MPI 40 Series - Page 92

6.3 SELECT DRIVE WITHOUT LOADING HEAPS OR ENABLING STEPPER
In the standard configuration, the heads are loaded and the stepper
motor is energized when DRIVE SELECT is enabled. With this option the user
may keep the drive selected all the time so that the output status can be
monitored while the heads are unloaded, which will extend head and media life.
Heads can be loaded when required by activating the HEAD LOAD interface line
(pin 18) which also will enable the stepper motor. After the HEAD LOAD line
is activated, a 35 ms delay is required before WRITE GATE and WRITE DATA are
applied to the drive or before READ DATA is valid. This delay is the head
load time.
If more that one drive is assigned to the controller, separate I/O pins should
be used as HEAD LOAD lines for each drive. These unused I/O pins need to be
connected to jumper-pin C3. This can be accomplished by soldering a wire
between the unused pin and CJ.
Pin 2, pin 6, and pin 8 can be used to implement this option, however certain
restrictions will apply. Pins 6 and 8 are spares, but pin 2 can also be
used as an external write current switch. When used as a head load line its
alternate function can not be implemented (refer to paragraph 3.5.3).
To install this option on a standard drive, the following jumpers must be
added and deleted. Figure 6-4 illustrates this option.
A. Remove jumper Ll8 - Ml8
B. Install jumper C3 - C4
18
HEAD LOAD -- 1
2 };
HEAD LOAD - 2 ----D===-~7;===---·:-'
HEAD LOAD - 3 -
6
---D:=:(,/
8 ,l,'
HEAD LOAD - 4 0:~'
Figure 6-4:
6-4
'!..>--""°• + DRIVE SELECT
~(~::-t
+HEAD LOAD