Specifications

65
FEATURES/BENEFITS
 New DRYCAP
®
sensor for accurate, reliable,
long-term stability and fast response
 Measures moisture content at process
temperatures up to 662 °F (350 °C)
 Excellent long-term stability
 User-programmable, versatile and easy to use
 Easy to install, calibrate, maintain
 NIST traceable (certificate supplied)
 Two analog outputs, serial interface
 Optional alarm relays and local display
The DMP 246 transmitter incorporates the new
DRYCAP
®
thin film polymer sensor. The DRYCAP
®
sensor is optimized to high temperature applications
and is accurate, reliable and stable for long periods.
Immune to particulate contamination, condensation
and most chemicals, the sensor can be used with
confidence in industrial environments. Even though
the polymer element has an upper operating limit of
below 392°F, a new probe design eliminates the
need for complicated sampling systems and allows
the sensor to be placed directly in temperatures up
to 662°F without sacrificing accuracy or stability.
This is accomplished without moving parts, addi-
tional power, or cooling utilities, therefore eliminat-
ing the risk of damaging the transmitter due to a
cooling failure.
The microprocessor-based transmitter measures
water vapor pressure, enabling it to output dewpoint
and mixing ratio. Relative humidity and temperature
measurements are used only during calibration and
when checking for the proper cooling effect.
THE COOLING SET
The DMP 246 comes with a cooling set as a standard
feature. The cooling effect may be regulated by
adding the cooling profiles, or removing them from
the set, to eliminate too effective cooling that could
increase the possibility of condensing water vapor.
Should there be any condensation, it only alters the
moisture reading until the water evaporates. The
DRYCAP
®
sensor is fully recoverable from a satu-
rated state.
The cooling rate is controlled by the process flow
rate and the delta temperature between the process
gas and surrounding ambient temperatures. If the
transmitter is operating close to the condensation
point and the operator is unsure of the process
conditions, the transmitter has a simple check
method for determining whether to install the
profiles or remove them.
OPTIONS AND ACCESSORIES
Display/Keypad Cover: The display/keypad option
displays the measurements at the point of installation.
It also makes the DMP 246 transmitter simple and
easy to use; the menus help the user to configure and
operate the transmitter.
Alarm Outputs: For applications where adjustable on/
off alarm control is needed, the alarm relay option is
the solution. Alarm relays include two SPCO (single
pole change over) type relays with up to
8 A/230 VAC contacts.
Cables: The probe cable of the DMP 246 can be
either two, five or ten meters long.
Power Unit: The DMP 246 has, in addition to the
standard 24 VAC/VDC, options for 115 VAC or 230
VAC operating voltages.
CALIBRATIONS MADE EASY
The transmitter software allows the user to perform
either one or two-point calibration, which ensures a
±2°C dewpoint accuracy in specified measurement
ranges. Calibrations are made against relative humid-
ity references (e.g. salt baths). The transmitter can
also be sent to Vaisala for a NIST traceable calibra-
tion. In typical conditions calibration once a year is
recommended.
DMP 246 Dewpoint Transmitter
For High Temperature Applications
DMP 246