User manual

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CHAPTER 14 – Additional Information about WinLTP
14.1 Using the Internal Gain on M- and X-Series National
Instruments Boards
In WinLTP 2.10 we have implemented the internal gain that is present in M- and X-series National
Instruments boards. The internal gains can be x2, x10 and x50 for the inexpensive boards like the PCI-
6221, PCIe-6321, USB-6341, USB 6341 BNC, PCI-6229, PCIe-6323, USB-6343, USB-6343 BNC and x1,
x5, x10, x20, x50 and x100 for the more expensive boards like the PCI-6251, PCI-6259, USB-6259 BNC,
PCIe-6351, PCIe-6353 and USB-6351 and USB-6353.
For voltage amplifiers with only x10 external gain (like the Axon AxoClamp-2B), this allows the data
acquisition board to supply the necessary additional gain rather than having to put in a second external
amplifier (Fig. 14.1).
Fig. 14.1. External and internal gain arrangements. A) Gain arrangement prior to WinLTP 2.10 has only
the ‘Gain’ is the total gain and is equal to the external gain, with the NI board internal gain equal to x1. So
if you have an external preamp with a x10 gain like the AxoCalmp-2B, you have to add an external
second amplifier (here at x10) to bring the total gain (eg ‘Gain’) in this example to to x100. B) In WinLTP
2.10 internal gain was added. So if you have an external preamp with a x10 gain like the AxoCalmp-2B,
you do not need to have an external second amplifier. Therefore setting the ‘External Gain’ to x10 and
the NI board ‘Internal Gain’ to x10 brings the ‘Total Gain’ to x100.