IDEC MICROSmart FC6A Series Ladder Programming Manual page 109

CDP (Dual-Pulse Reversible Counter)
The dual-pulse reversible counter CDP has up and down pulse inputs, so the three inputs are required. The circuit for a dual-pulse
reversible counter must be programmed in the following order: preset input, up-pulse input, down-pulse input, the CDP
instruction, and a counter number C0 through C511, followed by a counter preset value from 0 to 65,535.
The preset value can be designated using a decimal constant or a data register. When a data register is used, the data of the data
register becomes the preset value.
Ladder Diagram
Preset Input
CDP C1
500
I0
Up Pulse
I1
Down Pulse
I2
I3 C1 Q1
• The preset input must be turned on initially so that the current value returns to the preset value.
• The preset input must be turned off before counting may begin.
• After the current value reaches 0 (counting down), it changes to 65,535 on the next count down.
• After the current value reaches 65,535 (counting up), it changes to 0 on the next up count.
• The counter output is on only when the current value is 0.
• When the up pulse and down pulses are on simultaneously, no pulse is counted.
Timing Chart
ON
Preset Input I0
OFF
ON
Up Pulse I1
OFF
ON
Down Pulse I2
OFF
500 501 502 501
Counter C1 Value
ON
Counter C1
OFF
Program List
Instruction
LOD
LOD
LOD
CDP
LOD
AND
OUT
• • •
500 499 0 1
• • •
FC6A S MICROS L
ERIES MART
Data
I0
I1
I2
C1
500
I3
C1
Q1
500 500
P M
ADDER ROGRAMMING ANUAL
4: B
ASIC
FC9Y-B1726
I
NSTRUCTIONS
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