User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
188 Manual, 06/2014, A5E33039675
4.4.20
Analog comparator
Short description
The output is set and reset depending on the difference Ax - Ay and on two configurable
thresholds.
Symbol in LOGO!
Wiring
Description
Inputs Ax and Ay Inputs Ax and Ay are one of the following analog
signals:
• AI1 to AI8 (*)
• AM1 to AM64
• NAI1 to NAI32
• AQ1 to AQ8
• NAQ1 to NAQ16
• Block number of a function with analog output
Parameter A: gain
Range of values: -10.00 to 10.00
B: ero offset
Range of values: -10,000 to 10,000
On: on threshold
Range of values: -20,000 to 20,000
Off: off threshold
Range of values: -20,000 to 20,000
p: number of decimals
Range of values: 0, 1, 2, 3
Output Q Q is set or reset, depending on the difference Ax - Ay
and the set thresholds..
* AI1...AI8: 0...10 V corresponds with 0...1000 (internal value).
Gain and offset parameters
For more information on the gain and offset parameters, refer to topic "Calculating the gain
and offset of analog values (Page 130)".
Parameters On and Off
The actual value of another already-programmed function the on threshold On and the off
threshold Off. You can use the actual values of the following functions:
● Analog threshold trigger (Page 183) (actual value Ax)
● Analog amplifier (Page 195) (actual value Ax)
● Analog multiplexer (Page 213) (actual value AQ)
● Analog ramp (Page 216) (actual value AQ)
● Mathematic instruction (Page 227) (actual value AQ)