4.1 95-862011
3. When the zero calibration is complete, the yellow
LED changes from steady to blinking and the UD20
indicates “Waiting for Gas.” Apply the calibration
gas to the sensor. When gas is detected, the UD20
indicates “Waiting for Span.”
4. When the yellow LED turns off and the UD20
indicates “Remove Cal Gas”, remove the calibration
gas. The gas level at the sensor gradually returns to
zero. The green LED turns on steady to indicate that
the device has returned to normal operation, using
the new calibration data.
INPUT TRIM
The input current loop of the UD20 is trimmed at the
factory. However, it can also be trimmed in the field
using the following automated process.
Navigate through the menu to “Input Loop Cal.”
Main Menu
Process Vars
Display Status
Device Status
Display Setup
Device Setup
Device Cal
Device Test
Display Setup
Contrast Control
Input Loop Cal
Upon entering Input Loop Cal, the UD20 commands
the detector to output 4 mA, and then automatically
calibrates its own input. The UD20 then commands the
detector to output 20 mA, and subsequently calibrates
its own input.
specificAtions
UD20 UNIVERSAL DISPLAY UNIT
OPERATING VOLTAGE—
24 Vdc nominal, operating range is 19 to 30 Vdc.
UD20 maximum loop voltage drop (Vd) 5.0 volts.
Maximum loop supply 30.0 Vdc.
OPERATING POWER—
0.8 watt maximum.
OPERATING CURRENT—
A minimum of 3.5 mA.
CURRENT OUTPUT—
Linear 4-20 mA
(with HART output directly from detector).
250 ohm, 3 watt termination resistor required (included).
OPERATING TEMPER ATURE—
–20°C to +70°C.
STORAGE TEMPERATURE—
–40°C to +70°C.
HUMIDITY RANGE—
5 to 95% RH (Det-Tronics verified).
SENSOR COMPATIBILITY—
The UD20 can be used with any of the Det-Tronics
GT3000 line of gas detectors, or the Det-Tronics Model
PIRECL hydrocarbon gas detector.
WIRING TERMINALS—
Terminals can handle wire sized from 22 to 14 AWG.
CONDUIT ENTRIES—
3/4” NPT or M25.
(Five conduit entries standard.)
ENCLOSURE MATERIAL—
Epoxy coated aluminum or 316 stainless steel.
SHIPPING WEIGHT—
Aluminum: 4.15 pounds (1.88 kilograms).
Stainless steel: 10.5 pounds (4.76 kilograms).
DIMENSIONS—
See Figures 12 and 13.
ELECTRO-MAGNETIC COMPATIBILITY—
EMC Directive 2004/108/EC
EN55011 (Emissions)
EN50270 (Immunity)
WARRANTY—
12 months from date of installation or 18 months from
date of shipment, whichever occurs first.
Table 4— PIRECL LEDs and 4-20 mA Output
During Various Status Conditions
Function
Green
LED
Yellow
LED
Analog
4-20 mA
Signal
Warm-up Off Steady On 3.0
Normal
Operation
Steady On Off 4-20
Fault
Condition
Off Steady On 3.0
Blocked
Optics
Off Steady On 3.0
Calibration See Table 2 3.8
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