GE GFK-2958E, User Manual

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Chapter 5 Detailed Descriptions of I/O Modules
GFK-2958E RSTi-EP User Manual 168
5.14.1 Setting Up the Counter
To start a counting process at least the signal mode needs to be parameterised and a rising flank at
the bit QX8.2 (“Set SW gate”) of the control word is required.
You can define the counter functions by parameterizing: the counting mode, a primary direction
(counting up or down), the counting behavior, and the hardware gate‘s function (input gate ). In
addition, you can parameterise output setting options (comparison function, hysteresis) as well as
producing a process alarm (refer to the section,
Additional Functions Features ).
Counting Range, Count Limits
The maximum count limits are predetermined by the register size and cannot be changed.
Maximum Counting Range
Limit Value
Lower count limit – 2 147 483 648 ( – 2 31 )
Upper count limit +2 147 483 647 (2 31 – 1)
5.14.2 Counter Functions
Counting Mode
Depending on the application you can chose the counting mode:
•
Endless counting, for example, for position detection with a rotary encoder
•
1-time counting with or without primary direction, for example, for counting products up to a
maximum limit
•
Periodic counting with or without primary direction, for example, repeated identical pick-and-
place operations
For both counting modes 1-time counting and periodic counting you can parameterize the counting
range with load value and end value.
Via bit QX8.5 of the control word you can load a set value into the counting value. You can define the
set value in the second double word of the process data outputs.
Counting Direction
No primary direction
The entire counting range is available when using a counting mode without primary direction.
Primary Direction Up
The counting range is limited at the top by a parameterized end value. Starting from 0, a set value or
a parameterized load value, the counter counts until the end value -1 and is reset to the load value
with the next encoder pulse.
Primary Direction Down
The counting range is limited at the bottom by a parameterized end value. Starting from 0, a set
value or a parameterized load value, the counter counts until the end value +1 and is reset to the
load value with the next encoder input.
Gate Function: Activate / Deactivate Counter
The counter is activated and deactivated using an internal gate. If the hardware gate (HW gate) is
deactivated in the parameters, the internal gate is identical to the software gate (SW gate).
With activated hardware gate, there is a logic AND connection of SW gate and HW gate, so that the
gate functions operate exclusively on the HW gate. In this case, opening and closing of the SW gate
has an interrupting effect only.