Instruction manual

Counters
890USE18300 September 2003 97
Count Direction
Input
Every falling-edge counter block needs to count in a direction—either up or down.
Using the Advantys configuration software, set the direction of the counter as a
constant value of either 0 or 1, where:
0 = an up-counter
1 = a down-counter
The inputs may come from:
a constant
a digital input from a module on the island
a digital output from the virtual module (See The Virtual Module, p. 28)
an output on the action module (See Using the Action Module as an Input to a
Block, p. 32) written to by the fieldbus master
Reset Input Every falling-edge counter action has a reset input. The reset input is a Boolean
value. A reset value of 0 returns the counter to the specified preset value. A reset
value of 1 allows the counter to continue to increment or decrement. While reset is
low, the block does not count.
The reset input can be configured to come from:
a constant
a digital input from a module on the island
a digital output from the virtual module (See The Virtual Module, p. 28)
an output on the action module (See Using the Action Module as an Input to a
Block, p. 32) written to by the fieldbus master
For example, say you have an up-counter with a preset value of 10. The counter will
start its counting sequence at 10 and will increment by 1 each time the count input
drops from 1 to 0. Suppose that the reset input drops to 0 after three counts:
The reset input causes the counter to return to the preset value (10) and to start the
up-counting process over again.
11 12 13 12
inputs
0
1
11
13
11
up-counter
preset = 10
outputs
12
reset
0
1
11
12
10
10