Siemens SIMODRIVE POSMO A User Manual

5
5.3 Programming the traversing blocks (only in the pos mode, P700 = 2)
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SIMODRIVE POSMO A User Manual (POS1) – 08/2013 Edition
5.3.4 Behavior of speed–controlled traversing blocks
Speed–controlled traversing blocks use the speed controller to regulate
the actual speed to the setpoint speed.
Because the actual position value/position reference value has no influ-
ence on this control, the position setpoint is set equal to an actual posi-
tion value resulting from the speed change.
If a speed–controlled traversing block is terminated by a stop command
(e.g. due to expired timer) or by an external block change and no error
is present, then:
 if the SIMODRIVE POSMO A switches to closed–loop position control,
 the actual position present after the standstill is kept according to
the controller setting.
If during a speed–controlled traversing block
 the override speed (P24) is set to zero
or
 the control word STW.5 is set to zero (intermediate stop),
then the SIMODRIVE POSMO A remains in speed control and regulates
the speed to zero, regardless of the current actual position of the axis.
From this follows:
––> If, for example, the mechanical system pushes the
drive away from the actual position opposing the maximum
possible motor current, then at the new position SIMODRIVE
POSMO A controls the actual speed to zero.
The positional shift does not affect the closed–loop control.
––> When controlling to zero speed, a minimum drift
velocity can exist due to the control, that is not evaluated by
the drive as the axis does not have a speed when averaged
over time.
If SIMODRIVE POSMO A should maintain its position at zero
speed, the speed–controlled traversing block must be ended and
closed–loop position control selected.
Note
The execution of an intermediate stop, for instance to stop the axis
temporarily at a position, is not recommended in speed–controlled
traversing blocks due to the behavior described above!
Description
What has to be
observed?
5 Description of the Functions
02.9908.04

Siemens SIMODRIVE POSMO A Specifications

General

Brand	Siemens
Model	SIMODRIVE POSMO A
Category	Engine
Language	English