User Manual

95-85321.4 14
Description
The Reset mode is entered by holding the Cal magnet to the side of the transmitter enclosure next to CAL/
RESET on the display face of the unit.
•Standard– WhentheCalmagnetisheldthereforless than one second, the alarm indicators turn off and
all relay outputs return to their normal condition if no alarms or faults are occurring.
•Forced– WhentheCalmagnetisheldtherefor 1 to 2 seconds, the alarm indicators turn off and the
relay outputs return to their normal condition even if an alarm or fault condition still exists.
•Remote– Activating the remote reset switch for less than 2 seconds initiates a forced reset.  If
“EXT CAL YES” was selected during the setup procedure, the external reset input initiates the
setpoint display cycle when activated for over two seconds.
When the Cal magnet is held to the side of the transmitter enclosure next to CAL/RESET for more than two
seconds, the transmitter enters the Setpoint Display mode. Once in this mode, the Cal magnet can be
removed. The Setpoint Display sequence will complete automatically. (The external reset input terminal can
also be used to initiate the setpoint display and calibration mode if “EXT CAL YES” was selected during the
setup procedure.) In this mode:
•The display sequentially shows the alarm setpoints, calibration gas concentration, as well as sensor
sensitivity and other information. Refer to “Table 5-Setpoint Display Cycle” for additional information.
•Eachvalueisdisplayedforapproximately1.5seconds.
•Aftercompletingthesequence,thetransmitterautomaticallyreturnstotheNormaloperatingmodeiftheCal
magnet is no longer being held to the unit (or the external reset input is not activated).
NOTE
If the CAL/RESET switch (or external reset input) is still activated at the end of this cycle,
the transmitter automatically enters the Calibrate mode. If a calibration is not performed,
a CAL ABORTED fault will occur. To exit the Calibrate mode without performing the
calibration, cycle power or wait for the calibration fault message, then reset the unit.
The Setpoint Display mode only displays the setpoints. Use the “Setup” mode for changing setpoints.
•AutoCalisanautomaticcalibrationprocedurethatrequiresnoadjustmentsbytheoperator.TheCalibrate
mode is entered by holding the Cal magnet to the CAL/RESET magnetic switch until completion of the
“Setpoint Display” sequence described above (approximately 7 seconds). (The external reset input terminal
can also be used to enter the calibrate mode if “EXT CAL YES” was selected during the Setup procedure.
Activate the input until completion of the “Setpoint Display” sequence.)
•Thetransmitter performsthe Zeroadjustments, then signals theoperator when to applyand also when
to remove the calibration gas. Upon completion of a successful calibration, the transmitter automatically
returns to the Normal operating mode.
•Iftheoperatorfailstocompletethecalibrationprocedure,ifanerrorincalibratingoccurs,orifasuccessful
calibration cannot be completed, the transmitter will automatically return to the Normal mode and continue
to use the previous calibration data (after 10 minutes or when the gas level drops below the lowest alarm
setpoint). A fault indication will be displayed until a reset occurs.
•Ifthemicroprocessordeterminesthatthesensorcellisapproachingtheendofitsusefullife,themessage
“SENSOR” “AT E.O.L.” will be indicated on the display. A fault indication will be displayed until a reset
occurs.
•WhileintheCalibratemode,alltransmitteroutputsareinhibitedandthedccurrentoutputgoestoapreset
level (adjustable from 0 to 20 ma, with a default value of 2.0 ma). See “Setup” section for complete calibration
procedure.
In the setup mode, the range (for some gases), alarm setpoints, calibration gas level, current loop levels,
relay operation (latching/non-latching, energized/de-energized), and calibration mode (auto/manual) are
programmed into the transmitter.
NOTE
When using MOS H
2
S sensors, only 40 ppm H
2
S in air may be used for span calibration.
The transmitter will not read accurately if other concentrations are used.
Operating Mode
Reset
Setpoint Display
Auto Calibration
Setup
Table 4—Inniti Modes of Operation (Continued)