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Glossary of Terms

Linear Series Actuator Module
The assembly in a linear system that drives the piston in the attached Pump Module. The linear actuator produces separate rotational movement for valving and linear movement for liquid displacement. The linear actuator in a linear system corresponds to the motor/base assembly in a rotary system.

Linear Series System
One of two major types of precision liquid dispensing or metering systems available from IVEK Corporation. The controller of the linear system can separately command the linear (displacement) and rotary (valving) motions of the piston. The liquid displacement is constant over time, limited by acceleration and deceleration at the beginning and end of the motion. The Digispense 3020 and Multispense 2000 are linear systems.

Angular Orientation
This references the orientation of the piston in a rotary system, relative to the motor face, with the piston and cylinder of the Pump Module mounted on the Motor/Base Module. The angular orientation sets the reciprocal stroke travel of the piston.

Bubble Clear
Automatic cycle in a linear system providing a means of removing small bubbles of air or gas from the pump chamber. Selected from the control panel.

Any gauge, meter, pump, etc. that has been systematically checked / adjusted to a known, certified standard.

The sudden formation and collapse of bubbles in liquids by means of mechanical forces creating low pressure.

IVEK offers both single and multiple channel configurations. A channel refers to a single Motor/Base or Actuator Module driven by a Controller Module. Single Channel systems are often bench-top units. Multiple Channel systems are often integrated into a production application to fill many vessels at once.

Clean Liquids
Application liquids or reagents which have been prepared via a filtration, distillation or other sterilization process to a controlled level of acceptable molecular and(or) biological contamination.

Clear Faults

  1. The 'clear faults' command must be issued prior to any commands which would cause motion in a Actuator Module or motion control device in a system which is faulted. This command responds with the identity of the fault being cleared and additional information for certain faults.
  2. To manually reset the system due to any fault condition that may occur.

Command String
A series of characters sent to a controller containing a serial interface to control its operation.

Compatible Liquids
Any liquid that has been evaluated and qualified as having no negative effect on the liquid management system components.

Continuous Meter
Operating mode to produce a continuous liquid flow as long as a control signal (and liquid) is supplied. Note: This mode only applies to the Digifeeder 2002 system and utilizes two pumps driven by linear actuators that alternate in operation between intake and discharge cycles. All other systems use Meter mode.

Controller Module
The module in a system containing the electronics for controlling and monitoring system operations.

Pump Module component where the piston is housed.

Dead Volume
Liquid occupying areas within the system which is not replaced during each cycle or removed during a purge.


  1. The deviation from zero or other neutral value by the indicator of a measurement instrument.
  2. The movement of a structure or structural part as a result of stress.

Generally, referring to the evacuation of free gasses from the application liquid.


  1. Controller mode function used to select forward or reverse motion of liquid flow through the Pump Module and liquid circuit.
  2. For some rotary systems, flow direction can also be changed by adjusting the pump displacement angle to the other side of the "zero" point (zero angle where pump has zero displacement).

Dispense Mode
Controller mode function used to deliver a discrete, specific volume of liquid at a specific flow rate as the result of a triggering action.

Operation which automatically reverses liquid flow at the end of a dispense to improve repeatability and string breaking. The drawback volume is generally a fraction of the dispense volume.

Drive System

  1. The system configuration relative to the controller and Motor/Base Module including electronics, software, drive motor and braketry options.
  2. Mechanical components that transmit power.
  3. Electrical circuitry that controls and powers a motor, solenoid, or other electrical-to-mechanical converter.

Empty Mode
Controller mode function used to return liquid in the inlet tubing, pump chamber, and outlet tubing to the supply reservoir, when metering and(or) dispensing operations are completed.

A condition where the system controller has detected an improper condition or state of the equipment. The existence of the fault will be indicated on the system controller until the fault is cleared by a specific action.

Fault Delimiter
Pertains to a system with a serial interface. A character, in the response command, which identifies the subsequent value as a fault identifier and which separates it from preceding values

Flow Volume
1) Rotary System: The flow magnitude, (and direction), relative to the pump size and due to the angular deflection of the Pump Module cylinder with respect to the "zero" point on the calibration scale of the specific Pump Module. 2) Linear System: The flow magnitude, (and direction), relative to the pump size and due to the selected controller settings.

Fluid Shear
The separation of the dispensed liquid from the liquid remaining in the dispense tip. Optimizing several factors, such as the dispense tip geometry and dispense rate, improves fluid shear and the repeatability of the dispense volume.

Fluid Slip
Commonly used to describe the migration of liquid around the internal moving parts of a pump. It is the volumetric difference between physical component displacement and liquid throughput of a pump system.

Fluid Slip Loss
Refers to the liquid which passes through the clearance space, (~.00005") between the piston and the cylinder wall. The clearance between the piston and cylinder wall must be optimized for the liquid being pumped in order to minimize the loss due to fluid slip.

Provides for washing the rear portion of the piston by a liquid passing at a rate of ~2 to 5 ml/min through a groove in the cylinder wall. The gland prevents the liquid being dispensed from accumulating at the rear of the piston, thereby greatly reducing the possibility of a seized pump.

Hall Effect
In a current-carrying semiconductor bar located in a magnetic field that is perpendicular to the direction of the current, the production of a voltage perpendicular to both the current and the magnetic field. This physical effect is used in position sensors.


  1. The relative resistance of a mineral to scratching, as measured by the Mohs' scale.
  2. The relative resistance of a metal to denting, scratching or bending.

Hardwired Signals
Electrical signals between two control devices connected with dedicated conductors.


  1. A point or device at which a transition between media, power levels or modes of operation is made.
  2. The hardware and signal specifications for linking two units of electronic equipment.

LED Indicators
Light Emitting Diodes. Utilized as system condition or mode indicators and warnings.


Linear Movement
Movement along a straight line.

Linear Rate
Rate of the linear component of a movement.

Load Mode
Linear controller mode used to load the pump cylinder when empty or when the volume is less than the next volume of liquid required to dispense or meter. The automatic load function can be set to Manual, Empty, or Every.

Load Rate
The pumping rate, of a linear system, during the load cycle in microliters per second, (ml/s). The same controller setting is used for loading and priming.

Mechanical Valving
Valve ports are opened and closed via mechanical actuation. This is in contrast to check valves which open and close as a result of fluid pressure/flow.

Meter Mode
Controller mode function used for continuous pumping of liquid. METER is very similar to PRIME. The difference between the two is PRIME gets the system setup for dispensing or metering of liquid and METER is used for constant flow, liquid metering.

Rotary Pumps, (B, C and D sizes); An optional micrometer scale assembly mounted to the Motor/Base Module. Used for position finding or fine adjustment and not for gross pump head movement.

Motor/Base Module
The module in a rotary system that drives the piston in the attached Pump Module. The Motor/Base Module produces a combined rotary and linear movement that synchronizes the liquid displacement and valving functions. The module consists of a motor, spindle, spindle sensor, base frame and adjusting mount for the Pump Module.

Multiplex System
The Multiplex system uses a single motor and two lead-screws to drive multiple three-piece pump modules. The motor and lead-screw combination drive the pistons in a linear motion to create displacement. Each Pump Module has an air driven rotary actuator to turn the valve towards the intake or discharge port.

Any unwanted disturbance within a dynamic electrical or mechanical system. This can include electrical, electromagnetic, or acoustical energy.

Operating Parameters

  1. All specified values utilized during system operation in order to achieve the desired performance of the system.
  2. The system controller values regarding volume, rate and direction, or Pump Module displacement setting, or controller settings for motion control devices incorporated with the system.

Optically Isolated Signal
Signals that are coupled using a device that connects signals from one electronic circuit to another by means of light. More correctly, the signals are electrically isolated and optically coupled between the two circuits.

Pump Module component. Part of the piston/cylinder set.

Actuated or operated by compressed air or other gas.

Openings in the Pump Module cylinder and housing allowing the flow of liquid through the Pump Module assembly during operation. Used for filling the pump liquid circuit, (inlet tubing, pump chamber, outlet tubing), at initial start-up. Also for eliminating air bubbles in the circuit.

Prime Rate
Motor speed during a prime operation. In a linear system, the prime rate and the load rate use the same setting. In a rotary system, the prime rate may be the same as the dispensing rate, or a separate setting may be used.

Cyclical fluctuations of liquid flow.

Pulse Damper or Pulse Suppressor
Mechanical device inserted into the outlet tubing of the liquid circuit to dampen liquid pulsations.

Pump Module
Liquid management system assembly consisting of the precision ceramic piston/cylinder set, protective housing, mounting hardware and fittings.

Pump Seized
An event whereby the ceramic piston and cylinder set become locked or "frozen" together.

Reference Cycle
In a linear system, an operational cycle during which the controller determines the absolute linear and rotary position of the linear actuator. After the power is turned on, or after a fault, a reference cycle must be completed before any other operation of the linear actuator can take place.

Rotary Movement
The motion, (rotation) of a part or device around an axis.

Rotary Series System
One of two major types of precision liquid dispensing or metering systems available from IVEK Corporation. The rotary system has a single mechanical coupling which translates the rotation of the motor into the combined linear (displacement) and rotary (valving) motions of the piston. The angular adjustment of the Pump Module determines the piston displacement for each dispense cycle. The controller does not have separate control of the linear and rotary motions of the piston. Liquid displacement is sinusoidal and corresponds to one rotation of the motor shaft (half is zero flow and half is 50% of sinusoid). The Digispense 3009 is a rotary system.

Rotary Valve
A device in which the rotation of a part performs the valving function.

Sanitary Pump
Pump Module option designed to conform to the cleansing standards of the US Food and Drug Administration.

Self Priming
A pump which requires no pre-wetting or pressurization procedure before being able to initiate liquid flow.

Specific Gravity
The ratio of the density of a fluid to the density of water. The specific gravity of a fluid must be considered when making gravimetric measurements (weighing) of the output of a volumetric pump.

Component in the Motor/Base Module of a rotary system, which couples the motor shaft to the piston. The spindle contains a spherical bearing which accepts the piston drive pin.

Stepper Motor
A digital device that converts electrical pulses into proportionate mechanical movement. Each revolution of the motor shaft is made in a series of discrete identical steps. The design of the motor usually provides for clockwise and(or) counterclockwise rotation.

A force that tends to produce rotation or twisting.

Torque Limited Drive
Motor function that will preclude piston breakage by causing the motor to stall in the event of a pump seizure.

Controller option displaying total motor turns or dispense triggers.

Selectively opening the liquid path between the pumping chamber and one of the liquid ports.

Valving Operation
Rotating the piston in a linear system to change the port communicating with the pumping chamber without displacing liquid.

Valving Speed
The rotational speed during valving in a linear system.

Variable Displacement
Capability of changing the volume of liquid moved by the piston for each stroke through either electrical or mechanical means.

The measure of a fluid's tendency to resist a shearing force. The viscosity of a fluid affects the degree to which it resists flow under an applied force. Viscosity can remain constant, increase, or decrease as shear rate (flow rate) increases. Absolute viscosity is generally measured in centipoise. Kinematic viscosity includes the influence of the specific gravity of the fluid and is generally measured in centistokes. Kinematic Viscosity X Specific Gravity = Absolute Viscosity

Wet Operations
Refers to the operation of the liquid management system. It is preferable to avoid running the pump dry. For extended periods, most application liquids will provide the necessary lubrication and cooling to prevent chirping, binding or seizure.

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Digifeed 2002 product sheet