GDS C1, Инструкция по эксплуатации

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Channels receiving input data from this board should have the Data From: menu set for
Sensor, as described in section 2.2.4. This activates Cal Mode menus described in
section 2.2.7 needed to zero and span sensor readings. After performing the one time
only Initial Setup as described below, all subsequent calibrations are by the C1’s
electronic Cal Mode menus.
*Catalytic sensors connected directly to the C1 should be limited to ranges of 0-
1000ppm.
3.1.4 CATALYTIC BEAD SENSOR INITIAL SETUP
Catalytic bead sensors vary widely in power requirements and sensitivity. It is therefore
important to configure each channel to match the sensor with which it will operate.
1. Prior to connecting sensors, apply power to the system. Note this PCB requires
24VDC power be connected to its TB2 terminals 1 & 2 as shown in Figure 3.5.
Suitable fused power is available from the Main I/O board’s TB2 terminal 10 &
12 (see Figure 3.1). Measure the voltage between each channel’s A and R
terminals and set the
Voltage Adjust potentiometers for the correct sensor
excitation voltage. This may range from 1.5 volts to 7.5 volts depending upon
sensor specifications.
Sensors may be damaged by accidental over voltage
conditions. It is recommended the Voltage Adjust potentiometer screws be
covered by a dollop of RTV or similar material after completion of this
procedure to avoid accidental over voltage conditions.
2. Remove system power and connect sensor wires to the R-C-A terminals. Reapply
system power and confirm correct voltage across each sensor’s A & R terminals.
Note: If sensor wires are long, it may be necessary to measure the excitation
voltage at the sensor end to compensate for I
2
R losses in the wiring.
3. With the minus voltmeter lead on TB2-2 (common), connect the plus lead to the
channel’s test point. With zero air on that sensor, adjust its
Balance
potentiometer for .4 volts at the test point.
4. Apply 50% LEL combustible span gas to the sensor and allow the test point
voltage to stabilize. Two volts = 100% input to the A – D Converter and .4 volts
= 0%. Therefore, 1.2 volts = 50%. Place the 3 position
Coarse LEL Gain jumper
into the position which reads between .8 volts and 1.2 volts on the test point with
50% LEL gas on the sensor. Gain settings for each jumper position are as
follows: no jumper = 1, LOW = 7, MED = 21, HI = 41. Multiple jumpers have
an additive affect upon gain, so the LOW and MED jumpers together provide a
gain of 28.
Initial setup is now complete and normally only requires repeating if a sensor is replaced.
Final calibration of this channel may now be performed using the C1’s electronic Cal
Mode feature described in section 2.2.1.
!