Advertisement
• TJ mode
The relationships between the acceleration pulse, deceleration pulse, and brake interval are as shown in the table
below.
Command
1 TRACK JUMP IN (OUT) #1
1 TRACK JUMP IN (OUT) #2
1 TRACK JUMP IN (OUT) #3
1 TRACK JUMP IN (OUT) #4
2 TRACK JUMP IN (OUT)
4 TRACK JUMP IN (OUT)
16 TRACK JUMP IN (OUT)
32 TRACK JUMP IN (OUT)
64 TRACK JUMP IN (OUT)
128 TRACK JUMP IN (OUT)
256 TRACK JUMP IN (OUT)
TRACK JUMP BRAKE
* The 256 TRACK CHECK does not produce an actuator drive signal as shown in the table above, rather because the
mode is such that the TES signal is counted when the tracking loop is off, it is necessary to provide a feed to the feed
motor.
* When the track jump sequence (a, b, c) is completed, the servo command register is reset automatically.
* When a new command has been input when the track jump is in process, that command is executed at that instant.
* In the 1 TRACK JUMP #3 command there is no brake period (period c), but rather caution is warranted because it is
necessary to generate the brake mode using an external circuit.
* Although in the 2TRACK JUMP IN (OUT) of the new track jump mode the brake period (period c) did not exist for
the LC78620E/21E/25E ICs, in this IC period C has been changed to 60 ms.
LC78626KE
When in the conventional track jump mode
a
b
233 µs
233 µs
0.5 TRACK
233 µs
JUMP period
0.5 TRACK
233 µs
JUMP period
0.5 TRACK
233 µs
JUMP period
None
2 TRACK
466 µs
JUMP period
9 TRACK
7 TRACK
JUMP period
JUMP period
18 TRACK
14 TRACK
JUMP period
JUMP period
36 TRACK
28 TRACK
JUMP period
JUMP period
72 TRACK
56 TRACK
JUMP period
JUMP period
TOFF is high during the period over
which 256 tracks elapse and pulses a
and b are not produced
There is no a or b period
Slip detector
High during the brake interval
When in the new track jump mode
c
a
60 ms
Same as in the conventional mode
0.5 TRACK
60 ms
JUMP period
This period
0.5 TRACK
does not exist
JUMP period
60 ms TOFF ="L"
0.5 TRACK
during period C
JUMP period
1 TRACK
JUMP period
2 TRACK
60 ms
JUMP period
9 TRACK
60 ms
JUMP period
60 ms
Same as in the conventional mode
60 ms
Same as in the conventional mode
60 ms
Same as in the conventional mode
60 ms
Same as in the conventional mode
60 ms
Same as in the conventional mode
b
c
The same
60 ms
as for a
The same
This period
as for a
does not exist
The same
60 ms TOFF ="L"
as for a
during period C
The same
60 ms
as for a
The same
60 ms
as for a
The same
60 ms
as for a
No. 5995-17/34
Advertisement
