Pilz PSS 3075-3 Series, Руководство пользователя

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Function Description
4-4 Operating Manual: PSS 3075-3 Series
Once the CPU sends a “1” signal via the system bus, the PSS will supply
24 VDC to the relevant output. The status of the outputs is displayed
through LEDs, which light as soon as a “1” signal (24 VDC) is present at
the output.
Internal diagnostic circuitry tests the function of the outputs. During each
cycle, the CPU compares the actual status of the outputs with the process
image of the outputs. Outputs that are switched on will be switched off
during each self test in order to check that the output transistors can be
switched. Outputs that are switched off will be switched on during each
self test in order to check the monitoring circuit. A test will also be carried
out to check for shorts between the outputs of a sub-slot (short circuits are
detected only when the outputs are switched on). If an error occurs, the
PSS will switch to a STOP condition, switch off the outputs and send a
message to the CPU-display.
If a plant is particularly sensitive to the pulses from the power-up test on
outputs that are switched off, individual outputs or all single-pole outputs
can be excluded from testing. This is achieved using operating system call
SB255, function 2 (see overleaf).
If you deactivate the output power-up test, please make sure you observe
the following guidelines:
NOTICE
On an output that is switched off, follow the instructions below: At a non-
critical point in the program, switch the output on and then off again for
one PSS cycle. If the output does not switch correctly, the error will be
detected and registered by the operating system. To also detect shorts
between outputs that are switched off, outputs must be switched on at an
offset of one cycle.
NOTICE
To detect whether an output has been excluded from the output test
incorrectly, or whether the output test that the user has programmed is
effective, an error simulation must be carried out on each safety-related
output during commissioning. To do this, the affected output must be
switched off (output’s diode not lit up). If you then generate a short circuit
between the output and 0 V, the desired error reaction should occur. In the
worst case, the error reaction should occur within 30 minutes.