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Control System for Gel Casting Machine for Gel Electrophoresis Cartridges


Syringe Pumps and Motor Controllers
Syringe Pumps and Motor Controllers

The Challenge

A company that designs and manufactures medical and scientific equipment approached us with the need for a system to automate the casting of their gel electrophoresis cartridges.


The Solution

Using syringe pumps, precision motor controllers, NI CompactRIO hardware, and a LabVIEW motor control architecture, we built the customer a set of multi-channel pumps to automate the casting of their gel electrophoresis cartridges.


The Story//The Cyth Process

Gel electrophoresis cartridge
Diagram of a gel electrophoresis cartridge

Figure 1. A gel electrophoresis cartridge is used with a power source to provide a medium in which DNA molecules are excited by a charge and will sort themselves based on size. (Image Credit: Khan Academy)


  • Gel electrophoresis is a technique used to separate DNA fragments based on their size. It involves running a current through a gel medium that contains the DNA molecules of interest. Based on their size the DNA fragments will travel different distances through the gel sorting themselves.

Multiple sets of multi-channel Kloehn syringe pumps
Our engineering team builds multiple sets of multi-channel Kloehn syringe pumps.

Figure 2. Our engineering team builds multiple sets of multi-channel Kloehn syringe pumps required to dispense gel into gel electrophoresis cartridges.


  • Our customer required the casting of a gel mixture into their manufactured cartridges to be automated.

  • Their proprietary gel mixture required a measured amount of 5 liquid solvents to be dispensed.

  • Our engineering team programmed a LabVIEW user interface that allowed a user to manually set the measurements they required for the 5 solvent mixture.

  • The Kloehn syringe pumps were controlled using stepper motors and the motor encoder communicated using Modbus TCP. Our LabVIEW motor control algorithms would translate the user-defined pump output to a cycle amount for the pump encoder. This would dispense the measured amount of gel required for one cartridge.


 5 multi-channel Kloehn syringe pumps
Diagram of plastic cartridges being cast with gel on a conveyor.

Figure 3. Top: The 5 multi-channel Kloehn syringe pumps required to dispense a solvent mixture.

Bottom: Plastic cartridges on a moving conveyor, being cast with gel by the syringe pumps.


Multichannel syringe pump system was controlled using a LabVIEW
LabVIEW user interface used to control the mutli-channel pump.

Figure 4. The multichannel syringe pump system was controlled using a LabVIEW user interface that allowed a user to set the desired measurements of each pump.


System Order of Operations:

  1. An operator manually turns on the conveyor.

  2. An operator uses the LabVIEW UI to either select a preset or to manually enter the required measurements of each of the 5 solvents required to make the customer’s gel.

  3. The cartridges are systematically released by motors onto the conveyor holder slots.

  4. As the cartridges move left to right their position is monitored using Sick proximity sensors.

  5. When a cartridge is registered as in position the multi-channel pumps send a control command via the encoder to the stepper motors.

  6. The stepper motors dispense and cast the solvents via the syringe pumps into the cartridge.

  7. The stepper motor cycles to refill the syringe with liquid solvent for the next cartridge.

  8. Steps 5 through 8 repeat.


Custom-built aluminum frame and fiberglass side housing
Custom-built fixture featuring an aluminum frame and fiberglass side housing.

Figure 5. A custom-built aluminum frame and fiberglass side housing to hold the multi-channel pumps.



Technical Specifications


30 x Kloehn Pump

30 x Kloehn Syringes

6 x Pump Manifold

6 x Multichannel Pump Custom Housing Fixture

1 x Fuse-10Amp Time Delay

1 x Power Receptacle

20 x DIN Rail Jumper Terminals








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