4.1 95-86203
FAULT CONDITIONS WHEN USED WITH PIRECL
When the UD20 is connected to the PIRECL, it
automatically programs the PIRECL for “User Defined
Fault Mode” upon power-up and sets the following
default output levels:
Calibration = 3.8 mA
Warm-up, General Fault, Blocked Optics = 3.0 mA
This is done to ensure that the loop current stays high
enough to keep the UD20 powered. The UD20 is a loop
powered device and requires a minimum of 2.6 mA to
operate properly. Setting the fault level to a value other
than default is not recommended.
If the UD20 is unable to change the mode, an “ANALOG
CODE FLT” fault is annunciated.
Refer to the PIRECL instruction manual, number 95-
8526, for complete information regarding fault detection
and fault modes.
Zero Drift Condition
Zero Drift Faults are not specifically indicated by the
UD20. When the process variable drops between 3.9
and 3.1 mA, no fault is indicated by the UD20. When the
process variable reaches 3.0 mA, the UD20 will display
a FAULT. If a FAULT condition is indicated, the user can
interrogate UD20 and PIRECL fault conditions within
the UD20 menu. If no specific fault is indicated, use the
menu to determine the PIRECL process variable. If that
value is ≤3.9 mA, the PIRECL is experiencing zero drift
and should be re-calibrated.
importAnt sAfety notes
CaUtIon
The wiring procedures in this manual are intended
to ensure proper functioning of the device under
normal conditions. However, because of the
many variations in wiring codes and regulations,
total compliance to these ordinances cannot be
guaranteed. Be certain that all wiring complies
with the NEC as well as all local ordinances. If
in doubt, consult the authority having jurisdiction
before wiring the system. Installation must be
done by a properly trained person.
CaUtIon
This product has been tested and approved
for use in hazardous areas. However, it must
be properly installed and used only under the
conditions specied within this manual and
the specic approval certicates. Any device
modication, improper installation, or use in a
faulty or incomplete conguration will render
warranty and product certications invalid.
CaUtIon
The device contains no user serviceable
components. Service or repair should never be
attempted by the user. Device repair should be
performed only by the manufacturer or trained
service personnel.
LIabILItIes
The manufacturer’s warranty for this product is
void, and all liability for proper function of the
Display is irrevocably transferred to the owner or
operator in the event that the device is serviced or
repaired by personnel not employed or authorized
by Detector Electronics Corporation, or if the
device is used in a manner not conforming to its
intended use.
CaUtIon
Observe precautions for handling electrostatic
sensitive devices.
CaUtIon
Unused entries must be closed with suitably
certied blanking elements upon installation.
instAll Ation
NOTE
The UD20 housing must be electrically connected
to earth ground. A dedicated earth ground
terminal is provided on the UD20.
Install gas detectors in the appropriate locations
following the guidelines below. The UD20 should be
located where it can be easily viewed by personnel. The
GT3000 can be attached directly to the UD20 housing,
or it can be mounted remotely using a Det-Tronics STB
termination box (see the “Sensor Separation” section
for additional information). The Model PIRECL should
be mounted as described in the PIRECL instruction
manual, number 95-8526. Detectors must always be
installed per local installation practices.
Always define the following application details:
IDENTIFICATION OF VAPOR(S) TO BE DETECTED
It is necessary to always identify the vapor(s) of interest
at the job site. In addition, the fire hazard properties
of the vapor, such as vapor density, flashpoint, and
vapor pressure should be identified and used to assist
in selecting the optimum detector mounting location
within the area.
