Det-Tronics UD10 DCU Emulator FlexVu Universal Display Unit - Manual (Page 68)

4.2 95-8656 N-1
AppenDix n
UD10-DCU with gENERIC 4-20 ma SENSORS
noTe
For complete information regarding installation, wiring, and calibration of the sensor, refer to the instruction
manual provided by the sensor manufacturer.
operAtion
The UD10-DCU can be used with generic sensors
that generate a calibrated linear 4-20 mA signal, with
or without HART. The UD10-DCU allows the operator
to select the upper and lower range values and unit
of measurement. The UD10-DCU then analyzes the
4-20 mA input signal from the sensor and displays the
value with the designated measurement unit, and also
controls the alarm outputs.
UPPER aND LOwER RaNgE vaLUES
The upper range value (URV) and lower range value
(LRV) are selected using the magnetic tool and the
UD10-DCU’s menu system (Main Menu > Device
Setup). The URV corresponds to the 20 mA signal while
the LRV corresponds to 4 mA. The default values are
0 for the LRV and 100 for the URV. When the generic
detector supports HART communication, the URV and
LRV come from the attached detector.
mEaSUREmENT UNIT TExT
The operator can select the appropriate measurement
unit from a pre-entered list: % (default), PPM, LFL, or
PPB, or he can enter his own custom 4-character string.
Measurement unit text is displayed on the main screen
with the process variable. When the generic detector
supports HART communication, the unit text comes
from the attached detector.
LOw FaULT ThREShOLD
The operator can enter a low input fault threshold in the
range of 0.5 to 4 mA (default is 3.5 mA). When the input
signal is at or below this point, an “Out of Range Low
Fault” is annunciated. This feature can be enabled/
disabled as desired.
hIgh FaULT ThREShOLD
The operator can enter a high input fault threshold in the
range of 20 to 27 mA (default is 21 mA). When the input
signal is at or above this point, an “Out of Range High
Fault” is annunciated. This feature can be enabled/
disabled as desired.
aLaRmS
The Low, High and Auxiliary alarm levels are
independently field adjustable. Alarm levels are set
and displayed with the selected measurement units. All
alarm levels must be within the LRV to URV range.
aLaRm LaTChINg
Latching or non-latching function is independently
selectable for each alarm. The default setting is
non-latching. Latched alarms can be reset with a “Reset
Latched Alarms” command from the menu system or a
power cycle.
SENSOR CaLIbRaTION
The UD10-DCU does not support generic sensor
calibration. Generic sensors must be pre-calibrated
following the procedure described in the instruction
manual provided by the sensor manufacturer.
4-20 ma OUTPUT REaDINg
While in Generic mode, the UD10-DCU displays values
below the 4 mA level to allow the use of 0-20 mA
sensors.
menu structure
UD10-DCU with generic 4-20 ma Sensors
Refer to the following menus when using the
UD10-DCU’s LCD display and internal magnetic
switches. Two different menus are provided to
accommodate sensors with or without HART
communication.
menu HeLp
Status menus only allow the user to view the data.
The Setup menus allow the user to both view and
edit the data.