Pilz PSS SB HYD, Basic license - Manual (Page 46)

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Intended Use
Modular Block System: Hydraulic Presses
SB089: Sequential driving/monitoring the position of two hydraulic valves (poppet
valve and directional control valves)
SB089 is a standard function block which is designed for the sequential
drive and position monitoring of two hydraulic valves. The two valves may
be driven individually. However, only one valve may be switched on at a
time. Each valve is interlocked with respect to the other. The position of
each valve is acknowledged via a separate input.
Features:
• Input for selecting the valve type (poppet valve/directional control valve)
• Controls and monitors two valves (structurally separated valves also)
• Valves switched on in start position only
• Operation with or without reaction time monitoring
• An error message is issued if the valve is in the wrong position
• Valve is immediately switched off if an error occurs
• Reset latch when an error is detected
INFORMATION
• If both valve signals are acknowledged via switches, the supply to these
switches must be from test pulses.
• If both valve signals are acknowledged via proximity switches which
cannot be pulsed, the signal lines of the proximity switches must be laid
in different multicore cables within the duct. This will ensure that a short
cannot occur between the two signal lines.
This safety precaution will not be necessary if you use proximity switches
with diverse signals.
• Both valves are monitored via a single time parameter for switch-on and
switch-off. If you are using structurally separated valves, make sure that
these have a similar switching characteristic.