Det-Tronics UD20 FlexVu Explosion-Proof Universal Display Unit - Manual (Page 4)

3.1 95-8620 2
HART COmmUNICATION
The UD20 is a HART primary master and communicates
with the GT3000, which is a HART slave device.
Upon power-up, the UD20 requests the gas type,
measurement range, and unit of measure from the
GT3000. During normal operation, the UD20 continually
polls the GT3000 for status information. Because the
UD20 is a primary master, a secondary master can also
be used to communicate with the GT3000 at the same
time. If an Asset Management System (AMS) is used,
it should be configured as a secondary master to avoid
communication conflicts with the UD20.
mAgNETIC SwITCHES
Four internal magnetic switches provide a non-intrusive
user interface that allows adjustment of configuration
parameters and calibration in the field without the use
of a HART handheld device.
The switches are labeled as follows:
Cancel, Escape
Enter, Select
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DEvICE ENClOSURE
The housing for the UD20 consists of a multi-port
aluminum or stainless steel explosion-proof junction
box with a clear viewing window. Available conduit
entry sizes include 3/4 inch NPT and M25.
DEvICE DISplAy
The UD20 is provided with a 160 x 100 dot matrix LCD
display. See Figure 1.
During normal operation, the UD20’s LCD display
indicates the gas type and units measured.
The UD20 communicates with the sensor and allows
easy access to the following information:
• Sensor (GTS) information/fault/status
• Transmitter (GTX) information/fault/status
Refer to Appendix A for details regarding the HART
menu structure.
lOggINg
The UD20 has no logging capability of its own, but
reads the logs that are stored in the GT3000 and
displays them on the LCD screen. If an AMS is used,
it communicates directly with the GT3000 and not with
the UD20.
GT3000
GAS
DETECTOR
UD20
CONTROL
SYSTEM
Operating and history logs that are stored in the GT3000
and displayed by the UD20 include:
• Calibration
• Sensor running hours
• Sensor temperature
• Events
OUTpUT TEST
The UD20 can start and stop a 4-20 mA Loop Test for
checking correct operation of system output devices.
REAl TImE ClOCk
The Real Time Clock resides in the GT3000 and can be
set by the UD20, HART handheld, or AMS. The UD20
reads and displays the current time/date from the GT3000.
CANCEL / ESCAPE
ENTER / SELECT
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NEXT
B2426
Figure 1—Faceplate of UD20