Pilz PSSu E S INC - Manual (Page 22)

4.1 Module features
4 Function description
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4-6
Key:
 PIO: Bit 1 of the function call in the process image of outputs or I/O
data OutputData.LatchOrMeasure
 PII: Bit 1 of the status byte in the process image of inputs or I/O data
InputData.LatchOrMeasureDone
Key to timing diagram:
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 proc-
ess 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
μ
s
Section Function Procedure for PSSu in system envi-
ronment A Procedure for PSSu in system envi-
ronment B
a Start measurement In the user program, set Bit 1 of the
function call In the user program, set OutputDa-
ta.LatchOrMeasure
b Output measured value
Set status bit
Measured value is transferred into the
process image of inputs
The module sets Bit 1 of the status byte Measured value is written in InputDa-
ta.LatchOrPeriod
The module sets InputData.Latch-
OrMeasureDone
c Finish measurement In the user program, reset Bit 1 of the
function call In the user program, reset OutputDa-
ta.LatchOrMeasure
d Ready for new meas-
urement The module resets Bit 1 of the status
byte The module resets InputData.Latch-
OrMeasureDone
a
PAA
PAE
b c d