39
PM3394, FLUKE & PHILIPS
ch4
ch3
ch2
ch1
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CH1!5.00 V=
CH2!5.00 V=
CH3!5.00 V=
CH4!5.00 V= CHP MTB10.0ms- 0.72dv ch1-
1
2
3
4
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The “tray 3” group of waveforms below are taken of the serial communi-
cations occurring when the front panel tray button S212 is pressed. Note
that when comparing these waveforms to the group of “tray 1”, an extra
set of communications takes place 20msec later.
Waveforms Tray 3 = Tray Button Pressed
Name Location Voltage/div
Channel 1 XIFint(interrupt) CN006/pin 2 5Vp-p
Channel 2 Serial data CN006/pin 4 5Vp-p
Channel 3 Serial clock (SCO) CN006/pin 6 5Vp-p
Channel 4 Chip select (CSOL) CN006/pin 3 5Vp-p
Time base 10msec/div.
IC202 Instructs Hybrid Gate Array IC601
System Control IC202 coordinates and controls many operations. A Hy-
brid Gate Array IC601 is used to interface IC202 to other ICs for analog
and digital operations. Information is sent between IC202 and IC601 us-
ing a parallel bus and chip select lines. Communications between these
two ICs occurs when IC202/pins 7 and 10 applies a low to chip select
IC601/pin 142 & 141.
From this communication, the Hybrid Gate Array IC601/pin 92 outputs
the loading motor command using tri-state output. When the output is
open circuited, the loading motor does not turn. A high causes the tray to
open (extend).
IC601/pin 91 is grounded when the tray is out. This low is brought to
IC802/pin 9 to prevent the tray motor from moving (inhibited).
Loading Motor Command
Tray Motion Command Voltage at IC601/pin 92
Stopped 1.6V (open circuit)
Opening 3.2V
Closing 0V
Driver IC802 Translates the Command
Driver IC802 applies the voltage necessary to turn the loading motor.
The loading motor moves the tray. As the tray moves in, the motor pulls
up the laser platform. Tray Drive Voltages
Tray CN011/pin 1 CN011/pin 2
Stopped 5.7V 5.7V
Opening 7.36V 3.5V
Closing 3.6V 7.6
Tray Position Switch Returns Information to IC201
Two switches under the transport on the MS-29 board detect the tray and
laser platform position. Both of these switches return status information
to Interface IC201.
Tray position switch S001 stops the loading motor during tray open. IC601
receives the switch information and opens drive pin 92 to stop the loading
motor. Both S001 and S002 stop the motor during tray close.
Tray Position Switch Voltages
Tray Position Switch S001 Chuck Switch S002
Tray CN011/pin 3 CN011/pin 4 CN011/pin 6
Open 3.2V 0V 3.2V
Closed 0V 3.2V 0V
S001 and S002 switch information pass IC601 and IC202 to IC201:
1. This information completes the tray position logic so the motor can
reverse rotation with each press of the tray button.
2. Activates the loading motor if the user has pushed the tray in.
If IC201 does not receive the correct tray closed or open feedback, the
loading motor will be instructed to reverse direction.