Maximum Response Speed; Alarm Signal - Sony MJ100 Instruction Manual

3-5. Maximum Response Speed

The output phase difference of the MJ100 changes
continuously in increments of 100 ns beginning from 100 ns
for the MJ100 and in increments of 100 ns beginning from
1 us for the MJ110.
Since the maximum response speed is determined by the
output phase difference and resolution, the correlation
between these factors is as shown in the graph in Fig. 5-1.
The alarm signal is generated when the maximum
response speed is exceeded.
Although the alarm signal is output when the minimum
phase difference falls below 100 ns (MJ100) or 1 us
(MJ110) , it may be output even when the phase difference
is higher than this if acceleration is excessive.
Note
Although the open collector output signal of the MJ110
varies depending on the cable length and load resistance,
the output may not be able to follow quick fluctuations in
timing depending on the performance of internal ICs. For
this reason, the A/B quadrature signals may not be output
normally and may be unreceivable by the receiver during
that time before the speed alarm is output. (See 3-2-3
regarding output phase difference.) For the MJ110, an
alarm signal is output when the phase difference falls below
1 us.

3-6. Alarm signal

The alarm signal is output for approximately 400 ms when
the travel speed of the scale has exceeded the maximum
response speed, when the signal level from the detector
head is lower than a specified value, when the head cable
has been severed, or when the unit malfunctions due to
external noise or some other reason. The alarm signal is
automatically released after approximately 400 ms if the
cause of the alarm is cleared during this time. If alarm
status continues for more than 400 ms, it will be released
once the cause of the alarm has been cleared.
When an alarm is output, the alarm lamp will light and AL
output of the MJ100 will go high and *AL output will go low.
PCA, *PCA, PCB and *PCB output will go high impedance
at this time.
AL output of the MJ110 will go high (off).
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