Can I calibrate my Hardy system without using test weights?

The best way to calibrate your Hardy system is by using C2® second generation equipment and C2® load cells. If you do not have C2® technology on your load cells or controller there is another way to calibrate your system without test weights by utilizing the data from your load cell certificate.

This answer applies to most of the Hardy instruments.

If you have the load cell certificate you can calibrate a weigh system using the HI2151/30WC and soft calibration without test weights.  The Soft cal function is available in the 2151/30, 2110 WI, 1746WS (with the WS100 software) and the 1771WS weigh scale software.  No other models have the soft cal function. 

If you have the load cell certificate and an accurate millivolt meter (two decimal points for the Mv scale) you can calibrate a weigh system using the other Hardy weight controllers. 

For our example, let's say your load cell certificate says 1,000 lb capacity at 2.0 Mv/V. That means a Hardy Process Solutions scale controller with 5 volts excitation will output 10mV at 1,000 lb. 1Mv equals 100 lbs of force applied. (Sense voltage X Millivolt per Volt rating = maximum millivolt output level at full capacity).  You must install sense lines and remove the sense jumpers to get an accurate sense voltage.

Hardy Advantage series load cell certificates are available online at certification tool. Enter the serial number of your load cell and print the certificate for reference.

If your Advantage series Load Cell Certificate is not found in our online database you can email your certificate request to hardysupport@hardysolutions.com

 Please include all information from the load cell label, especially the model, serial number, and the name of the original purchasing company.  Copies of the load cell certificates are kept in the original sales folder for three years.   We will do our best to find your load cell certificate, but cannot guarantee it will be found, especially if your load cell is over three years old.

Using your load cell certificate data you can establish the zero point and span points. Find the maximum weight/pressure required and use that as a target. Using a millivolt meter with two or more decimal point resolution, measure the load cell output across Signal Plus and Signal Minus with no or the minimum pressure on the load cell. This is your zero or cal low reference point.
Perform the cal low command to set gross zero.

You now have a zero reference and calculations for the millivolt reading at maximum capacity. Next, apply a constant pressure equaling your system target weight. Measure the millivolt signal level at the back of the weight controller's signal + and signal - terminals. For example you might read 4.9mv. With the zero = 0.1 and this at 4.9, the difference is 4.8mv.

In our example, 1,000 lb / 10mV = 100 lb/mV or the 4.8mv X 100 lb/mV = 480 lb of pressure, and enter this as the SPAN weight and do the Cal high/span command.

The Gross weight will now read 480 and when the pressure or weight is removed you should read 0. Pressure levels in a linear pressure system will provide a linear weight reading representing the pressure applied.