Will my Hardy Instrument work with a Load Cell rated at 10 volt excitation?

Load cells do not require a specific excitation voltage. A load cell or strain gauge is based on the wheatstone bridge theory and only changes the millivolt signal for an applied load. A higher range of excitation voltage going to the load cell is specified on the load cell certificate.  Load cell manufacturers use 5, 10, 15, 24 and 48 volts for excitation. The output of all load cells are rated in milli volt per volt (mV/V). This way the load cell end user can multiple the mV/V rating by the excitation voltage and find the signal output at maximum loading.

As an example, a weight controller may provide 5 volts excitation with intrinsic barriers. The barriers reduce the excitation voltage level to approximately half, or 3 v dc. The Hardy weight controllers perform without any problem with an actual 5 or 3 volt excitation.

Load cells are normally tested at 10 volts excitation, but have their sensitivity listed as millivolts per volt. To convert from millivolt to millivolt per volt for a given load cell output, measure the voltage across the +/- SIG wires. Then measure the voltage across the +/- SEN wires. Divide the value measured on SIG by the SEN value to get the millivolt/volt level. This mV/V system makes the load cell easily convertible to the excitation voltage your system is using.

For example, if you have 4.8 volts on +/- SEN and you have 0.2 millivolts on +/- SIG, then:

0.2/4.8 = 0.041 millivolts per volt.

Any advantage of using a 10 vdc excitation voltage has been nullified by the advancement of technology. Hardy products have been utilizing a 5vdc excitation voltage since 1999.  This has been achieved by using superior design and quality A/D converters in our controllers.  We are processing data to the 0.1 micro-volt level and have the ability to achieve the rated load cell accuracy, even with intrinsic safety barriers that can reduce the excitation voltage down to 1.8vdc.

Certification testing is traditionally completed using a 10vdc power source. That is why you see there are maximum voltage ratings, but no low voltage limits.