EGRET software is able to test and calibration Motion Lab Systems MA-400 and MA-300 EMG devices. It supports ONLY the x20 preamplifiers.  

The MA400 EMG system has a wide dynamic range with individual gain controls
provided for each EMG channel using one ten position rotary switch per EMG
channel. Therefore, the effective system gain is always fixed to discrete value and
the EMG output of the MA400 system is always calibrated so long as the individual
channel gain selections are known. As a result, the EMG output levels from the
MA400 can be directly related to the detected EMG level at the pre-amplifier inputs. When used with the standard x20 gain preamplifiers, the gain figures are accurate within 5% of the stated value for the system bandwidth as determined by the internal low pass filter and the optional band pass filter. Refer to MA-400 user manual for more details.

To perform the calibration procedure in EGRET software, go to Display Module and click on the icon on the upper right corner of the screen. A new menu will open on the right. Follow the procedure to perform the calibration. 

Bear in mind that for a correct calibration;

• The input range of the EMG Channels in the Analog Board must be set to ±5 volts. 
• The preamplifiers must be disconnected from Backpack unit.

Also keep in mind that the assumption of the calibration procedure is that the preamplifiers to be used are x20 gains.

The values provided in the calibration table provided by EGRET should be within 5% of those indicated on the Backpack Unit. If there is a substantial discrepancy between the two values, you may need to contact Motion Lab Systems for inspecting your device.