Siemens SIMATIC FM 353 Manual page 165

Notes
Notes regarding special boundary conditions:
S It is evident from the above example that the acceleration moment within the
lower speed range is approximately twice the value of the same value at maxi-
mum speed. This results in optimally-timed positioning cycles. Of course, the
acceleration switchover is freely selectable in accordance within certain techno-
logical criteria. In this case the result is the value of the available motor torque
M1 or M
S In case your stepper drive features the "Current control through boost" function,
you can count on the elevated curve for determining the acceleration moment.
Any advantage from increased acceleration capability is realized from the mo-
ment curve only within the lower rpm range of the motor
(e.g. M
The following adjustments should be made:
− electrical connection
− MD37 (activation of the function)
− MD48/49 (for monitoring of boost duration, see Section 7.3.6)
S In case your stepper drive features the "Current control through PWM" function,
you can reduce the power loss converted in the motor, thereby reducing motor
heating. This is possible because the acceleration moment is not needed. It is
accomplished by reducing the motor current for idle and for constant travel
phases proportional to the load moment. An advantage of reduced heating dur-
ing constant travel becomes evident from the moment curve, particularly within
the lower rpm range of the motor.
The following adjustments should be made:
− electrical connection
− MD37 (activation of the function)
− MD50 = (M
− MD51 = (M
FM 353 Stepper Drive Positioning Module
6ES7 353-1AH01-8BG0
according to the characteristic.
b1
= 3.4 Nm − 0.6 Nm = 2.8 Nm, M
b1
(f ) : M
Load max Motor
(f = 0): M
Load Motor
unchanged).
b2
(f )) 100% (e.g. 60%)
@
max
(f = 0)) 100% (e.g. 12%)
@
Starting up
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