Siemens SIMATIC ET 200S Operating Instructions Manual page 76

1Count24V/100kHz
2.7 Measurement Modes
Limit-Value Monitoring
Figure 2-29
After the integration time elapses, the measured value obtained (frequency, rotational speed,
or period) is compared with the assigned limit values.
If the current measured value is under the assigned low limit (measured value <low limit), the
STS_UFLW = 1 bit is set in the feedback interface.
If the current measured value is over the assigned high limit (measured value > high limit),
the STS_OFLW = 1 bit is set in the feedback interface.
You must acknowledge these bits with the RES_STS control bit.
If the measured value is still outside or again outside the limits after acknowledgment, the
corresponding status bit is set again.
If you set the low limit at 0, you switch off dynamic monitoring of violation of the low limit
value.
Depending on the parameter assignment, the enabled digital output DO1 can be set by the
limit-value monitoring:
"Function DO1" parameter
Measured value outside the limits
Measured value under the low limit
Measured value over the high limit
In isochrone mode the output is switched at the end of measurement at time T
76
Limit-Value Monitoring
DO1 is Set ...
Measured value < low limit
OR
measured value > high limit
Measured value < low limit
Measured value > high limit
Operating Instructions, 02/2007, A5E00124867-05
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Technological Functions