SenSmart 3000 User's Manual
Document: UM-1003
Revision Level B
15
during calibration process and when an alarm is present. It will stay on for 15 seconds after any
of these events clear.
3.2
Initial Bridge Sensor Monitor Start-Up
SenSmart 3000 LEL Monitors that are factory equipped with a local Simple or Smart Bridge
sensor rarely require adjustments, other than routine calibrations, to provide accurate LEL
readings. However, after installation the following checks should be performed to insure proper
operation. In addition, alarm levels, Measurement Name ASCII fields and other variables may
require configuration by users in order to best serve their application.
3.2.1 Initial Bridge Sensor
Monitor “Sensor Volts” Check
CAUTION: Sensor Volts
in excess of the rated values may destroy catalytic bead sensors.
SenSmart 3000 sensors are rated for 2 volts.
Section 6.2 describes reading and setting “sensor volts” using the SenSmart 3000 LCD. The
voltage displayed on the LCD is monitored across TB1-REF and TB1-ACT on the SenSmart 3000
Power Supply board (Figure 2.4) and may be confirmed with a voltmeter. This TB-1 value is
correct for locally mounted sensors only. Sensors mounted more than a few feet away from the
SenSmart 3000 may receive a lower voltage due to the inherent voltage drop across sensor
wiring. Remote mounted sensors must have their sensor voltage (across ACTIVE and
REFERENCE beads) measured AT THE SENSOR end of the cable. The SenSmart 3000 setting
will require a higher value in order to achieve the correct voltage at the sensor. Correct sensor
voltage should be confirmed after start-up for locally and remotely mounted catalytic bead
sensors.
3.2.2 Initial Bridge Sensor
Monitor “Balance” Check
Catalytic bead sensors connect to a bridge circuit that may require a balance adjustment after
installation especially when the sensor is remote mounted from the SenSmart 3000. Section 6.2
describes using the LCD to read and adjust BALANCE settings. Correct BALANCE setting should
be confirmed after start-up for locally and remotely mounted catalytic bead sensors.
3.2.3 Initial Bridge Sensor
Monitor “Span” Check
Prior to the initial
Routine Sensor Calibration
described in section 4.1, a coarse SPAN gas
reading verification should be performed after installation. After correct Sensor Volts and
BALANCE have been verified, apply an upscale gas value such as 50% LEL to the sensor. The
indicated value should read between 35 and 65% LEL with 50% LEL gas applied. Larger errors
may indicate incorrect sensor wiring or defective sensor. Remember that this is only a coarse
check and precision calibrations are performed in
Routine Sensor Calibrations
described in the
following section 4.1. Section 6.4 describes PREAMP GAIN adjustments that may be required if
full-scale ranges are changed.
3.3
Initial Toxic / Oxygen Sensor Monitor Start-Up
SenSmart 3000 Toxic / Oxygen Monitors, factory equipped with a local Simple or Smart
electrochemical sensor, rarely require adjustments (other than routine calibrations) to provide
accurate readings. However, after installation the following checks should be performed to insure
proper operation. In addition, alarm levels, Measurement Name ASCII fields and other variables
may require attention by users in order to best serve their application.
3.3.1 Initial Toxic / Oxygen Sensor
Monitor “Span” Check
Prior to the initial
Routine Sensor Calibration
described in section 4.1, a coarse SPAN gas
reading verification should be performed after installation. Apply an upscale gas value of at least
25% of full scale to the sensor. For example, if 0-100ppm H2S is the measurement range, apply
