Teledyne 9110TH - Nitrogen Oxides Analyzer - Manual (Page 306)

Model 9110TH NOx Analyzer Principles of Operation
Teledyne Analytical Instruments 286
8.5.6. PNEUMATIC SENSOR BOARD
The flow and pressure sensors of the 9110TH/M are located on a printed circuit
assembly just behind the PMT sensor. Refer to Section 7.5.16 for information on how
to test this assembly. The signals of this board are supplied to the motherboard for
further signal processing. All sensors are linearized in the firmware and can be span
calibrated from the front panel.
8.5.7. RELAY BOARD
The relay board is the central switching and power distribution unit of the analyzer. It
contains power relays, valve drivers and status LEDs for all heated zones and valves, as
well as thermocouple amplifiers, power distribution connectors and the two switching
power supplies of the analyzer. The relay board communicates with the motherboard
over the I
2 C bus and can be used for detailed trouble-shooting of power problems and
valve or heater functionality. See Figure 7-4 for an annotated view of the relay board.
8.5.7.1. Relay PCA Location and Layout
Generally the relay PCA is located in the right-rear quadrant of the analyzer and is
mounted vertically on the back side of the same bracket as the instrument’s DC power
supplies, however the exact location of the relay PCA may differ from model to model
(see Figure 3-5)
8.5.7.2. Heater Control
The heater control loop is illustrated in Figure 8-21. Two thermocouples (T/C) inputs
can be configured for either type-J or type-K thermocouples. Additionally:
 Both T/C’s can be configured as either grounded or ungrounded
thermocouples.
 Standard configuration of the both type of thermocouples is 10 mV/°C. In
order to accommodate the 9110TH’s Mini High-Con converter option, a
type-K; 5mV/°C output configuration has been added.