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4. SAFETY OBSERVATION FUNCTION
(3) Diagnosis with test pulses
(a) Test pulse diagnosis function
Diagnoses an error of wiring by periodically outputting off-pulses when DO1_ to DO4_ are on.
The following shows the operation sequence for when STOS (STO output) is assigned to DO1_. The
off-pulses will be outputted to DO1A and DO1B periodically when STOS (STO output) is on. DO1A
and DO1B output off-pulses at different timing, they will not output the off-pulses at the same time.
The width of off-pulses can be set with [Pr. PSD30 Output device - Test pulse off time]. Set the
parameter so that external devices are not affected by outputted off-pulses.
STOS (STO output)
DO1A
DO1B
[AL. 79.6 Output device error] occurs when an error is detected by test pulse diagnosis. Whether
each output device to execute the test pulse diagnosis or not can be set with [Pr. PSD29 Output
device - Test pulse diagnosis execution selection].
(b) Parameter setting
To the input device that is assigned by [Pr. PSD08 Output device selection DO1] to [Pr. PSD11
Output device selection DO4], set the following parameter.
Set whether each output device to execute test pulse diagnosis or not with [Pr. PSD29 Output device
- Test pulse diagnosis execution selection]. Set the off time of test pulse outputted from output
devices to [Pr. PSD30 Output device - Test pulse off time].
The achievable safety level will be affected depending on the device you use and parameter settings
of this function. Refer to section 4.1 for details.
ON
OFF
ON
OFF
ON
OFF
Parameter No.
PSD29
Output device - Test pulse diagnosis execution selection
PSD30
Output device - Test pulse off time
4 - 17
Output device - Test pulse off time
Output device - Test pulse off time
Name
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