User manual

Detailed descriptions of I/O modules | Digital counter module UR20-2CNT-100
154 1432790000/03/02.2014Manual u-remote
Counter functions
Overview
Counting can be carried out up or down, with the following
functions are available:
– 1-time counting, e.g. for counting products up to a maxi-
mum limit
– Continuous counting, e.g. for detecting the position with
an incremental encoder
– Periodic counting, e.g. repeated identical pick-and-place
procedures.
Through parametrizing, a counting range with a start and
stop value can be dened in the “1-time counting” and
“periodic counting” operating modes.
Parametrizable additional functions are available with the
counter in the form of the gate function, comparator, hyster-
esis and process alarm.
Primary counting direction
A primary counting direction can be predetermined for the
counter through parametrizing.
When “none” is selected, the entire counting range is avail-
able.
Countingrange
Limits Validrangeofvalues
Lower count limit –2 147 483 648 (–2
31
)
Upper count limit [phone] (2
31
–1)
Primary counting direction up
The counting range is limited at the top. Starting at 0 or the
load value, the counter counts to the parametrized end value
-1 and is reset to the load value with the next encoder pulse.
Primary counting direction down
The counting range is limited at the bottom. Starting from
a parametrized start or load value, the counter counts until
the parametrized end value +1 and is reset to the start value
with the next encoder input.
Gate function cancelling / interrupting
The counter is activated and deactivated using an inter-
nal gate (I gate). The I gate corresponds to the software
gate (SW gate). The SW gate in the application program is
opened (activated) using a 0-1 edge at the “Set SW gate”
bit in the control word. The SW gate is closed (deactivated)
once again using a 0-1 edge at the “Reset SW gate” bit.
If the I gate has been automatically closed during “1-time
counting”, it can be reopened only with a 0-1 edge at “Set
SW gate”.
Cancelling the counting process
After closing the gate and a new gate start, the counting pro-
cess starts over from the load value.
Interrupting the counting process
After closing the gate and a new gate start, the counting pro-
cess starts again from the last updated counter reading.
Upper
count limit
Lower
count limit
Load value
Gate start Gate stop Time
Counter state
0
Overrun
Underrun
Overviewofgatefunctions.
Continuous counting
In this case, counting starts with the load value.
If the upper count limit is reached during up-counting, an
additional counting pulse in the positive direction leads to
a jump to the lower count limit. Counting continues from
there.
If the lower count limit is reached during down-counting, an
additional counting pulse in the negative direction leads to
a jump to the upper count limit. Counting continues from
there.
Because of the register size, the count limits are xed and
cannot be changed.
Countingrange
Limits Validrangeofvalues
Lower count limit –2 147 483 648 (–2
31
)
Upper count limit [phone] (2
31
–1)
The status bits “Overow performed” and “Underow per-
formed” are set in the case of an overow or underow.
They remain set until they are reset with bit “Reset status
bits” in the control word.
In addition, a process alarm can be triggered if it is provided.