700B Headstage Calibration

700B Headstage Calibration

The steps below provide a quick check of the calibration of the MultiClamp 700B.  It is assumed that appropriate shielding (as described in “Test the Noise”, above) will be used during these tests.

1.  Connect an oscilloscope to the front panel PRIMARY or SCOPE Output BNC.

2.  Synchronize the oscilloscope by connecting to the rear panel SYNC OUTPUT BNC. Press the “Reset to Program Defaults” button in the MultiClamp 700B Commander to standardize the MultiClamp 700B.

50 G Range

1.  Press the “Options” button, choose the Gains tab, and select the 50 G feedback resistor in the Voltage Clamp pane.  Return to the main MultiClamp 700B Commander window.

2.  Plug the PATCH connector of the PATCH-1U model cell into the CV-7 headstage.

3.  Set Seal Test amplitude to 100 mV and frequency to 50 Hz, then check the box to make it active.

4.  Press Auto Cp Fast to remove the bulk of electrode capacitance transient.

5.  The resulting waveform should be square, except for an initial overshoot (possibly twice the size of the steady-state response) that settles to the baseline in about 1 to 2 ms.  The rise time to the peak of the overshoot should be about 50 μs.  The steady-state amplitude following the transient should be ~500 mVp-p (±50 mV).

5 G Range

1.  Change the feedback resistor to 5 G in the Options / Gains menu.

2.  Press Auto Cp Fast.

3.  The step response should be ~50 mVp-p (±5 mV).

500 M Range

1.  Press the “Reset to Program Defaults” button.  (By default, the 500 M

range is selected.)

2.  Check Seal Test and set the amplitude to 25 mV.

3.  Plug the CELL connector of the PATCH-1U model cell into the CV-7 headstage.

4.  Press the Auto Whole Cell button.

5.  Press Auto Cp Fast button.

6.  The step response should be ~25 mVp-p. 

50 M Range

1.  Change the feedback resistor to 50 M.

2.  Increase Output Gain to 10.

3.  Press Auto Whole Cell and Auto Cp Fast.

4.  The step response should be ~25 mVp-p.