Digital Output Board; I/O Expansion Board (Optional) - Thermo Scientific 49i Instruction Manual

Flow Sensor Assembly
Pressure Sensor Assembly
Ozonator Lamp Power Supply
Photometer Lamp Power Supply

Digital Output Board

I/O Expansion Board
(Optional)
Thermo Fisher Scientific
The flow sensor assembly consists of a board containing an instrumentation
amplifier and a flow transducer with input and output gas fittings. The flow
transducer output is produced by measuring the pressure difference across a
precision orifice. This unit is used for measuring the flow of sample gas in
the measurement system.
The pressure sensor assembly consists of a board containing an
instrumentation amplifier and a pressure transducer with a gas input fitting.
The pressure transducer output is produced by measuring the pressure
difference between the sample gas pressure and ambient air pressure.
The ozonator lamp power supply board includes the circuits that generate
high voltage AC to control the lamp heater. A transformer outputting high
voltage at approximately 15 kHz drives the lamp. A resistor in series with
the output limits the lamp current. The voltage output is adjustable under
software control for lamp intensity control. The ozonator lamp can be
switched on and off under software control.
The lamp is heated to a specific temperature to ensure reliable operation.
The oscillator circuit that drives the high voltage output is inhibited until
this operating temperature is reached. A power transistor is used to heat the
lamp housing. Thermistors sense the housing temperature for heater control
and for status information.
The photometer lamp power supply is similar to the ozonator power supply
except for the operating temperature set point and the value of the resistor
in series with the output. The photometer is always "on" when the
operating temperature is reached. Software on/off control is not required.
The digital output board connects to the motherboard and provides
solenoid driver outputs and relay contact outputs to a connector located on
the rear panel of the instrument. Ten relay contacts normally open (with
power off ) are provided which are electrically isolated from each other.
Eight solenoid driver outputs (open collector) are provided along with a
corresponding +24VDC supply pin on the connector.
The I/O expansion board connects to the motherboard and adds the
capability to input external analog voltage inputs and to output analog
currents via a connector located on the rear panel of the instrument. It
contains local power supplies, a DC/DC isolator supply, a sub-processor
System Description
Electronics
Model 49i Instruction Manual 8-7