TrueTime 151-600, Manual

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X X L L D D C C M M A A N N . . d d o o c c 1 1 - - 8 8 R R E E V V E E
1-34 SLOW CODE OUTPUT (OPTION)
This output option is connected to a rear panel BNC connector. This output provides one pulse per
minute, primarily for placing timing marks on drum recorders. Each pulse edge is aligned to within a
few nanoseconds of the XL-DC’s 1 PPS output pulse, with the rising edge at the start of the minute.
The as shipped default values are:
Once per minute = 2 seconds
Once per hour = 4 seconds
Once per day
= 6 seconds
Refer to Keypad and Serial Function 17 for detailed information on "SLOW CODE SETUP". The output
is HCTTL levels and will drive up to 100
Ω or will drive up to 15 LSTTL loads.
Programmable
Pulse Widths:
On the Minute, On the Hour, On the Day (See Function 17)
Drive: HCMOS
Accuracy: 150 ns to UTC, 100 ns without SA
1-35 PRECISION 60 PPS OUTPUT (OPTION)
This output option is connected to a rear panel BNC connector. It is intended to be a frequency source
for driving a synchronous motor through a power amplifier. This option would allow a drum recorder to
be kept synchronized to the correct time, independent of local power line frequency variations. The
output is a quasi-square wave with an unusual duty cycle. It is 50% over a period of 50 ms, or 3 cycles.
The cycle timings are:
cycle #1 high 9 ms, low 8 ms
cycle #2 high 8 ms, low 9 ms
cycle #3 high 8 ms, low 8 ms
The output is HCTTL levels and will drive up to 100 Ω or will drive up to 15 LSTTL loads.
Waveform: 50% over 50 ms, or 3 cycles
Amplitude: TTL Levels
Drive: HCMOS
1-36 ALARM OUTPUT-OPEN COLLECTOR (OPTION)
The Alarm Output option is connected to a rear panel BNC connector. This output is controlled by
Keypad or Serial Function 73 “REQUEST/SET ALARM STATUS/CONTROL”. The open collector
alarm output has the following states:
Off (High Z) Power off
Off (High Z) Error, major or minor enabled alarm fault
On (Low Z) Normal, no major or minor enabled alarm faults