Siemens SIMOTION Function Manual page 145

1. D4x5-2 (X142), TM17 High Feature and C240 (B1-B4) can acquire up to 2 measured values
2. Possible scaling of "servo cycle clock" down to "TO processing cycle clock" can result in
In the case of the onboard measuring inputs of D4xx, D410-2, D4x5-2 (X122/X132), CX32,
CX32-2,
CU310/310-2/320/320-2, the minimum period between two measurements is 3 position
control cycles. Measuring signals in between are not detected.
Figure 5-9
Case 1: Loss of edges in measuring equipment
Edges that result in more than 2 measured values per position control cycle are lost in the
measuring equipment. Loss of these edges is not signaled via system variable error and TO
alarm 40009.
In the case of X142, there is a separate edge counter LEC for lost edges.
Case 2: Loss of edges due to scaling of servo cycle clock down to TO processing cycle clock
Only if the "servo cycle clock" is scaled down to "TO processing cycle clock," can lost edges
be signaled via TO alarm.
Example:
Processing cycle clock measuring input TO in the IPO = 2 ms
Servo cycle clock = 1 ms
Output Cams and Measuring Inputs
Function Manual, 04/2014
per position control cycle. If more edges occur that would result in a measured value, these
will already be lost in the measuring equipment.
the measurement hardware communicating the measured values to the measuring input
TO, but these not all being made available to the user interface. Only the system variables
measuredValue1 and measuredValue2 exist.
Example:
X142: Servo cycle clock = 1 ms; processing cycle clock measuring input TO in the IPO =
2 ms.
2 x 2 edges occur in the 2 servo cycles within one IPO cycle.
⇒ Of the 2 x 2 edges, only the first two edges are entered as measured values
(1): Edge lost in measurement hardware(2): Edge lost due to cycle clock scaling
5.2 Fundamentals of Measuring Input technology object
Measuring Input TO - Part III
145