QUESTION:
What is the input delay of the technology digital inputs Length Measurement, Reference Point Switch and Latch in CPU 31xC and C7 613/635?

ANSWER:
The technology digital inputs Length Measurement, Reference Point Switch and Latch have an input delay of 48µs for the technological functions "Count" and "Position".

The associated pin assignments and addresses of these digital inputs are listed below for the CPU/C7 modules.

Note:
For evaluation of these digital inputs as default inputs, the input delays that you have parameterized in the HW Config in the "Inputs" tab in Properties DI/DO.

Reference documentation:
The description is based on the following sections in the manual "CPU 31xC, Technological Functions" (Edition 05.2003), Entry ID. 12429336

Terminals for Positioning with Analog Output	Section 3.1.3
Terminals for Positioning with Digital Output	Section 4.1.3
Terminal Assignment	Section 5.2.2

The C7 devices are described in the following manuals:

SIMATIC C7-613 Control System, Edition: 03/2003	Entry ID 13125532
SIMATIC C7-635 Control System, Edition: 02/2003	Entry ID 11559312

Technology digital inputs:

• Length measurement and reference point switch

These inputs are evaluated with the "Position" function.

Table 1: Pin assignment and addresses for the Length Measurement and Reference Point Switch inputs

• Latch
  This input is evaluated with the "Count" function. The Latch input is for storing the counter value in the case of a positive edge.

Table 2: Pin assignment and addresses for the Latch inputs