SIGMA BM-286A - Manual (Page 33)

4. THEORY OF OPERATION page 30
Model BM-286A
4.2.4. Channel Card, RCS-110:
Refer to "RCS-110 Schematic Diagram" Drawing 6 and "RCS-110 Component Designator"
Drawing 7 (Appendix F.).
VR1, VR2, and VR3 regulate the ±15 volt power supply voltages to ±12 volts and +5 volts for
use on this card. The card is equipped with a series of test points for discriminator, pulse
amplitude, and high voltage measurements. The high voltage test point is a 100 to 1 divider.
U12, U13, and the associated circuitry make up the regulated high voltage power supply. High
voltage (less than 1,500Vdc) is supplied to the MHV connector on the backplane via the 44 pin
edge card connector.
Pulses from the detectors are input through shielded MHV cables to the rack control module, and
then into the inputs on the backplane to the channel boards. The analog signal is decoupled by
C46, amplified by U8 and U7, and sent to the single channel analyzer. The second
amplifier/SCA channels are not used in this application.
The SCA is made up of two voltage comparators (U6). The amplified signal must fall between
the LLD and ULD levels to be digitized and sent to the counters in the computer. These voltages
can be manually adjusted, or set by the computer. In either case, the actual adjustment is done
on the RCS-120 card.
Any pulses having an amplitude greater than the LLD and less than the ULD pass through the
comparator circuits and generate a digital pulse (U10). These pulses are sent to a differential line
transmitter (U2) and on to the line receivers on the CIF-553 Computer Interface board, which
plugs into the ISA bus in the computer.