1
Technical Note
00840-1400-4801, Rev BB
Rosemount DP Level
April 2019
Rosemount DP Level
Rising to new levels with Rosemount 3051S
Electronic Remote Sensor (ERS) Systems and
Tuned-System Assemblies
1.0 Executive summary
Differential Pressure (DP) technology has been used for many years to measure tank level. Internal tank
architecture, agitation, corrosive or viscous processes that may cause challenges for alternative level
technologies are ideal applications for DP level technology, which delivers a repeatable, stable and
accurate measurement when utilized correctly.
Traditional DP technologies, such as wet leg and dry leg systems, which utilize impulse piping as well as
capillary based solutions, are well understood and reliable technologies. Impulse lines benefit from clean
processes as they are prone to plugging and may freeze in extreme cold ambient temperatures. Capillary
solutions continue to give excellent measurements when capillary lengths can be minimized. However,
these traditional DP level systems can be difficult to use in areas and applications with wide ambient and
process temperature shifts.
Improvements to traditional measurement technology, such as Tuned-System
™
Assemblies, have been
developed to increase response time and reduce measurement error and are considered best practices
for indoor applications and shorter spans and tanks with high pressure vessels.
Another DP level instrumentation innovation is the Rosemount
™
3051S Electronic Remote Sensor (ERS)
™
System. This technology builds upon the proven DP technology and is suited to distillation towers, tall
vessels and other applications with long spans or widely varying temperature. The Rosemount 3051S
ERS System (Figure 1) replaces mechanical impulse piping and long lengths of capillary with two
pressure transmitters that are linked together electronically. Differential pressure is calculated in one of
the two sensors and is transmitted to the DCS or PLC using a standard two-wire 4–20 mA HART
®
signal.
Figure 1. Rosemount 3051S ERS System
With a Rosemount 3051S ERS System, a digital signal replaces impulse lines and capillary to increase measurement
reliability and performance on tall towers and vessels.