Short description

The output is set or reset depending on two configurable thresholds (hysteresis).

Connetion	Description
Input Ax	Input Ax is one of the following analog signals: AI1 to AI8 (*) AM1 to AM6 (if 0BA6) or AM1 to AM16 (if 0BA7) AN1 to AN32 (if 0BA7) AQ1 and AQ2 SAQ1 to SAQ16 (if 0BA7) The block number of a function with analog output
Parameter	A: Gain Range of values: +- 10.00 B: Zero offset Range of values: +- 10,000 On: On threshold Range of values: +- 20,000 Off: Off threshold Range of values: +- 20,000 p: Number of decimals Range of values: 0, 1, 2, 3
Output Q	Q is set or reset depending on the set thresholds.
* AI1 to AI8: 0 to 10 V corresponds with 0 to 1000 (internal value).

Parameters On and Off

The On and Off parameters can be provided by the actual value of another already-programmed function:

• Analog comparator: Ax - Ay

• Analog amplifier: Ax

• Analog multiplexer: AQ

• Analog ramp: AQ

• Mathematic instruction: AQ

• PI controller: AQ

• Up/Down counter: Cnt

For the 0BA7 devices, you can additionally use the actual values of the following already-programmed functions:

• On-delay: Ta

• Off-delay: Ta

• On-/off-delay: Ta

• Retentive on-delay: Ta

• Wiping relay(pulse output): Ta

• Edge triggered wiping relay: Ta

• Asynchronous pulse generator: Ta

• Stairway light switch: Ta

• Multiple function switch: Ta

• Stopwatch: AQ

• Analog filter: AQ

• Average value: AQ

• Max/Min: AQ

• Thresholder trigger: Fre

You select the required function by the block number.

	0BA4: A: Gain Range of values 0.00... 10.00
	0BA2, 0BA3: These parameters apply: G: Gain in [%] Range of values 0..1,000 % O: Offset Range of values ±999 On: On threshold Range of values 0..9,999 Off: Off threshold Range of values 0..9,999

Parameter p (number of decimals)

Parameter p applies only to the display of On, Off and Ax values in a message text.

Parameter p does not apply to the comparison of On and Off values. (The compare function ignores the decimal point.)

Timing diagram

Description of the function

The function reads the value of the signal at the analog input Ax.

This value is multiplied by the value of parameter A (gain). Parameter B (offset) is added to the product, hence

(Ax * Gain) + Offset = Actual value Ax.

Output Q is set or reset depending on the set threshold values. See the following calculation rule.

0BA2, 0BA3: The function is as follows: The offset parameter is added to the read analog value. The sum is multiplied by the value of the gain parameter. Value = (AI+offset)*gain Output Q is set to 1 if the calculated value exceeds the on threshold (TH high). Q is reset to 0 when the value reaches or drops below the off threshold (TH low).

Calculation rule

• If threshold (On) >= threshold (Off), then:
  Q = 1, if the actual value Ax > On
  Q = 0, if the actual value Ax <= Off.

• If threshold (On) < threshold (Off), then Q = 1, if
  On <= the actual value Ax < Off.

Particular characteristics to be noted when configuring

Refer to the help on analog block parameters in the Analog value processing section.

Note

The decimal point setting must be identical in the minimum and maximum range.

Special Functions Overview