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“Latching” and “Non-Latching” until one is selected or a 5 minute timer expires in which case the unit
returns to normal operation.
Step 4. High relay options are set next. The high alarm relay cannot be set to a value lower than the
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low alarm relay setting or higher than 100 (25 for the ST1400 O sensor). The high alarm level is
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displayed in increments of 5 (.5% for the ST1400 O sensor) greater than the low alarm level selected in
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step 1 (21.5 for the ST1400 O sensor) to a maximum of 100 (25% for the ST1400 O sensor). Activate
the magnetic reed switch/CAL/RESET button when the desired level is displayed. The selection is
acknowledged by flashing the selected level on the alphanumeric display.
NOTE:
Steps 2 and 3 are repeated for setting the high alarm relay coil and latch status.
Review Settings
Enter the main menu and activate the magnetic reed switch/CAL/RESET button when prompted for “Review
Relay Settings” with “YES?”. The output current will drop to 3.0mA and the relay settings are displayed.
First the fault alarm settings are displayed and these are fixed as normally “Energized” and “Non-Latching”,
followed by the low alarm settings and high alarm settings. This is a read-only mode, thus changes cannot be
made in this mode. The settings for all three alarm relays are displayed twice and then the unit returns to
normal operation.
It is necessary that reliable monitoring and indicating devices or systems be connected to the transmitter.
These devices must be designed to produce clear visual and audible danger signals when high signal levels
occur. Operating personnel must consider the area to be dangerous until a careful survey of the area has been
conducted with a separate and reliable gas indicating device.
Chapter 3 System Calibration
For accurate performance, the UNI-TRAN Premium Plus should be calibrated to the specific gas of
concern. The concentration of gas corresponding to 100% of full scale is converted to a linear 4 to 20mA
output signal which can be powered from the primary DC supply of the instrument.
Calibration is automatic after manual initiation. The operator initiates the calibration sequence by magnetic
activation of the reed switch or by pressing the internal push-button. The UNI-TRAN Premium Plus then
prompts the operator by LED, current loop signals and the alphanumeric display to apply clean air in order to
set zero, followed by 50% of full scale span calibration gas. The entire procedure requires about 5 minutes to
complete.
If the calibration procedure is not performed correctly, the UNI-TRAN Premium Plus automatically returns to
normal operation using its previous calibration data and the calibration failure is indicated by the STATUS
LED and by a scrolling message on the alphanumeric display.