Analog differential trigger

Short description

The output is set and reset depending on a configurable threshold and a differential value.

LOGO! 9 and later versions support two data types: integer (16-bit) and float (32-bit).

Connection

Description

Input Ax

Input Ax is one of the following analog signals (integer or float):

  • AI 1:

    • LOGO! 9: AI1 to AI16 3

    • 0BA8: AI1 to AI8 4

  • AM 1:

    • LOGO! 9: AM1 to AM128

    • 0BA8: AM1 to AM64

    • 0BA7: AM1 to AM16

    • 0BA6: AM1 to AM6

  • NAI 1:

    • LOGO! 9: NAI1 to NAI128

    • 0BA7 or 0BA8: NAI1 to NAI32

  • AQ 1:

    • LOGO! 9: AQ1 to AQ16

    • 0BA8: AQ1 to AQ8

    • 0BA7: AQ1 and AQ2

  • NFAI 2:

    • LOGO! 9: NFAI1 to NFAI16

  • FAM 2:

    • LOGO! 9: FAM1 to FAM32

  • The block number of a function with analog output 1 2

Parameter

Range of values

Integer

Float

Gain

  • Analog resolution 0 - 1000: -10.00 to 10.00

  • Analog resolution 0 - 4095: -10.00 to 10.00

  • Analog resolution 0 - 10000: -10.00 to 10.00

-3.402823E38 to +3.402823E38

Offset

  • Analog resolution 0 - 1000: -10000 to 10000

  • Analog resolution 0 - 4095: -32768 to 32767

  • Analog resolution 0 - 10000: -32768 to 32767

On (On/Off threshold)

  • Analog resolution 0 - 1000: -20000 to 20000

  • Analog resolution 0 - 4095: -32768 to 32767

  • Analog resolution 0 - 10000: -32768 to 32767

Δ (Differential value for calculating the off parameter)

  • Analog resolution 0 - 1000: -20000 to 20000

  • Analog resolution 0 - 4095: -32768 to 32767

  • Analog resolution 0 - 10000: -32768 to 32767

p (Number of decimals)

0, 1, 2, 3

/

Output Q

Q is set or reset, depending on the threshold and difference values.

1 If the data type of Ax is integer and the data type of this FB is configured as float, LSC will convert Ax into 32-bit receivable float data.

2 If the data type of Ax is float and the data type of this FB is configured as integer, LSC will cut off the decimal numbers of Ax and convert it into 16-bit receivable integer data.

3 AI1 to AI16: 0 to 10 V corresponds with 0 to 1000, 0 to 4095 or 0 to 10000 (internal value).

4 AI1 to AI8: 0 to 10 V corresponds with 0 to 1000 (internal value).

0BA4:

A: Gain

Range of values: 0.00 to 10.00

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 A: Function with negative difference Delta

Timing diagram B: Function with positive difference Delta

Description of the function

The function fetches the analog signal at input Ax.

Ax is multiplied by the value of the A (gain) parameter, and the value at parameter B (offset) is added to product, i.e.

(Ax * gain) + offset = actual value of Ax.

Output Q is set or reset, depending on the set (On) threshold and difference value (Delta). The function automatically calculates the Off parameter: Off = On + Delta, whereby Delta may be positive or negative. See the calculation rule below.

Calculation rule

  • When you set a negative differential value Delta, the On threshold ≥ Off threshold, and:

    Q = 1, if the actual value Ax > On
    Q = 0, if the actual value Ax ≤ Off.
    See the timing diagram A.

  • When you set a positive differential value Delta, the On threshold < the Off threshold, and Q = 1, if:
    On ≤ the actual value Ax < Off.
    See the timing diagram B.

Particular characteristics to be noted when configuring

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

Overview