Pilz PSSu K F INC - Manual (Page 13)

Function description
Operating Manual PSSu K F INC
1001688­EN­06 13
} Input L (input for latch pulse)
At a rising edge, the module stores the current counter value in the latch memory. The
counter continues counting; it is not stopped by the latch pulse. The module transmits
the stored value to the head module. The period length measurement may be con­
figured as an alternative to the latch function.
} Input S (status input)
The encoder's fault signal output can be connected to the status input. The module
transmits the input state to the head module with the status information.
4.1.2.2 Overflow
In both operating modes the counter can accept values from 0000 0000
H
to FFFF FFFF
H
.
} With an underflow the value drops below 0000 0000
H
and the counter continues from
FFFF FFFF
H
.
} With an overflow the value FFFF FFFF
H
is exceeded and the counter continues from
0000 0000
H
.
The overflow or underflow is signalled to the head module as status information.
The status information overflow is reset:
} if the value again falls below 0000 0000
H
(underflow).
} if 5555 0000
H
is exceeded (the lower third of the value range).
The status information underflow is reset:
} if FFFF FFFF
H
is exceeded again (overflow).
} if AAAA FFFF
H
is exceeded (the upper third of the value range).
4.1.3 Incremental encoder operating mode
The counter outputs and the output for the incremental encoder's zero pulse are connected
to the dual­pole inputs (A, B, C).
} Inputs A, B
The first channel of the encoder is connected to input A, the second to input B. The
second channel is 90° out of phase. If channel A is leading, the module counts for­
wards. If channel A is lagging, the module counts backwards (see timing diagram).
} Input C
The output for the incremental encoder's zero pulse is connected to input C. An incre­
mental encoder typically supplies one zero pulse per rotation. If the zero pulse function
is activated, the module copies the last value prior to the zero pulse into the latch
memory and passes it to the process image of inputs (see chapter entitled "Transfer
counter status via latch pulse").