machine gear ratio.
Number of gear teeth on spindle side : SP025 to SP028
Number of gear teeth on motor side : SP029 to SP032
5 - 27
Remedy