User Manual
Chapter 4
GFK-1742F
Jan 2020
Configuration
116
5.15 Drive Disable Delay. Servo Drive Disable Delay (milliseconds). The time delay from
the time the zero-velocity command is received until the drive enable (digital servo
MCON) signal switches off. Disable Delay is effective when the Enable Drive %Q bit is
turned off or certain error conditions (Stop Mode) occur. Disable Delay should be
longer than the worst-case deceleration time of the servo from maximum speed.
Because turning OFF the Enable Drive %Q bit stops the DSM314 from commanding
the servo, there are times when the drive enable signal should stay ON. For example,
if the servo runs into an End of Travel Limit and the drive enable signal was
immediately turned OFF due to the error, the servo may continue moving until it
coasted to a stop. Thus, to allow the DSM314 to command and control a fast stop,
the Drive Disable Delay should be longer than the deceleration time of the servo
from maximum speed.
The disable delay may be used to control when torque is removed from the motor
shaft. Applications using an electro-mechanical brake generally need time for the
brake to engage prior to releasing servo torque. The delay should be set to a value
longer than the engagement time for the brake. Default: 100.
5.16 Jog Velocity. Jog Velocity (User Units/second). The velocity at which the servo moves
during a Jog operation. Jog Velocity is used by motion programs when no Velocity
command is included in the program. Jog Velocity is always used by the %AQ Move
Command (27h). Default: 1000.
5.17 Jog Acceleration. Jog Acceleration Rate (User Units/second/second). The
acceleration and deceleration rate used during Jog, Find Home, Move at Velocity,
Abort All Moves and Normal Stop operations. A Normal Stop occurs when the PLC
switches from Run to Stop or after certain programming errors (refer to Appendix
A). Jog Acceleration is used by motion programs when no Acceleration command is
included in the program. Jog Acceleration is always used by the %AQ Move
Command (27h). The value of Jog Acceleration should be set high enough to
perform satisfactorily during Abort all Moves and Normal Stop operations. Default:
10000.
Note:
A minimum value after scaling is used in the DSM314. This value is determined by the
rule: Jog Acc * (user units/counts) >= 32 counts/sec/sec.
5.18 Jog Acceleration Mode. Jog Acceleration Mode (LINEAR or S-CURVE). The
acceleration mode for Jog, Find Home, Move at Velocity, Abort All Moves and
Normal Stop operations. A Normal Stop occurs when the PLC switches from Run to
Stop or after certain programming errors (refer to Appendix A). LINEAR (constant
acceleration) causes commanded velocity to change linearly with time. S-CURVE
(jerk limited acceleration) causes commanded velocity to change more slowly than
the linear mode at the beginning and end of acceleration intervals. Motions using S-
Curve acceleration require twice the time and distance to change velocity compared
to motions using the same acceleration value with Linear acceleration. In order to
maintain equal machine cycle times, an S-Curve motion profile requires an
acceleration value (and peak motor torque) twice as large as the equivalent Linear
acceleration motion profile. Therefore, a tradeoff between motor cost and machine
cycle time may be necessary. Default: LINEAR.