Definition of load cell specification terms
Accuracy - Normally quoted as either a percentage of full scale output or a percentage of the applied
load. The accuracy figure is the combined error caused by non linearity, repeatability and hysteresis
error values in the load cell.
Rated Capacity - The maximum load over which the load cell which operate within its specifications.
Compensated temperature range - the range of temperatures over which the output from the cell is
compensated. If used outside this range the output cannot be guaranteed to follow the specifications.
Environmental protection - IP rating against moisture and dust e.g. IP65
Excitation - the voltage applied to the Ex+ and Ex- wires, normally quoted as minimum and maximum
values e.g. 5 to 15VDC or as a recommended value and maximum value.
Hysteresis -When a load cell is taken from zero to full load and back to zero the mV output for a given
load value will be slightly different when the load is rising to when the load is falling. The maximum
difference is used to calculate the hysteresis. Normally quoted as a percentage of full load.
Input resistance - the resistance measured across S+ and S- with load cell disconnected and no load.
Insulation resistance - Normally measured at 50VDC this is the minimum resistance between the
metal body of the load cell and any of its electrical connections.
Mechanical failure - the load at which the cell is likely to fail mechanically i.e. break or deform.
Rated output - the nominal mV/V output of the load cell.
Output resistance - the nominal resistance measured between Ex+ and Ex- with load cell
disconnected and no load.
Repeatability - ameasure of the ability of the load cell to repeatedly give the same output for the same
load under the same conditions. The error is normally quoted as a percentage of full load.
Safe load - the amount by which the capacity of the cell can be exceeded e.g. 125% of capacity.
Temperature effect on span - usually quoted as a percentage of full scale this is the change in output
at full load due to temperature changes. e.g. 0.01%/10°C means a change of up to 0.01% of full load
output per temperature change of 10 degrees C.
Temperature effect on zero - as above but measured at zero load.
Zero balance - the output of the load cell at no load, normally quoted as a percentage of full load. Also
know as zero offset.
Zero return (creep) - the difference between themVoutput at zero before a load is applied and themV
output at zero when returning from being loaded (after being given time to stabilise). Normally quoted
as a percentage of full load over a time period e.g. 0.03% (30mins).