Pilz PSSu E S INC 24V se - Manual (Page 17)

Function description
Operating Manual PSSu E S INC 24V se(­T)
1001380­EN­03 17
a b
PIO
L
PII
c d e
Legend:
} PIO: Bit 1 of the byte for function calls in the process image of outputs or I/O data Out­
putData.LatchOrMeasure
} L: Input L for external latch
} PII: Bit 1 of the status byte in the process image of inputs or I/O data In­
putData.LatchOrMeasureDone
Key to timing diagram:
Section Function
Procedure for PSSu in sys­
tem environment A Procedure for PSSu in sys­
tem environment B
a Activate latch
function In the user program, set Bit 1
of the function call In the user program, set Out­
putData.LatchOrMeasure
b Fill latch memory Rising edge at input L:
Counter status is transferred
to the 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 transferred
to the process image of in­
puts
The module sets Bit 1 of the
status byte
Counter status is written in
InputData.LatchOrPeriod
The module sets In­
putData.LatchOrMeas­
ureDone
d Finish latch func­
tion In the user program, reset Bit
1 of the function call In the user program, reset
OutputData.LatchOrMeasure
e Ready for new
latch function The module resets Bit 1 of
the status byte The module resets In­
putData.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.
4.1.5.3 Transfer counter status via zero pulse
The output for the incremental encoder's zero pulse is connected to input C. An incremental
encoder typically supplies one zero pulse per rotation. Using the zero pulse function it is
possible to record the last counter status before the zero pulse and transmit it via the pro­
cess image of inputs.