THEORY OF OPERATION Chapter 2
2 - 9
2.2.3.3 Barrel Position Detector
Barrel position detection is provided by two membrane switches connected in series in the
barrel clamp assembly. Each switch is activated by pressure of the syringe barrel on its
respective half of the barrel cradle. Both switches must be activated to bring “BARREL*”
low. This signal passes through the zebra strip connector to the I/O board to the digital
board on P2A-2 as “BARREL*”.
2.2.4 Syringe Plunger Position and Capture Detector
2.2.4.1 Plunger Position
Syringe plunger position is detected by linking the plunger driver to a soft-pot in the plunger
driver mechanism. The system provides power and receives signal from the soft-pot via
J7. The soft-pot wiper is named “LINEAR_POS” on the digital board.
2.2.4.2 Plunger Capture
Syringe plunger capture is detected by a mechanism in the plunger driver that disengages
the wiper from the soft-pot when the syringe plunger is not properly engaged in the driver.
When this happens R59 will pull “LINEAR_POS” to 0 volts which software then detects as
loss of plunger capture.
2.2.5 Motor/Gearbox/Encoder
The pump makes use of a Micro-Mo DC Micromotor series 1524 with integral encoder and
gear box part number 1524E006S123 155 485:1 HEM1524E16. It is a 6.0 volt 0.81 watt
brushed motor with a 16 pulse per revolution encoder and a 485:1 gear box.
2.2.6 Audio Transducer
The audio transducer is a piezo ceramic transducer. It is driven at either 4 kHz for normal
tones or an oscillating 4 kHz to 2 kHz for fail-safe alarms. The control and drive circuitry for
the transducer is located on the analog board and is routed to the speaker via the I/O
board.
2.2.7 Charger
The Charger C-AS40-01-900 is an unregulated wall plug transformer. It is specified as a
nominal output of 12.6 volts peak at a load current of 250 mA with 115 VAC input. It
behaves as a simple 16.1 volt source in series with a 13.5 ohm resistor with a nominal 115
VAC input.
To Next Page
Loading...
Need help?
General
