The resolution is defined by the noise amplitude of the measurement signal.
The noise amplitude is calculated e.g. as RMS mean value, or as peak value between maximum and minimum measured value or in decibels.
For simple comparability, we use the maximum noise amplitude for ME measurement systems. This peak value is determined over 100 measured values or over a time interval of 1s (from a set data frequency of 100Hz). As soon as one of the two conditions is reached, the noise amplitude is displayed.
The GSVmulti software provides a function for displaying the noise amplitude. This function is very useful, for example, to test the quality of the cabling and to eliminate possible sources of error at the beginning of a measurement.
In order to avoid small numbers, e.g. 20 nV / V or -90dB, we indicate how many times the noise amplitude is included in the positive measuring range: So many "steps" could be just read with the eye e.g. at an oscilloscope.
The measuring range is 2 mV/V or 3.5 mV/V, depending on the measuring amplifier.
This results in numerical values of the order of 1,000 to 100,000.
As a measurement condition, we select 1m connection cable, shielded, connected to a ME145 calibrator.
The digital noise of the A/D converter (1/32767 * 2 mV/V) is not responsible for the noise, but the quality of the operational amplifiers, the analog and digital filters employed, and, of course, external influences, e.g. interferences of e.g. frequency converters, alternating voltages, etc.
As a rule of thumb, at a data frequency of 10Hz, one should achieve a resolution of 5,000 to 10,000 parts in strain gauge technology using a strain gauge full bridge.
At 10 times the data frequency, the noise amplitude increases by 3.2 times (root of 10).
With the GSV-8 product, ME measuring systems achieve one of the highest resolutions in the field of commercially available strain gauge amplifiers.
GSV-6BT-6: The GSV-6BT is configured for 6 input channels. The larger data volume results in a maximum data frequency of 600Hz with 4 bytes per measured value.
GSV-6BT-1: The GSV-6BT is configured for 1 input channel. The maximum adjustable data frequency is 2kHz. The noise amplitude is slightly lower since a higher internal sampling frequency can be applied to the one measurement channel and thus improved digital filtering is achieved compared to the 6-channel configuration.
GSV-6BT-1s: The shield was additionally placed on the metallic housing of the calibrator ME145. The 2-byte protocol has been activated. This allows a data frequency of up to 3kHz to be achieved.