EXtended high and low limit calculator

What is Lower Range Value (LRV) of a transmitter?

Lower range value is the smallest measurement that a device can calibrated to measure. Another name for the LRV is Zero.

What is Upper Range Value (URV) of a transmitter?

Upper range value is the maximum measurement that a device can be calibrated to measure. Another name for the URV is Span.

What is extended lower limit value of a transmitter?

In the event that the process variable falls below the instrument calibration range, the extended low range is employed to measure the process variable’s lower value.

What is extended higher limit value of a transmitter?

In the event that the process variable rises above the instrument calibration range, the extended high range is employed to measure the higher value of the process variable.

Formula for calculating EHL and ELL value

ELL value = LRV-((URV-LRV)*ELL LIMIT %)

EHL value = ((URV-LRV)* EHL LIMIT %)+URV

Example calculation:

For instance, the level of a tank with a range of -200 to 800 inch  is the process variable to be monitored with Extended Low Limit (ELL) is set to 5% Extended High Limit (EHL) is set at 3%.

ELL value calculation

The Range is then 100 and the LRV is -200 inch

URV is 800 inch

ELL value = LRV-((URV-LRV)*URV LIMIT%)

ELL value =-200-((800-(-200))*(5/100))

ELL value =-200-(1000*0.05)

ELL value = – 250 inch

The Extended Low limit value can be -250 inch if the Extended Low Limit (ELL) is set to 5%. 

EHL value calculation

EHL value = ((URV-LRV)* EHL LIMIT%)+URV

EHL value = ((800-(-200))*(3/100))+800

EHL value =  (1000*0.03)+800

EHL value = 830 inch

The Extended high limit value  can reach 830 inch if the Extended High Limit (EHL) is set at 3%.

Extended high and low limit calculator

The below calculator used to calculate the Extended high and low limit of the process variable 

Click here for more Instrumentation Calculators