adccommunitymod (AutomationDirect) asked a question.

Conversion to PSI

Created Date: September 22,2008

Created By: rromanelli

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I am using a analog input F4-16AD to receive a value from a sensor. My sensor is a 4-20mA and the range is -1 to 40 kg. I need to obtain the signal in V4005, but in PSI . I am using the formula tha exists in manual but the value is not correct What I need to do to convert the value to sensor to Vmemory ?


  • adccommunitymod (AutomationDirect)

    Created Date: September 22,2008

    Created by: KPrice

    rromanelli, I need to know the units for your sensor range, but for example I will assume your sensor range is: 4-20mA for -1 kg/cm2 to 40 kg/cm2. I have a conversion factor of 14.22 psi per kg/cm2. So after conversion, your range in psi is: 4-20mA for -14.22 psi to 568.8 psi. This gives a full-scale span of: 583 psi for the 0 to 4095 raw data. Do you agree with all of this so far? If your sensor range is in other units, then this would be incorrect. (I must be assuming the wrong units because this range seems strange to me.)

    Your offset or "zero " is -14.22 psi. How do you want to handle the negative value, an BCD with a sign relay? real number? BCD with an offset? There have been other posts that pointed out the advantages and disadvantages to each method.

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  • adccommunitymod (AutomationDirect)

    Created Date: September 22,2008

    Created by: rromanelli

    Conversion to PSI

    Yes, this is the sensor range !!!

    In my program I used the instruction according the manual to convert the value :

    -LDF X20

    K12

    -BCD

    -LDF X34

    K4

    -OUTX V4000

    After this I used this : D= (H-L)/4095 ; (568-(-14,2))/4095

    LD V4000

    MUL K582

    DIV 4095

    OUT V5000

    Is this correct ? I am using V5000 to view the value in PSI

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  • adccommunitymod (AutomationDirect)

    Created Date: September 22,2008

    Created by: rromanelli

    I am using a analog input F4-16AD to receive a value from a sensor. My sensor is a 4-20mA and the range is -1 to 40 kg.

    I need to obtain the signal in V4005, but in PSI .

    I am using the formula tha exists in manual but the value is not correct

    What I need to do to convert the value to sensor to Vmemory ?