ADLINK Technology cPCI-9116 Guide de l'utilisateur télécharger pdf (Page 27)

Signal Connections • 17

User Common Mode (U_CMMD)

To measure ground-referenced signal sources, which are connected to the

same ground point, you can connect the signals in a User-Common-Mode

(U_CMMD) configuration. Fig 7 illustrates the connections. The signal local

ground reference is connected to the negative input of the instrumentation

Amplifier, and the common-mode ground potential to signal ground. The

instrumentation amplifier will now reject the 9116 series ground.

AIn

U_CMMD

n = 0, ...,63

Ground-

Referenced

Signal Source

Instrumentation

Amplifier

To A/D

Converter

Input Multipexer

Common-

mode noise &

Ground

potential

Figure 7: Ground-referenced source and User Common Mode connections

3.3 Digital I/O Connection

The 9116 series card provides 8 digital input and 8 digital output channels. The

digital I/O signals are fully TTL/DTL compatible. The details of the digital I/O

signal specification can be found in section 1.3.

Digital Input(DI)

74LS244

From TTL Signal

To TTL Devices

Digital Output(DO)

Digital GND(DGND)

74LS244

Figure 8: Digital I/O Connection

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ADLINK Technology cPCI-9116 Guide de l'utilisateur Page 27