Publication 5390-001 Revision B
4
Har
v
ard Appar
atus Model 33
T
win Syr
inge Pump User's Man
ual
Features
Pressure and Speed
Pump 33 can deliver up to 53.346 ml/min with a 50 ml syringe, and is capable of pres-
sures of up to 99.5 PSI with a 20 ml syringe.
Independent Syringe Diameters and Rates
In the Proportional Mode, separate syringe types and rates may be set.
Variable Syringes
Enter the inside diameter of the syringes being used.
Modes of Operation
Auto Stop
Both syringes will operate at same rate and stop when either syringe reaches a
limit stop.
Continuous Run
With both syringes operating at same rate, when end of travel is reached, the pump
automatically reverses the direction of travel for both syringes.The external valves,
optionally attached to the syringes, will be automatically activated or deactivated.
Proportional
Pump operates as in Auto Stop,but independent rates and diameters are set for each syringe.
Parallel/Reciprocal Operation
Syringes may pump in the same direction (parallel) or opposite directions (reciprocal).
External Connections
TTL
Allows pump operations to be synchronized with external devices or by a person
at a distance from the pump. Direction of pump travel can be set via a TTL pin.
Also,TTL pins are used to control an external valve for refilling and provide an out-
put to indicate whether or not the pump is running. Additional TTL pins are avail-
able for general use.
RS-232
Multiple pumps can be chained together and remotely controlled from a computer or
any device communicating via RS-232.
Valves
Models MA1-55-3334 and MA1-55-3335 include a valve assembly which allows auto-
matic selection of infusion and refill lines.
Non-Volatile Memory
All operational data entered into the pump from the keypad or requested to be saved
via RS-232, will be stored. On power up, all ettings from when it was powered down
will be recalled and the display will blink until the pump receives its first command.
Stall Detection
An optical detector on each motor is used to verify expected movement of the motors.
If motor is prevented from turning due to jamming or kinking of the tubing, the pump
stops and the display indicates a stall condition by blinking the run light and the
syringe direction light of the stalled syringe. Pump 33 employs a microcontroller
which controls a small step angle stepping motor that drives a lead screw and half nut.
Microstepping techniques are used to further reduce the step angle making flow pul-
sation negligible. A keypad is used for entry of operating data to the pump or data can
be entered via RS-232. The microcontroller calculates the cross-sectional area of the
syringe selected and calibrates the flow rate.
