AMETEK 952 BlueOx LDT - Manual (Page 13)

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Figure 3-6: 952 RS Start/Stop Pulses
INPUT (INTERROGATION PULSE)
1 MICROSECOND (RECOMMENDED)
0.2 MICROSECONDS (MINIMUM)
TIME BETWEEN PULSES IS PROPORTIONAL TO
DISTANCE BETWEEN MAGNET AND HEX HEAD
OUTPUT (START PULSE) OUTPUT (STOP PULSE)
WITHIN 50 NANOSECONDS AFTER INTERROGATION
PULSE, START PULSE BEGINS
3.8: 952 RS (Start/Stop)
The start/stop signal interface of the BlueOx digital
output series is differential RS-422 output. The
maximum cable length for differential LDTs is 1,500
feet. To initiate a start pulse, an external device is
used. This start pulse should be a minimum of 1.0
microsecond in duration. Within 50 nanoseconds
after the leading edge of the start pulse, the LDT
will generate a start pulse of 1.0 microsecond
in duration. A stop pulse of 1.0 microsecond in
duration will follow. The time it takes from the
leading edge of the start pulse to the leading edge
of the stop pulse is proportional to the distance
between the magnet to the hex head. The order of
these two pulses is illustrated in Figure 3-6. To wire
the 952RS, see Figure 3-7. For proper grounding
information, see the beginning of this chapter.