Section 3: Operation ______________________________________________
Page 3-10
8197 Instruction Manual
1
2
3
B
A
N. C.
100-ohm
Termination
Resistor
TTL-Compatible
Input
FIGURE 3-6 SINGLE-ENDED CONNECTION
The 100-ohm termination resistor is required at the cable destination to prevent
ringing and reflections.
3.2.3.2 Major Alarm Contacts
Major Alarm relay contacts are found on Pins 4, 5 and 6 of each timing output
connector. During normal operation, the Major Alarm relay is energized causing
continuity between Pin 4 and Pin 6. When a Major Alarm is asserted the relay is
deactivated causing continuity between Pin 4 and Pin 5. The relay remains in
alarm condition until the condition causing the alarm is corrected or is reset by
the clear alarm, CA, command. Refer to section 3.1.2 for a complete description
of Major Alarms.
3.2.4
Data Clock Timing Outputs
This connector provides RS-485 clock signals of one pulse per second (1PPS),
9.6 kHz, 18 kHz and Major Alarm relay contacts. The connector is a 9-pin series
D numbered as shown in Figure 3-7. Data Clock pin assignments are listed in
Table 3-5.
FIGURE 3-7 DATA CLOCK CONNECTOR
