Siemens SIMATIC FM 453 Manual page 289

In all operating modes except Control mode, the "servo enable" signal is re-
quired for the duration of every traversing movement, irrespective of the pa-
rameter definitions. If the controller enable is not detected or is deactivated
during the movement, the "servo enable missing" message is triggered (see
Table 11-5, Class 3/No. 61).
In all operating modes except Open-loop control mode, the "controller
ready" signal is required for the duration of every traversing movement when
the parameter is active (MD37.2). If the servo ready is not detected or is
deactivated during the movement, the "servo not ready" message is triggered
(see Table 11-5, Class 3/No. 62).
Optional Signals Phase current control ("Boost" or "PWM")
for Step Drive
Via the interface signal "Boost" or "PWM" (Pulse Width Modulation), phase
current control can be used to optimize the performance of the stepper motor.
The FM 453 implements these two functions via an output. This is done by
alternate machine data selection.
The active level of the signal can be parameterized.
Signal response:
Idle
Acceleration/delay
Constant travel
The following table shows you the available machine data for parameterizing
the function.
37
37.17
37.18
37.19
48
49
50
51
Function, PWM The signal is generated as a 20 kHz frequency.
Boost function
The signal is monitored with reference to the maximum absolute and relative
active phase.
FM 453 Servo Drive / Step Drive Positioning Module
C79000-G7076-C453-01
Movement status
inactive
active
inactive
MD Designation
Control signals
Boost active
PWM active
Boost/PWM inverted
Boost duration absolute 1 ... 1,000,000 ms
Boost duration relative
Phase current travel
Phase current idle
Description of Functions
Output signal "Boost" Output signal "PWM"
pulse duty factor per
MD 51
static active
pulse duty factor per
MD 50
Value/Meaning
0: Boost function not used
1: Boost function used
0: PWM function not used
1: PWM function used
0: Signal high active
1: Signal low active
1 ... 100%
Pulse duty factor [%]
see Section 5.3.1, Dependencies
Output signal
9-89