Hello all,

to compare constant values (with amount smaller 19999) with an analog value are neededneeded again and again and can be carried out efficient by means of a block Of "analogous threshold trigger". In the following one my generally applicable variants for the testing of analog values Ax concerning a fixed comparative value of n (for example also n = 0):

For example the block "analogous threshold trigger" with following block parameters is suitable for that...

a) Ax = n, that is the digital output Q of the threshold value countercounter is supposed to be withwith appropriate relation "= ON". Set block parameters as follows: GAIN = 1,0; OFFSET = 0; Threshold values: ON = n; OFF = n + 1
Example n = 0: ON = 0; OFF = 1; then ON Q = is if Ax = 0 is.

B) Ax > n, that is the digital output Q of the threshold value countercounter is supposed to be withwith appropriate relation "= ON". Set block parameters as follows: GAIN = 1,0; OFFSET = 0; Threshold values: ON = OFF = n
Example n = 0: ON = 0; OFF = 0; then ON Q = is, when Ax is > 0.
This is therefore the test onto positive numbers Ax.

C) Ax < n, that is the digital output Q of the threshold value countercounter is supposed to be withwith appropriate relation "= ON". Set block parameters as follows: GAIN = -1,0; OFFSET = 0; Threshold values: ON = OFF = -n
Example n = 0: GAIN = -1,0; ON = 0; OFF = 0; then ON Q = is, when Ax is < 0.
This is therefore the test onto negative numbers Ax.

D) Ax >= n, that is the digital output Q of the threshold value countercounter is supposed to be withwith appropriate relation "= ON". Set block parameters as follows: GAIN = 1,0; OFFSET = 0; Threshold values: ON = n; OFF = n - 1
Example n = 2: ON = 2; OFF = 3; then ON Q = is if Ax >= 2 is.

E) Ax =< n, that is the digital output Q of the threshold value countercounter is supposed to be withwith appropriate relation "= ON". Set block parameters as follows: GAIN = -1,0; OFFSET = 0; Threshold values: ON = -n; OFF = -n - 1
Example n = 2: GAIN = -1,0; ON = -2; OFF = -3; then ON Q = is if Ax =< 2 is.

In the same way "Analog threshold trigger" can be checked with the block, whether an analog value within aconstant k of "ON" = k1 - 1 to k2 = "OFF" (with "ON" < "OFF") to contain is Ax inside this fild or not (to use inverted block output for that), "ON", to have to lie "OFF" in the range of -20000 to 20000. At values n, k1, k2 outside of the this range must be used however for the comparison a block "comparator" (or two), in analog mode to the comparison of two analog values...

A comparison of two analog values with each other is under following link described:

With LOGO! how can you compare 2 analog values with each other?

I enlarged this basic circuit for the general applicationapplication and put explanations about suitable parameters on this basic circuit. Have a look at the circuitcircuit "DEMO_Groessenvergleich_von_zwei_Analogwerten.lsc" for this purpose in the file attachment.

Best regards
Betel