Theory of Operation
Communications 2
2-5
Victoreen Communications Loop – 943-227-15VL
Communication between the detector preamplifier and the UDR or 960 controller may be performed via
Victoreen loop, a serial asynchronous communications interface. The communication utilizes Victoreen
protocol and is intended for use in electrically hostile environments where high noise immunity is required.
Noise immunity is achieved using differential line driving, and electrically isolating the end of each
transmit/receive pair with opto-isolators. Using a ±15 Vdc communications power supply, each 0 to 1
transition is equivalent to a 30-volt swing in loop voltage. Refer to the Model 942-200-80-1
Communications Board instruction manual for further information.
Jumper JP1 controls the communication communications method employed. JP1, A-B selects Victoreen
loop communications.
RS232C Communications – 943-227-15
Communication between the detector preamplifier and the UDR or 960 controller may be performed via
RS232C serial asynchronous communications interface. Jumper JP1 controls the communication
communications method employed.
JP1, B-C selects RS232C communications.
Switch and jumper settings for the preamplifier are summarized in Table 2-7, 2-8, and 2-9.
Table 2-7. Preamplifier Serial Interface Board 977-210-10M Switch Settings
Switch Normal
Op. Switch Function
SW1 Open Microprocessor Reset switch, momentary contac
t
SW2 N/A Not supplied
SW3-1 ON OFF Selects 300 baud • 1/ON Selects 4800 baud (normal setting)
SW3-2 OFF OFF • (No function is implemented in the 977-210-10M)
SW3-3 OFF OFF Selects Rate Mode (normal) • (Selects Maintenance Mode for
factory PGA and Auto Zero set-up only)
SW3-4 OFF OFF • (No function is implemented in the 977-210-10M)
NOTE
SW3 is a 4-position DIP switch on the 977-210-10M serial
interface board.