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GENERAL SPECIFICATIONS FOR Xmt-A
Input ranges: 0-330 nA, 0.3-4µA, 3.7-30 µA,
27-100 µA
Repeatability (input): ±0.1% of range
Linearity (input): ±0.3% of range
Temperature range: -10 to 100°C (-10 to 150°C for
steam sterilizable sensors)
Temperature accuracy using RTD: ±0.5°C between
0 and 50°C, ±1°C above 50°C
Temperature accuracy using 22k NTC: ±0.5°C
between 0 and 50°C, ±2°C above 50°C
Digital Communications:
HART: PV, SV, TV, and 4V assignable to measure-
ment (oxygen, ozone, chlorine, or monochlo-
ramine), temperature, pH, and sensor current.
Fieldbus: Four (4) AI blocks assignable to meas-
urement (oxygen, ozone, or chlorine), tempera-
ture, pH, and sensor current; execution time 75
msec. One PID block; execution time 150 msec.
Device type: 4086. Device revision: 1. Certified to
ITK 4.6.
HAZARDOUS LOCATION APPROVALS
Intrinsic Safety (with appropriate safety barrier):
Class I, II, III, Div. 1
Groups A-G
T4 Tamb = 50°C
Class I, II, III, Div. 1
Groups A-G
T4 Tamb = 50°C
1180 II 1 G
Baseefa04ATEX0213X
EEx ia IIC T4
Tamb = 0°C to 50°C
Non-Incendive:
Class I, Div. 2, Groups A-D
Dust Ignition Proof
Class II & III, Div. 1, Groups E-G
NEMA 4/4X Enclosure
Class I, Div. 2, Groups A-D
Dust Ignition Proof
Class II & III, Div. 1, Groups E-G
NEMA 4/4X Enclosure
T4 Tamb = 50°C
MODEL Xmt-A AMPEROMETRIC TRANSMITTER
FEATURES
The Model Xmt-A Transmitter with the appropriate
sensor measures dissolved oxygen (ppm and ppb
level), free chlorine, total chlorine, monochloramine,
and ozone in water and aqueous solutions. The trans-
mitter is compatible with Rosemount Analytical 499A
amperometric sensors for oxygen, chlorine, monochlo-
ramine, and ozone; and with Hx438, Bx438, and
Gx448 steam-sterilizable oxygen sensors.
For free chlorine measurements, both automatic and
manual pH correction are available. pH correction is
necessary because amperometric free chlorine sen-
sors respond only to hypochlorous acid, not free chlo-
rine, which is the sum of hypochlorous acid and
hypochlorite ion. To measure free chlorine, most com-
peting instruments require an acidified sample. Acid
lowers the pH and converts hypochlorite ion to
hypochlorous acid. The Model Xmt-A eliminates the
need for messy and expensive sample conditioning by
measuring the sample pH and using it to correct the
chlorine sensor signal. If the pH is relatively constant,
a fixed pH correction can be used, and the pH meas-
urement is not necessary. If the pH is greater than 7.0
and fluctuates more than about 0.2 units, continuous
measurement of pH and automatic pH correction is
necessary. See Specifications section for recommend-
ed pH sensors. Corrections are valid to pH 9.5.
The transmitter fully compensates oxygen, ozone, free
chlorine, total chlorine, and monochloramine readings
for changes in membrane permeability caused by tem-
perature changes.
For pH measurements — pH is available with free
chlorine only — the Xmt-A features automatic buffer
recognition and stabilization check. Buffer pH and
temperature data for commonly used buffers are
stored in the transmitter. Glass impedance diagnostics
warn the user of an aging or failed pH sensor.
ATEX
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