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Old May 25th, 2018, 04:33 AM   #1
IdealDan
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Function block for analog scaling in mitsubishi gx works3

Hi Friends,
Please, who can tell me the Function Block used for scaling 4-20mA to say 0-200PSI in Mitsubishi GX Works3?
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Old May 25th, 2018, 08:37 AM   #2
BryanG
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I know nothing of GX Works3, but in general built in functions aren't always needed, write your own scaling function:


Code:
// Scaling uses this formula:
// Ov = [(Osh  Osl) * (Iv - Isl) / (Ish  Isl)] + Osl
// 
// Ov = scaled output value
// Iv = analog #Input value
// Osh = high limit OF the scale FOR the scaled #Output value
// Osl = low limit OF the scale FOR the scaled #Output value
// Ish = high limit OF the scale FOR the analog #Input value
// Isl = low limit OF the scale FOR the analog #Input value
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Old May 25th, 2018, 08:50 AM   #3
IdealDan
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Quote:
Originally Posted by BryanG View Post
I know nothing of GX Works3, but in general built in functions aren't always needed, write your own scaling function:


Code:
// Scaling uses this formula:
// Ov = [(Osh  Osl) * (Iv - Isl) / (Ish  Isl)] + Osl
// 
// Ov = scaled output value
// Iv = analog #Input value
// Osh = high limit OF the scale FOR the scaled #Output value
// Osl = low limit OF the scale FOR the scaled #Output value
// Ish = high limit OF the scale FOR the analog #Input value
// Isl = low limit OF the scale FOR the analog #Input value
Ok Bro. Thanks for the response.


Assuming a 4-20mA to 0-200PSI Scaling, From above: Do you mean

Osh = high limit OF the scale FOR the scaled #Output value=200psi ?

// Osl = low limit OF the scale FOR the scaled #Output value=0psi ?

// Ish = high limit OF the scale FOR the analog #Input value=20mA ?

// Isl = low limit OF the scale FOR the analog #Input value= 4mA ?


// Iv = analog #Input value (SHOULD THIS BE THE TAG)?

Last edited by IdealDan; May 25th, 2018 at 08:55 AM.
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Old May 25th, 2018, 09:56 AM   #4
BryanG
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If the Input Value is in mA, then yes.


On the PLCs I use the Input Value is the output of the Analog block and in the range of 0 to 27648. So for me Osh and Osl would be 200.0 and 0.0, Ish and Isl would be 27648.0 and 0.0. You will need to be working Floating Point numbers.
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Old May 25th, 2018, 10:19 AM   #5
IdealDan
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Quote:
Originally Posted by BryanG View Post
If the Input Value is in mA, then yes.


On the PLCs I use the Input Value is the output of the Analog block and in the range of 0 to 27648. So for me Osh and Osl would be 200.0 and 0.0, Ish and Isl would be 27648.0 and 0.0. You will need to be working Floating Point numbers.
You are right. Resolution 0-27648 for siemens, 0-16383 for AB SLC.
I need to figure out Mitsubishi's Resolution,
I Trust some one here will have an idea
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Old May 25th, 2018, 01:39 PM   #6
tarik1978
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It depends upon your IN/OUT analog module reference check this link:
https://us.mitsubishielectric.com/fa...alog-io-module
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Old May 26th, 2018, 12:40 PM   #7
BryanG
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The 0 to 27648 I gave would be for a 0-20mA signal, 4-20mA would be 5529 to 27648. 5529, is 27648 divided by 20 multiplied by 4.
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