Find milliamps from the known process variable
A simple method to find milliamps(mA) from the given process variable(PV) and vice versa.
Formula
![\[mA=\left ( \frac{PV-LRV}{SPAN} \right )16+4\]](https://instrumentationbasic.com/wp-content/ql-cache/quicklatex.com-ed13c604a64d8742300b4526ce56b512_l3.png "Rendered by QuickLaTeX.com")
SPAN=URV-LRV
Consider a transmitter is reading 45kg/cm2.And the range of the transmitter is 0 to 100kg/cm2.how to find the mA for the process variable.
PV = 45 LRV =0 URV=100 SPAN=100
![\[mA=\left ( \frac{45-0}{100} \right )16+4\]\[mA=\left ( \frac{45}{100} \right )16+4\]\[mA=\left ( 0.45 \right )16+4\]\[mA=7.2+4\]\[mA=11.2\]](https://instrumentationbasic.com/wp-content/ql-cache/quicklatex.com-23c441207d7e9622497f0808e13dfcba_l3.png "Rendered by QuickLaTeX.com")
For Example, if the output of the transmitter is 16.2mA. And the range of the transmitter is 0 to 100kg/cm2.how to find the PV for the output mA.
mA = 16.2 LRV =0 URV=100 SPAN=100
![\[16.2=\left ( \frac{PV-0}{100} \right )16+4\]\[16.2-4=\left ( \frac{PV}{100} \right )16\]\[12.2=\left ( \frac{PV}{100} \right )16\]\[\frac{12.2}{16}=\left ( \frac{PV}{100} \right )\]\[PV=\frac{12.2}{16}*100\]\[PV=76.25\]](https://instrumentationbasic.com/wp-content/ql-cache/quicklatex.com-c5c76d5172b13a183845a51fe6275f72_l3.png "Rendered by QuickLaTeX.com")
