Function description
Operating Manual PSSu K F INC
1001688-EN-09
16
4.2.5
Functions
4.2.5.1
Measure period length
The module can record the period length of the counter pulses on channel A. The period
length is the time between two rising edges at channel A. It is transferred to the process im-
age of inputs as multiple of 200 ns.
Prerequisite: This function is configured in PAS4000.
PIO
PII
Legend:
}
PIO: Process image of outputs, I/O datum: OutputData.LatchOrMeasure
}
PII: Process image of inputs, I/O datum: InputData.LatchOrMeasureDone
Key to timing diagram:
Section
Function
Procedure for PSSu in system environ-
ment B
a
Start measurement
In the user program, set OutputData.Lat-
chOrMeasure
b
Output measured value
Set status bit
Measured value is written in InputData.Lat-
chOrPeriod
The module sets InputData.LatchOrMeas-
ureDone
c
Finish measurement
In the user program, reset OutputData.Lat-
chOrMeasure
d
Ready for new measure-
ment
The module resets InputData.LatchOrMeas-
ureDone
The result of the last period length measurement remains in the process image of inputs
until the module signals a new measurement result by setting the status information. Before
the initial measurement the process image of inputs contains 0000 0000
H
or FFFF FFFF
H
.
The module issues the result of period length measurement in multiples of 200 ns.
Example:
}
The process image of inputs contains 32
H
/50
D
}
The period length is 200 ns x 50 = 10 μs
