i'm tring to set maximum and minimum value like showed in the picture.
http://postimg.org/image/88qekr6jn/
it seems that nothing change if I change the value of constants, is it the right way to set the range of device?
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Yes, you can set the range of AI channel in this way.
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From the LabVIEW help for Input Limits:
Input limits are the maximum and minimum values you expect to measure, after any scaling, including custom scaling. Input limits are sometimes confused with device range. Device range refers only to the input range of a particular device. For instance, the device range for a DAQ device might be 0 to 10 V, but that device might be used with a temperature sensor that outputs 100 mV for every 1 °C. The input limits in that case could be 0 to 100, with 10 V corresponding to 100 °C.
Input limits in a smaller range can improve the precision of your measurement. If, in the previous example, you knew that the temperature would never be higher than 50 °C, you could choose a minimum value of 0 and a maximum value of 50. The device can then detect smaller differences in temperature because it is digitizing a voltage between 0 and 5 V, rather than 0 and 10 V.
Whether a change in input limits will result in an actual change in device range depends on what DAQ device you are using. For example the low-end USB-600x series devices only have a +/- 10 V range. You don't say what effect you are expecting to see when you change the input limits but it may be that your change is having no effect because there is no change in the device's range.
