Multichannel Systems MEA2100-System Manual - Manual (Page 14)

MEA2100-System Manual
10
Hardware Settings for the MEA2100-System in the Data Source
When using the MEA2100-System, the “Hardware” tab of the MC_Rack software is modified.
Please see also chapter “Defining a Data Source”.
In the "Hardware" tab of the Data Source, the gain setting must be adjusted to ensure a correct
scaling of the data in MC_Rack. The gain is a fixed hardware property, while sampling frequency
and input voltage range of the data acquisition board can be selected according to the demands
of the experiment.
The appropriate “Amplifier Gain” factor of the MEA2100-System will automatically be entered.
Depending on the hardware revision the MEA2100-System the gain factor is 5, in older revisions
factor 2.
The ADCs (Analog Digital Converter) of the MEA2100 system have a resolution of 24 bit, the
MC_Rack software can record and display data with a resolution of 16 bit. To handle the complete
24 bit range, the input voltage range selection in the MC_Rack software can select a window of
16 bit out of these 24 bits, resulting in the following signal ranges:
+/- 812 μV; +/- 1727 μV, +/- 3545 μV; +/- 7090 μV;
+/- 14 mV; +/- 28 mV, +/- 57 mV; +/- 114 mV; +/- 227 mV
A smaller input range results in a better resolution in bits/μV, signals larger than the selected
range will be clipped. In summary, the procedure has exactly the same functionality as a software
selectable gain, even though, strictly speaking, it is not.
The “Sampling Frequency” should also be selected as low as possible, depending on the signals
you like to measure, to minimize data file size.
If several instances of MC_Rack are used to operate the MEA2100-System, for example with
a MEA2100-HS2x60 headstage or two MEA2100-HS120 headstages, each instance of MC_Rack
operates independently; you can define the “Input Voltage Range of Data Acquisition Board”
and the “Sampling Frequency” for each instance of MC_Rack individually.
Hardware Filter Settings
While the MEA2100-System in principle can measure DC signals, this is for most purposes
very impractical, as the baseline would constantly drift. Therefore the system is equipped with
software configured hardware filters. By default, a second order high pass filter with a cut off
frequency of 1 Hz is used to prevent a baseline drift. The upper cut off frequency is 3.3 kHz.
Additionally you can use the software filters of MC_Rack, if necessary.
Note: It is possible to change the settings of these filters without modification
of firmware or hardware. Please read chapter ”MEA2100 Configuration Software”.