Det-Tronics PIRECL Infrared Hydrocarbon Gas Detector PointWatch Eclipse - Manual (Page 20)

18 95-8526 14.2
opERation
faCtory DefaUlt SettingS
The Pointwatch Eclipse is shipped from the factory pre-
calibrated and set for the customer’s choice of 0-100%
LFL methane, propane, ethylene, or butane. Detection
of gases other than the factory default gas will require
changing the gas setting and performing field calibration
of the device. HART or MODBUS communication is
required to change the factory default settings. Refer
to the HART Communications Appendix within this
document for additional guidance.
operating MoDeS
The Eclipse has three operating modes: warm-up,
normal, and calibrate.
warm-up
Warm-up mode is entered upon application of 24 Vdc
operating power. During warm-up, the 4-20 mA current
loop output will indicate warm-up, the indicating LED is
yellow, and the alarm outputs are disabled. The warm-up
mode lasts nominally two (2) minutes after power-up.
normal
After warm-up mode is completed, the device
automatically enters the Normal mode, and all analog
and alarm outputs are enabled.
Calibrate
Calibration of the Eclipse is normally not required; however,
the user has the option to verify proper calibration or to
perform calibration procedures if necessary. Guidelines
for when to perform a calibration or a response test are
listed in Table 2. The user has the choice of three methods
to place the device into the Calibrate mode. Refer to the
"Calibration" section in this manual for details.
4-20 Ma CUrrent loop oUtpUt
Eclipse provides an isolated, linear current loop output
that is proportional to the detected gas level. Fault and
calibration status are also indicated by this output.
The factory default for full-scale 100% LFL output is 20
mA. Other full scale values (from 20 to 100% LFL) can
be selected using HART or MODBUS communication.
HART and MODBUS interfaces also have the ability to
calibrate the 4 mA and 20 mA levels.
When the default setting is selected, the LFL percentage
for a given current reading can be calculated using the
formula:
% LFL = (X – 4) ÷ 0.16
X = Current reading
in milliamperes
Example: Device reads 12 mA.
12 – 4 = 8
8 ÷ 0.16 = 50
50% LFL is indicated.
Normally, the current loop output is proportional to the
selected standard gas type only.
table 2—Calibration or Response test
function Calibration response
test
Startup X
Gas selection changed X
Non-standard gas
(using linearization other than methane) X
Replace any part X
Constant zero offset X
Periodic Functional Testing
(at least once a year) X