Siemens SIMOTION Function Manual page 150

Measuring Input TO - Part III
5.2 Fundamentals of Measuring Input technology object
The time that elapses after reaching the start of the measuring range on the axis (mechanics)
until the measured edge is evaluated at the HW input is dependent on the configuration. In
order to activate the measuring function on reaching the desired start of the measuring range
on the axis (mechanics), you must preset the start of the measuring range with the
_enableMeasuringInput or _enableMeasuringInputCylic command, depending on the axis
velocity and response time.
This procedure is the same for the end of the measuring range. Here, it is important that the
measuring function is deactivated as soon as the end of the measuring range on the axis
(mechanics) is crossed.
If no measured edge is detected in the measuring range during a single measurement, the
measuring job is aborted and a TO alarm is triggered. During cyclic measuring, each
measurement result in the measuring range is reported. However, a TO alarm is not output if
no measured edge is detected in the measuring range.
During cyclic measuring, the measurement remains active for modulo and non-modulo axes
even after the measuring range is exited, and even over several modulo cycles. The
measurement is only terminated with _disableMeasuringInput.
For non-modulo axes, the sequence in which the start and end of the measuring range are
specified is irrelevant. If the start of the measuring range is greater than the end of the
measuring range value, the two values are exchanged.
If the start of the measuring range is greater than the end of the measuring range in a modulo
axis, the measuring range is extended from the start of the measuring range over the modulo
transition of the axis to the end of the measuring range.
Figure 5-12
Dynamic measuring range
The measuring range can also be switched on or off dynamically. An activation time is allowed
for this purpose when switching on or off.
The activation time can be specified by means of the measuringRange.activationTime
configuration data element.
This time can be used, for example, to compensate for the runtimes during activation via
PROFIBUS and the drive.
The following applies here:
● Activation of the measuring range and consideration of the activation time are performed
● This means that the accuracy depends on the position control cycle clock.
150
Measuring range for modulo axes for the measuring input
on a position control granular basis.
Output Cams and Measuring Inputs
Function Manual, 04/2014