Current Control; Current Limit; Reverse Polarity Protection - Emerson Rosemount 2151N Reference Manual

Rosemount 2151N

CURRENT CONTROL

CURRENT LIMIT

REVERSE POLARITY
PROTECTION
45
The current control amplifier consists of two operational
amplifiers, two transistors, and associated components. The
first amplifier provides an adjustable gain output proportional
to the sum of the differential sensor current and a zero
adjustment current. This output is supplied to the second
amplifier, which controls the current in the 4-20 mA loop
proportionally.
The current limiter prevents output current from exceeding 30
mA nominal in an overpressure condition. Conversely,
minimum output is limited to 3 mA nominal. Both the minimum
and maximum current limits may vary slightly depending upon
sensor pressure range code and associated calibration.
A diode provides reverse polarity protection.
Reference Manual
00809-0000-4851 Rev AD
December 2023
Operation