Siemens S7-300 - Page 117

Settings
10.7 Executing "Length measurement and edge detection"
FM 352 electronic cam controller
Operating Instructions, 05/2011, A5E01071724-03
117
If the setting is disabled during a length measurement, the FM 352 does not update the data.
The MSR_DONE parameter remains reset.
Edge detection
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1. Enter a value for the minimum edge distance in the parameter DB. Write and enable
machine data.
2. Set the "edge detection" function switch. This sets the MSR_DONE parameter.
3. The positive edge at input I1 starts edge detection. The results of the measurement are
updated and can be read out, and the start value of the measurement is entered; the end
value and length assume the value -1.
4. After the update, FM 352 reports the change by resetting the MSR_DONE parameter.
5. The negative edge at input I1 stops the current measurement. The FM 352 updates the
data for the end value of the measurement and length.
6. After the update, FM 352 reports the change by setting the MSR_DONE parameter. The
results of the measurement can be read out.
7. The next start of a measurement at the positive edge at I1 resets the MSR_DONE
parameter.
If the setting is disabled during edge detection, the FM 352 does not update the data. The
MSR_DONE parameter remains reset.
Data used in the channel DB
Address Name Type Start
value
Comment
25.1 MSR_DONE BOOL FALSE 1 = length measurement completed
34.0 EDGE_ON BOOL FALSE 1 = edge detection on
34.2 MSR_ON BOOL FALSE 1 = length measurement on
38.2 MSRRD_EN BOOL FALSE 1 = read measured values
112.0 BEG_VAL DINT L#0 Start value
116.0 END_VAL DINT L#0 End value
120.0 LEN_VAL DINT L#0 Length