DIGIVAC 201 series Instruction Manual Page 3
1.0 DESCRIPTION AND PRINCIPLE OF OPERATION.
The Model 200 Pirani is a full featured vacuum instrument that is fast, accurate and rugged. This unit
builds on the engineering philosophy that made the Model 200 our best selling vacuum instrument:
simple is best and robust is a must. The model 200 Pirani employs a VRC Pirani tube instead of a
Varian 531 gauge tube. The instrument features large, bright LEDs visible from across the room with a
hard, vinyl clad metal enclosure. This entry into our gauge line-up, enables the user to choose yet
another sensor option to best meet their vacuum requirements. The straight forward design yields a low
power instrument, that is simple to build and simple to operate. The low power feature reduces thermal
effects, to improve repeatability. Unlike many other Pirani gauges on the market, this unit has been
recently redesigned with newer, more reliable components to insure a long product life. The Model 200
Pirani can be ordered with optional control relays, analog output, and RS232 output, to simplify
integration with existing process controllers or computers. In addition, this device can be Ethernet
enabled, to allow monitoring via a web browser with our free ReAct browser software. Get access to your
instrument from across the hall, or across the world. All instruments leave our factory tested and
calibrated under real vacuum against a NIST standard.
2.0 CONSTRUCTION.
The controller consists of the indicating and controlling instrument, the sensor configured, the sensor
cable, the output interfaces and an international AC power adapter.
The instrument is housed in a rugged free-standing vinyl clad metal enclosure. It can be placed on a
suitable surface for easy viewing from across the room. The gauge tube houses the various Pirani
sensing, heating and compensating elements and terminates in an octal connector. On this model, the
connector wiring terminates at the instrument with a 9 pin DSub connection. Regulating circuitry in the
DIGIVAC provides constant current for gauge tube excitation, and thus compensates for resistance in
the probe leads.
3.0 UNPACKING AND INSPECTION.
After the instrument is received, it should be carefully unpacked and inspected for damage during
shipment and for completeness. The package should contain, as a minimum, the instrument, the sensor
and cable ordered, an AC power adapter and an instruction manual. In the event of a loss during
shipment, a claim should immediately be made to the common carrier or the postal service, as
applicable. The DIGIVAC warranty pertains only to the instrument, and does not cover losses in
shipping. Each 200 Pirani should come with:
o
User Manual (this document)
o
Display controller (gray box with red lens)
o
Power supply (international adapter with US plug)
o
Configured Sensors
o
RS232 (optional)
o
RS232 Port
o
5
’ RS232 Cable (phono to Female DB9)
o
Ethernet (optional, includes RS232)
o
Ethernet Port
o
Null modem RS232 converter
o
2’ Ethernet Cable
o
Null Modem Ethernet Cable
o
Configuration CD
4.0 INSTALLATION.
The instrument should be located in a clean, dry environment for best results. The gauge tube cable
should be identified by wire tags or markings specific to your environment.
