Guralp Systems CMG-DM24S12AMS - Manual (Page 62)

CMG-DM24S12AMS Operator's guide
Although converting a sensor from horizontal to vertical
response involves compensating for the acceleration due to
gravity, you do not have to zero the sensor manually. The sensor
output offset adjustment is carried out electronically by
emulating the shift in mass position. You can then calibrate the
offset using a potentiometer within the unit, without any loss of
dynamic range.
62 Issue B