RC Systems ViewSmart 1600+ Operation Manual page 29

This option may also be configured to accept 4-20mA inputs for mixing bridge sensors and current loops
into the same board. Placing any channel's 2 position Bridge/4-20mA jumper into 4-20mA position and
installing the associated precision 100 ohm socketed resistor allows 4-20mA signals to be applied to its C
& A terminals. The 10-0192 sensor modules are not required for channels accepting 4-20mA.
After performing the one time only Bridge Sensor Input Board Initial Setup as described below, all
subsequent calibrations are by the ViewSmart 1600+'s electronic Cal Mode menus.
After initial setup, configuration setting of a channel for a bridge input can be found in Chapter 4.3.2.
*Catalytic sensors connected directly to the ViewSmart 1600+ should be limited to ranges of 0-1000ppm.
3.4.2.1 Bridge Sensor Input Board 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.
Prior to connecting sensors:
1. Apply power to the system.
2. Measure the voltage between each channel's A and R terminals
3. 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.
4. Remove system power
5. Connect sensor wires to the R-C-A terminals as described in the previous section.
6. Apply system power
7. 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 power losses in the wiring.
8. Measure voltage at the channel's red test point, TB3 common as your common.
9. Adjust the Balance potentiometer for .4 volts at the test point, with zero air on that sensor.
10. Apply 50% span gas to the sensor and allow the test point voltage to stabilize.
! Note: Two volts = 100% input to the A – D Converter and .4 volts = 0%. Therefore, 1.2 volts = 50%.
11. Place the 3 position Coarse Gain jumper into the position which reads between .8 volts and 1.2
volts on the test point with 50% gas on the sensor.
UM-1097
Revision B 19