Pilz PSS SB HYD, Basic license - Manual (Page 202)

6-140 Modular Block System: Hydraulic Presses
Standard Function Blocks
maximum time (reaction time). The maximum reaction time when
switching on the valves can be set via the input parameter
TOn (for
both valves). If the maximum reaction time is exceeded, an error
message will be issued (output parameter
ENBL = 0 and ERR = 1) and
the valves will switch off immediately (output parameter Y1 = 0 and
Y2 = 0). A reset will be necessary (see also under “Error messages”).
- Reaction time when switching off the valve:
When switched off, the valves must reach their start position within a
maximum time (reaction time). The maximum reaction time when
switching off the valves can be set via the input parameter
TOff (for
both valves). If the maximum reaction time is exceeded, an error
message will be issued (output parameter
ENBL = 0 and ERR = 1) and
a reset will be necessary (see also under “Error messages”).
INFORMATION
SB088 is designed for dual valves. You can assume that these will have
a similar switching characteristic. This means that the reaction time for
switching on (off) both valves can be monitored through the input
parameters
TOn (TOff).
• Position is monitored via acknowledgement of the valve's position (input
parameters S1 and S2), without setting a maximum reaction time (input
parameter TOn = 0 and TOff = 0).
When monitoring the position of a valve without monitoring the reaction
time, SB088 checks that the valves leave their start position (valve de-
energised, acknowledgement present) at least once in each working
cycle (valve switching on and off). If this is not the case, SB088 will
register an error (output parameter
ENBL = 0 and ERR = 1) and the
valves will switch off immediately (output parameter Y1 = 0 and Y2 = 0).
A reset will be necessary (see also under “Error messages”).
• Monitoring the position of directional control valves
With directional control valves, the position of the valves is monitored as
they are being operated. The valves must not register their start position
while they are being operated. If the directional control valves are
correctly energised (input parameter
ON = 1) and their start position is
registered while the valve output is switched on (output parameter Y1 =
1 and Y2 = 1), SB088 immediately switches off the valve output (output
parameter Y1 = 0 and Y2 = 0) and registers a fault (output parameter
ENBL = 0 and ERR = 1). A reset will be necessary (see also under
“Error messages”).
SB088