Model 4101-28/5100-28 IR Gas Sensor Module (7/03)
Page:
Instruction Manual
3
START DELAY:
power up delay in progress
SWITCH ON:
magnetic reed switch is
activated
SENSOR FAULT:
fault present, sensor or
sensor wiring table
SETTING ZERO:
calibration zero gas setting
in progress
APPLY 50%:
apply 50% of span
calibration gas
SETTING SPAN:
span gas detected,
automatic span setting in
progress
GAS:
remove calibration gas
FAIL CAL:
calibration span setting
failed
TIME-OUT:
calibration failed, no gas
detected in calibration
SENSOR FAIL:
sensor or sensor
connections failed
NEG DRIFT:
excessive negative sensor
drift
Table 2: Messages
2.2.4 Sensor Life
Sensor life of the module can be expected to exceed 5
years.
Sensor response may deteriorate very slowly over a pe-
riod of years, depending on exposure to environmental
factors. If calibration becomes impossible for any rea-
son, the analog output will lock at 2.5mA and the status
LED flashes red. Install a new 4101-28 module and re-
calibrate. The calibration function automatically adjusts
span amplifier gain across a broad range without any
need for manual adjustment of potentiometers or jump-
ers.
2.2.5
Test Jacks
The module is equipped with test jacks to facilitate con-
venient current loop measurements without opening the
external current loop. To make measurements use the
following procedure;
1. Attach the current meter leads to the test jacks lo-
cated on the face plate.
2. Apply test gas and take meter readings. Set external
controller to Bypass if necessary to avoid unwanted
alarm response.
3. Remove meter leads from test jacks.
CURRENT
OUPUT
LED RED
LED GREEN
(mA)
STATUS
STATUS
Start-up delay
3
Slow Flash
Start Delay
Excess drift (>10%)
2.5
Blip/blink
NEG DRIFT
Auto Zero set
3
Solid
SETTING ZERO
Apply calibration
gas
3.3
Fast Flash
Apply 50% LEL
Span is set, remove
gas
3.6
Solid
REMOVE GAS
Return to normal
operation
3.6
Solid
CAL COMPLETE
Normal
4
Blip/blink
0.00%
Gas Present
4.4 – 20.0
Blip/Blink
1.0% TO 99% LEL
CONDITION
ALPHANUMERIC
Table 3: LED Status
Note:
The 4101-28's to 20 mA current output must be con-
nected to a load device in order to facilitate the use of the
test jacks (ie. 100 Ohm resistor must be connected between
the 4 to 20 mA signal output and the common terminal if the
unit is being bench tested to field installation).
