How Programming Software Enhances Hotplate Magnet Stirrer Functionality

“Set and forget” features are welcomed by busy researchers operating a variety of equipment in the lab, among which are magnetic hotplate stirrers that may require frequent monitoring.  Here we will describe how programming software, exemplified by CAT “Shake and Stir,” helps enhance hotplate stirrer functionality.

We’ll cover

  • Where CAT’s Shake and Stir software is used
  • How it works
  • What researchers see on the Shake and Stir screen

But first, our traditional brief on hotplate magnetic stirrers.  If you are familiar with this equipment feel free to skip to the main points.

A Brief Introduction to Magnetic Hotplate Stirrers

Magnetic Hotplate stirrers incorporate a motor-powered rotating magnet in their base that causes a loose, coated bar magnet (called a flea) in beakers and flasks to rotate as well and provide the stirring action in liquids of low to moderate viscosity.

Models can accommodate beakers up to 10 liters in capacity.  Heat can be controlled in 1⁰C increments to 450⁰C.  Units are equipped with control panels allowing researchers to set stirring speed, time, temperature and other parameters.  CAT Scientific offers several models of magnetic hotplate stirrers.

Where  CAT Shake and Stir Software is Used

Once programmed, individual hotplate stirrers are capable of operating unattended for several hours.  If additional units are employed in the lab, or researchers are devoting attention to other tasks, monitoring hotplate stirrers can cause distractions or be overlooked.

This is where the Shake and Stir software earns its keep.

Device programming – that is programming the magnetic stirrer(s) – is simplified by using a computer mouse and cursor to set Shake and Stir software parameters.  Put  another way when installed on a PC, the software takes over the operation of magnetic stirrers following programming input by researchers.

How Shake and Stir Works

The computer screen shows a split view user interface – the left is for programming the device(s) and the right showing the status of the devices being monitored by Shake and Stir.   The system operates by manual or automatic control.  Once programming is set the operator can collapse the left screen leaving the device view screen visible to check on the processing status.

By clicking the “Manual Operation” tab the researcher inputs all relevant settings for the device. Depending on the device being controlled the software will then automatically set the parameter ranges, provide readings in ⁰C or ⁰F and enable or disable specific device features.

If an external Pt100 temperature probe is attached to the device it will be automatically detected and shown as “Pt100 probe.” If there is no probe the screen shows “hotplate.”  For information on this probe see our post on Why you Need a Magnetic Stirrer Temperature Probe.

Four standard settings – probe set (or plate set) temperature, motor speed in RPM, sample volume and ramp heating (if applicable) in degrees per hour – are provided in 3 profiles for different processes.

With the Pt100 probe attached the plate temperature limit can be set.  A safety delta setting will automatically shut the hotplate off if the temperature is exceeded. The motor continues stirring until the safety stir time is exceeded.

Once programming is completed researchers hit the start button to transfer the programmed data to the device to activate the magnetic stirrer and hotplate.  The “stop” button does just that.

By clicking on the “Automatic” tab researchers program the automation process. Depending on the detected device type, the program automatically sets the parameter ranges, sets the unit to Celsius or Fahrenheit (if available) and enables or disables specific device features.   As with the manual operation the unit detects and indicates if a Pt100 probe is attached.

Data can be collected by clicking the “auto record” button.  Program controls provide options for opening a saved program, a new program, and recording the new program.  As with the manual operation researchers must set parameters including the duration of the run, probe/hotplate temperature, motor RPM and if ramp heating is required.

Other tabs access the records screen and perform communications settings.

The Shake and Stir View Screen

The device view screen (see illustration) identifies the specific device being operated by model number.  It shows set and actual probe temperature (if a probe is present), the set plate limit and actual temperature, and the set and actual motor speed.  If a probe is not present the plate set and actual temperature are indicated. Also displayed is the volume of the sample container, the safety cutoff temperature, whether or not ramp heating is engaged and the elapsed time.

A record key can be used instead of the record tab to send information to archives, and a standby button can be used with devices that support that function.

Other features of the CAT Shake and Stir control system are available from CAT Scientific.  Contact us for more details or to request a copy of the Operating Manual.

Bob Wilcox

Bob Wilcox has represented CAT Scientific’s family of homogenizers, magnetic stirrers, liquid handling and related laboratory equipment since 2002 when Staufen, Germany-based CAT Ingenieurbüro M. Zipperer GMbH established operations in North America. Bob oversees CAT Scientific laboratory apparatus sales and service organization from the company’s headquarters in Paso Robles, CA. He also is in charge of the parent company’s line of JetCat jet turbines, turboprop, and helicopter power plants for hobbyists’ radio controlled fixed wing and helicopter model aircraft. -- Earlier in Bob’s career he was involved in visual and special effects as well as camera and electronics supervisory responsibilities for the motion picture and television industry.

Leave a Comment