What is the sensitivity of my weight controller?

What is the sensitivity of my weight controller?

Weight controllers are not measured by sensitivity like load cells. When you ask "what is the sensitivity", we think you are really asking how accurate the controller is, or maybe what is the smallest weight increment a controller can read.  

Weight controllers are measured by update rates, internal counts, and/or linearity.  Some manufactures give an overall accuracy for the controllers, but this controller accuracy rating cannot be associated to a weighing system accuracy or load cell accuracy.  The amount of error in a weight controller compared to the load cells and mechanical installation is very insignificant. 

System accuracy is determined by a combination of mechanical and electrical noise.  No accuracy figures are stated for Hardy Process Solutions weight controllers as we do not know anything about your electrical system, the mechanical aspects of your weighing system, or how much electrical noise is present in your facility.

If you are asking for the minimum weight reading, most Hardy controller minimum is established at 0.1 micro volt increments.  This alone does not mean anything as to weight readings, but 0.1 micro volts is the minimum signal reading incrementing from the load cell.  The problem is there are varying background noise levels in the work environment and a standard level of noise is typically 1.5 to 3 micro volts, which is many times the weight controllers minimum level.  We use  >15 increments for filtering to determine the best reading possible.  Also, a typical load cell outputs a 0-15,000 micro volts and gives a ratio of signal to noise of 1 part in 10,000.  This is considered your minimum repeatable and stable weight reading. Use your load cell capacity and this 1:10,000 ratio to determine what your stable and repeatable weight reading minimum will be.

The general guidelines for determining a system accuracy is to have a good installation and selecting the correct load cell capacity to fit the application.

Your application will also determine the accuracy of a scale system. A fill and dump-all application has the highest accuracy and conforms to the load cells Non-linearity specification number. A fill and then batch (dose) out smaller amounts uses the Hysteresis plus the Non-linearity specification number for a combined error.

The non-linearity and Hysteresis specifications for your Hardy Load Sensor is located on the load cell data sheet.