Tz Drive Board; Service Switches - Hologic QDR 4500 Technical Manual

Table 2-3. Motor Controller Board/Stepper Motor and Position Encoder
Interconnection Descriptions
Signal
(No label) Motor drive signals (4).
+REF Precision positive voltage to position potentiometer.
(No label) Position encoder wiper return voltage.
-REF Precision negative voltage to position potentiometer.

TZ DRIVE BOARD

The TZ Drive Board is a microprocessor controlled power driver circuit for the two pedestal
motors which raise and lower the patient table in the QDR 4500A and SL. This board is located
in the electronics tray in the bottom of the Scanner base assembly.
The TZ Drive board communicates with the communications controller, via the Distribution
board, to drive the pedestal motors under computer control. Manual raising of the pedestal may
be required in case of an emergency. In this case, manual control is provided through the Table
switch of the Scanner's Operator Control Panel.
The TZ Drive board monitors the position of each pedestal using signals received from an
associated Position Encoder connected to the respective pedestal.

Service Switches

The TZ Drive board contains four service switches used during replacement of a defective
pedestal or Position Encoder. Table 2-4 describes these switches and their respective functions.
CAUTION: The TZ drive motors are designed to run at a 5% duty cycle. If the motors overheat,
the built-in thermal cutouts may trip and cause the motors to stop functioning. If
this happens, you must wait about 20 minutes before functionality is restored. See
the heading Unable to position device within specified tolerance... on page 6-45.
Table 2-4. TZ Drive Service Switches
Switch
Mode
(Normal/Service)
Direction (Up/Down)
Left
Section 2 - Functional Description
Description
Determines whether the TZ Drive is in Normal or Service operation.
When the TZ drive is in Service mode, determines the direction of pedestal
movement (not active in normal mode).
When the TZ drive is in Service mode, moves the left pedestal in the
direction specified by the Direction switch (not active in normal mode).
JP5-1 - JP5-4
JP3-1
JP3-3
JP3-5
Function
Pin
2-7