Fluke Biomedical 942A-200L-M4 - Manual (Page 39)

Theory of Operation
Optional Circuit Boards
2
2-25
2.7 Optional Circuit Boards
Option circuit boards are installed into the 50-pin J3 connector available on the main circuit board. As
many as three option boards may be stacked into the J3 bus. The following paragraphs describe the
available options. A separate manual, for each option board, is available with more detailed information.
Listed below are the option boards currently available.
1. 942-200-75: ANALOG OPTION INPUT BOARD - Contains four separate channels for analog input.
A 0 to 10 VDC input or 4 to 20 mA input can be selected independently for each channel using the
jumpers and switches provided on the board. Possible inputs to the board include: temperature,
pressure, flow, or simulated radiation.
2. 942-200-80: COMMUNICATIONS LOOP OPTION BOARD - Designed to enable a communications
link between VICTOREEN’s ratemeter and a user computer system or CRT terminal, with baud
rates ranging from 50 baud to 19200 baud. An asynchronous communication interface adapter is
utilized to format the data and control the interface.
The VICTOREEN communications interface also provides the necessary circuitry to allow
interconnecting to a standard VICTOREEN communication link. This interface allows multiple
UDRs to share a common six-wire cable to a main central processor unit.
3. 942-200-90 and 942-200-90-M1: SINGLE CHANNEL ANALYZER (AMERICIUM REGULATOR) -
Designed to provide two independently adjustable windows for the discrimination of radiation pulses
using the voltage peak analysis technique. When used with an Americium -231 doped sodium
iodine crystal, provides the ability to automatically adjust the detector high voltage to compensate
for photomultiplier tube gain changes due to ambient temperature variations. (A separate channel
is utilized to regulate system gain via the high voltage supply. This channel is locked to an
americium pulse within the detector and is used to maintain a constant gain.)
This channel includes a 16-bit counter. The counter control and sample period functions under
MPU control. A selector switch allows the user to select channel display on the front panel.
For the 942A-200L-M4, the Model 942-200-90-M1 Single Channel Analyzer circuit board is
provided. The –M1 modification suffix identified the circuit board has been modified to permit
transferring from Gross to SCA mode via a Front Panel mounted switch.
4. 942-200-95: ANALOG OUTPUT BOARD - Designed to provide a user selectable single output
voltage of: 0 -10 VDC, 0 -5 VDC, 0 -1 VDC, 0 -500 mV DC, 0 -100 mV DC, 0 -50 mV DV, or 0-10m
VDC.
5. 942-200-95M1: DUAL ANALOG OUTPUT BOARD - Designed to provide two user selectable output
voltages. Output #1 is either 0 -5 VDC, or 0 -10 VDC, while output #2 is either 0 -10 mV DC, 0 -50
mV DC, 0 -100 mV DC, 0 -500 mV DC, or 0 -1 VDC.
For the 942A-200L-M4, the Model 942-200-95-M1 Dual Analog Output circuit board is provided.
The –M1 modification suffix identified the circuit board has been modified to provide two additional
analog outputs with a voltage range of 0-10mV and 0-5 VDC