Multichannel Systems STG4002 Manual - Manual (Page 99)

Troubleshooting
95
12.7
Internal Calibration Signals
The STG emits sometimes autonomous high frequency signals.
Cause:
During the first ten minutes after starting the STG, the device emits every minute high frequency
signals (small bursts) for internal offset calibration of the current outputs in a range of +/- 10 mV.
After warming up the STG, the calibration signals later will be delivered half-hourly.
The calibration is interrupted during stimulation.
High sensitive measuring equipments will monitor these calibration signals. Biological signals are
usually slower than the high frequency bursts and will not interfere with the calibration signals.
When monitoring the experimental signals with MC_Rack software, you do not see the calibration
signals, because MC_Rack automatically applies a 3 kHz low pass filter during data acquisition, and
a 10 kHz low pass filter during filter activities.
When using MC_Stimulus II Version 3.3 and higher it is possible to avoid the internal offset
calibration. Enable the command “Disable Autocalibration” in main menu “STG” and download
the command to the STG.