Fluke Biomedical 945A - Manual (Page 12)

Universal Digital Ratemeter, Model 946A-200
The Victoreen Model 946A-200 Universal Digital Ratemeter (UDR), when connected to a Model 977-210
Ion Chamber Detector, comprises a monitoring system which operates in the range of 10-1 to 107 mR/h.
The UDR provides display, control, and annunciation functions for the monitoring system. Refer to Figure
1-2 for view of the 946A-200 front panel.
Standard features for the instrument consist of a three digit display of the radiation value and a multi-
colored bargraph indicator which covers the entire range of the detector. The bargraph will change color
in the event of an alarm condition. Front panel alarm indicators and rear panel output relays for alarm
annunciation are also included. Front panel pushbuttons are provided to apply power, display alarm limit
set points, for alarm acknowledgment, and the activation of a check source function.
Analog outputs of 0 to 10 VDC and 4 to 20 mA (2) are provided for recording and computer monitoring.
The 0 to 10 VDC output may also be used to drive a remote meter or a local (i.e. near the detector)
indicator.
All electronics required to interface to the VICTOREEN 977-210 series detector/preamplifier are included
within the 946A-200 UDR. These electronics consist of a low voltage power supply, and the
hardware/software required for UDR operation. The system also includes a positive overrange indication
on the display when radiation intensity exceeds the full scale value of 10
7
mR/h.
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 - (Generally not used for normal operation with the 946A-200
UDR, however, it is used if the UDR is part of a simulator) 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 EIA RS232C serial
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 Communication Loop Option Board also provides an isolated multi-drop, serial communications port for
interface with a supervisory computer system. The serial data is in a modified RS232 format, and utilizes
Victoreen’s proprietary VICO loop protocol. For maximum electrical noise protection, a six conductor
communication cable is used.
The 946A-200 UDR has one standard 942-200-80 Communications Board to support communications between
the preamplifier and the 977-210 Detector/Preamplifier.
3. 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 mVdc, 0 - 100 mVdc, 0 - 50 mVdc, or 0 - 10 mVdc.
4. 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 mVdc, 0 - 100 mVdc, 0 -
500 mVdc, or 0 - 1 Vdc.
1-4