Service manual

PN 4237242C
2.4-6
INSTRUMENT DESCRIPTION
SYSTEM CONTROL
Switches and Jumpers
Diluter Resource Adapter (DRA) Card
The DRA card is located in the upper chassis (Figure 2.2-1) and is a hardware interface
between the AT motherboard and the Fluidics Panel motors and solenoids. This includes the
vacuum pump, cycle counter and lyse pump, which are treated as solenoids by the software.
There are two DRA cards used in the MD II Series and each allows the CPU to control up to
four stepper motors and 14 solenoids. To accomplish its task, the card has two motor
controllers and one solenoid controller, as well as support circuitry.
The DRA’s output connectors are summarized in Table 2.4-3 and the jumper settings are
summarized in Table 2.4-4. Figure 2.4-3 shows the location of the connectors and the
location and setting of the jumpers. Tables 2.4-3 and 2.4-4 and Figure 2.4-3 are at the end of
the description of the DRA card.
Motor Controller
The motor controller has two control circuits, each capable of interfacing with one motor and
one solenoid. Each controller has one buffered connector, two multitimers, two logic
elements and two command latches with command and status readback buffer. A motor
sensor buffer is also provided as part of the motor controller package.
The motor controller connector delivers the motor phase signals for two motors and the
energize command for two solenoids to the Motor/Solenoid Driver card. It also can receive up
to 6-sensor signals. To protect the logic elements of the Motor Controller circuit, buffers are
placed between this connector and the logic element. This provides electrical isolation from
the motor phase output and the sensor input.
A multitimer is assigned to each motor. They are 8254 programmable devices with three
timers. One timer is programmed with the motor step rate or frequency, the second is
programmed with the number of steps, and the third timer is unused.
The logic control for each motor is a GAL 22v10. This device takes parameter input from the
CPU for the motor rate, direction step mode and sensor mode (STOP on sensor or not). It
also receives commands to STOP or ENABLE a motor, or not and can receive input from one
sensor. This input allows the GAL to produce phase signals, control power, and generate an
interrupt when a motor task is completed. The end of task interrupt (IRQ11 for DRA1 and
IRQ12 for DRA2) is generated when sensor has been reached or the 8254 timer has counted
the steps that it was programmed with.
Table 2.4-2 URA Card Switch and Jumper Settings
Switch or Jumper Description MD II Setting
SW1-1 OFF - COULTER MICRO-PAK reagent
ON - Bulk reagent
OFF
SW1-2 OFF - Does not create INF file
ON - Creates INF file
OFF
SW1-3 OFF - Normal operation
ON - Final test functions
OFF
SW1-4 OFF - Normal operation
ON - Adds Service Report when SW1-3 is ON
OFF
SW1-5 to SW1-8 Not used OFF
X1 Connects oscillator to circuitry ON