1
MODEL 54eA SECTION 1.0
SPECIFICATIONS
SECTION 1.0SPECIFICATIONS1.1 FEATURES AND APPLICATIONS
The Model 54eAAnalyzer/Controller with the appro-
priate sensor monitors and controls dissolved oxy-
gen (ppm and ppb level), free chlorine, total
chlorine, and ozone in a variety of process liquids.
The analyzer is compatible with Rosemount
Analytical series 499A amperometric sensors for
oxygen, chlorine, and ozone; and with Hx438 and
Gx448 steam sterilizable oxygen sensors.
The amperometric sensors used with the Modeal
54eA produce a current directly proportional to the
concentration of the substance being determined.
Sensor currents are in the microampere to nanoam-
pere range.
For oxygen measurements, an on-board pressure
sensor allows truly automatic air calibration. Simply
expose the sensor to water-saturated air. Wait until
readings are stable and press a button. The analyz-
er measures temperature and barometric pressure
and automatically completes the calibration.
For free chlorine measurements, both automatic and
manual pH correction are available. pH correction is
necessary because amperometric chlorine sensors
respond only to hypochlorous acid. To measure free
chlorine (hypochlorous acid plus hypochlorite ion)
most competing analyzers require an acidified sam-
ple. Acid lowers the pH and converts hypochlorite
ion to hypochlorous acid. The 54eA analyzer elimi-
nates the need for messy and expensive reagents
by using the sample pH to correct the chlorine sen-
sor signal. If the pH is relatively constant, a fixed pH
correction can be used. If the pH is greater than 7
and fluctuates more than about 0.2 units, continuous
measurement of pH and automatic pH correction is
necessary. Corrections are valid to pH 9.5.
The 54eA analyzer fully compensates oxygen,
ozone, free chlorine, and total chlorine readings for
changes in membrane permeability caused by tem-
perature changes.
For pH measurements — pH is available with free
chlorine only — the 54eA features automatic buffer
recognition with stabilization check. Buffer pH and
temperature data for commonly used buffers are
stored in the analyzer. Glass impedance diagnostics
warn the user of an aging or failed pH sensor.
The analyzer has a rugged, weatherproof, corrosion-
resistant enclosure (NEMA4X and IP65) of epoxy-
painted aluminum. It is suitable for panel, pipe, or wall
mounting. Ahinged front cover provides convenient
access to wiring. Programming and calibration are
through the front membrane keypad, which has tac-
tile feedback. The large back-lit dot-matrix display
shows the main measurement (oxygen, chlorine, or
ozone) in large numerals. The temperature and out-
put current are shown in smaller numerals on the
second line. Two user-selectable variables can be
displayed on the third line. The pH measurement, if
used, appears on the third line.
Two independent, galvanically isolated outputs provide
4-20 mA or 0-20 mAsignals for oxygen, chlorine,
ozone, pH, or temperature. Output 1 includes a HART
digital signal superimposed on the analog signal. The
controller option allows PID control on any measure-
ment.
The Model 54eA has three programmable alarm
relays. Alarms can be assigned to the amperometric
measurement, pH, or temperature. Alarms have pro-
grammable high or low activation, independent set-
points, adjustable deadband, and time delay. Any
relay can be configured as a timer to control a spray
cleaner for the dissolved oxygen sensor. An over-
feed timer feature is also available. The controller
option allows each alarm to be configured for time
proportional control (TPC). Afourth relay is a dedi-
cated fault alarm.
The Model 54eA analyzer is a member of the
Rosemount SMART FAMILY®of instruments. The
analyzer communicates with the Model 275 HART®
communicator or any other host, including AMS, that
supports the 275 HART communication protocol.
® SMARTFAMILY is a registered trademark of Rosemount Inc.
® HARTis a registered trademark of the HART Communication Foundation.