Function description
Operating Manual PSSu K F INC
1001688-EN-09
17
4.2.5.2
Transfer counter status via latch pulse
A signal output can be connected to input L on the module for a latch pulse. The latch pulse
may come from a PLC or position switch, for example. Using the latch function it is possible
to record and transmit the counter status at the time of this latch pulse.
Prerequisite: This function is configured in PAS4000.
PIO
PII
Legend:
}
PIO: Process image of outputs, I/O datum: OutputData.LatchOrMeasure
}
L: Input L for external latch
}
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
Activate latch function
In the user program, set OutputData.Lat-
chOrMeasure
b
Fill latch memory
Rising edge at input L: Counter status is
transferred to the latch memory
c
Output counter status
Set status bit
Counter status is written in InputData.Lat-
chOrPeriod
The module sets InputData.LatchOrMeas-
ureDone
d
Finish latch function
In the user program, reset OutputData.Lat-
chOrMeasure
e
Ready for new latch func-
tion
The module resets InputData.LatchOrMeas-
ureDone
The contents of the latch memory remains in the process image of inputs until the module
signals a new memory value by setting the status information. Before the initial transfer the
process image of inputs contains 0000 0000
H
or FFFF FFFF
H.
The module always transmits the counter status when the first latch pulse occurs after the
function has started. All subsequent latch pulses are ignored until the function is completed
and reset.
