0 to 20mA Analog Scaling Calculator

0 to 20mA Calculator For DCS / PLC Programmer and E&I Engineer

0-20mA signals are widely used  in  various field Instruments

0 to 20mA  is being used as a  current representation for field Instrumentation measurement range.

( 0 to 20mA )  Signal from the Instruments, will be  send to an analog Card  reside in a PLC / DCS Controller.

In the PLC/ DCS Controller, the Current signal will be converted back to its Actual Instrument value  by multiplying it with a scale Constant .

The User then will be able to view the actual value of the field instruments  from his / her HMI or SCADA Interface.

Who need to Know how to Scale the Analog Factor 

1. PLC Programmer
2. DCS Engineer
3. E & I Engineer

Common Raw Value Setting From Well Known PLC / DCS  Vendor

How  to Convert 0 to 20mA  ? 

Example Scenario

(1)   E&I engineer went  on site to measure  the  Analogue Output Current  of a Temperature Transmitter . The Value  recorded  was  10mA.

(2)  He then  check the Temperature Transmitter Specification Sheet . The Minimum Range is 0°C , while the Maximum range is 200°C

(3)He  got the Measured Current , and  want to know what is the Calculated Temperature  ?

The Findings  as below

Signal Range in Voltage :  0 to 20mA

Instrument Range : 0°C to 200°C

Measured Current Value :   10mA

Instruments Current Value :      ??°C   ( This is what he wanna Find Out )

Step 1

Determine the Range of the Field instrument

Range  = High Limit – Low Limit

Range =  200°C – 0 °C

Step 2

Analog Range  = 20-0

Step 3

Calculate Temperature Value base on field measured voltage

Instrument Temperature = 200 x [ 10/20 ]

= 100°C

Check Out 0 to 10V Analog Conversion Calculator