Siemens SIMATIC S7-300 Manual page 226

Description of Functions
9.3.10 Measured values
Activating the
A "length measurement" or "inprocess measurement" can be activated by
measurement
calling FC 2 and job no. 10 "single functions".
function
Since both functions use the same digital input of the FM 354, only one func-
tion can be executed at a time. In double activations, both functions are
switched to inactive. An error message is issued.
Reading out the
You can read out measured values from the FM 354, in the results from the
measurement
execution of the "length measurement" and "inprocess measurement" func-
function tions, by calling FC 5.
Prerequisites The following prerequisites must be fulfilled in order to execute the function
"measurement":
1. Connect a bounce-free switching-signal encoder (touch probe) to a digital
2. Parameterize Measurement for this input in MD34.
Function Measurement functions can be executed in all modes. An executed measure-
description ment is signaled by the checkback signal "ME" and optionally also by a pro-
cess interrupt.
Inprocess measurement
The present actual position is captured at each rising edge of the touch probe.
At the same time, the axis movement is interrupted (servo-controlled brak-
ing).
Measurement taking place
Inprocess Measurement On
Measurement input
Process interrupt
S1 – execution of measurement
9-50
output of the FM 354.
S1
FM 354 Servo Drive Positioning Module