Siemens SIMOTION Function Manual page 140

Measuring Input TO - Part III
5.2 Fundamentals of Measuring Input technology object
Measurement process
A measurement is activated by the _enableMeasuringInput program command. The
enableCommand variable indicates the execution status of this command.
The control system variable indicates whether the measuring function is active. If, for example,
a positive measured edge has been selected and the measuring input is deflected, i.e. a
measuring event occurred, the system variable cannot assume the value ACTIVE until the
measuring input is no longer deflected.
The state variable is set to the value WAITING_FOR_TRIGGER. A rising edge (from 0 to 1)
or a falling edge (from 1 to 0) triggers the measuring function. The measuredEdgeMode
parameter can be used to select which type of edge will be acquired. Acquisition of both
measured edges can also be activated by means of a measurement job, in which case you
can specify in the command which edge will be acquired first, for example, first the rising edge
and then the falling edge.
The drive must be capable of evaluating the signal edge (rising, falling, or both edges) selected
by SIMOTION at the measuring input.
When the measurement result is received, the measurement position is stored. Once the
measurement has been made, the state variable is set to TRIGGER_OCCURRED, and the
measured values can be evaluated using the measuredValue1 and measuredValue2 variables
for two measured edges.
Activation/deactivation of measurement job
The measurement job remains active until the measurement result has been obtained or until
the job is terminated by a command (e.g. _disableMeasuringInput).
The measuring process must be reactivated for each new measurement.
The measuring accuracy depends on the accuracy of the hardware used. It lies in the range
of microseconds.
Table 5-4
Edges per
processing cycle
of the measuring
input TO
Rising edge
Falling edge
Both edges
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Storing the measurement results in the system variables
measuredValue1
First rising edge
First falling edge
Chronologically
the first edge
measuredValue2 Remark
--- Only the first rising edge is acquired.
(each new edge requires a new
measurement job)
--- Only the first falling edge is acquired.
(each new edge requires a new
measurement job)
Chronologically The hardware used must provide the
the second edge possibility of evaluating the edge
selected with SIMOTION (rising, falling,
or both edges) at the measuring input
(e.g. for SIMOTION D, SINAMICS S120
CU320(-2), TM1x).
Output Cams and Measuring Inputs
Function Manual, 04/2014