Pilz PSSu E F INC - Manual (Page 13)

Function description
Operating Manual PSSu E F INC(­T)
1001454­EN­07 13
4 Function description
4.1 Module features
4.1.1 Integrated protection mechanisms
When the PSSu E F PS1(­T) is used to supply the system, the module supply is buffered
for 20 ms if the supply voltage is interrupted.
The module detects the following errors:
} Start­up error
} Configuration error
} ST communication error
} Bus termination error
4.1.2 Function description
Module supply
} The module supply provides the module with voltage.
Inputs
} 3 dual­pole, differential inputs A, B, C for connecting an incremental encoder or an en­
coder that provides rising edges as counter pulses.
} 3 single­pole inputs referenced to earth: G, L, S, for special functions
Operating modes
} Incremental encoder
} Counter
Functions
} Period length measurement
or
} Storing the counter status in latch memory after a latch pulse or zero pulse
} Setting the counter status
The module transfers the data and status information to the head module via the module
bus. The choice of function and the function's configuration are defined via the system soft­
ware.
4.1.2.1 Functional inputs (G, L, S)
The single­pole inputs (G, L, S) are used for special functions. Inputs G and L may be con­
nected to external signal sources, e.g. to a higher order control system. If the gate signals
are generated by a non­safety­related device or if the gate inputs are connected, common
cause failures may arise. A failure mode and effects analysis must be carried out when wir­
ing the gate inputs.
} Input G (gate input)
The counter is stopped with a 1 signal. The module ignores the counter pulses at the in­
puts until a 0 signal returns.