Omega Speaker Systems PCI-DAS1002 manual Analog Connections, Single-Ended and Differential Inputs

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4.0 ANALOG CONNECTIONS

4.1 ANALOG INPUTS

Analog signal connection is one of the most challenging aspects of applying a data acquisition board. If you are an Analog Electrical Engineer then this section is not for you, but if you are like most PC data acquisition users, the best way to connect your analog inputs may not be obvious. Though complete coverage of this topic is well beyond the scope of this manual, the following section provides some explanations and helpful hints regarding these analog input connections. This section is designed to help you achieve the optimum performance from your PCI-DAS1000 series board.

Prior to jumping into actual connection schemes, you should have at least a basic understanding of Single-Ended/Differen- tial inputs and system grounding/isolation. If you are already comfortable with these concepts you may wish to skip to the next section (on wiring configurations).

4.1.1 Single-Ended and Differential Inputs

The PCI-DAS1000 provides either 8 differential or 16 single-ended input channels. The concepts of single-ended and differential inputs are discussed in the following section.

Single-Ended Inputs

A single-ended input measures the voltage between the input signal and ground. In this case, in single-ended mode the PCI-DAS1000 measures the voltage between the input channel and LLGND. The single-ended input configuration requires only one physical connection (wire) per channel and allows the PCI-DAS1000 to monitor more channels than the (2-wire) differential configuration using the same connector and onboard multiplexor. However, since the PCI-DAS1000 is measur- ing the input voltage relative to its own low level ground, single-ended inputs are more susceptible to both EMI (Electro Magnetic Interference) and any ground noise at the signal source. The following diagrams show the single-ended input configuration.

CH IN

LL GND

I/O

C onnector

+

In p ut

 

To A /D

A m p

 

 

 

-

Single-Ended Input

 

 

 

CH IN

+

 

 

~

 

 

 

 

 

 

V s

Vs + V g2 - V g1

Inp ut

 

To A /D

A m p

 

 

 

LL GN D

-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

g1

g 2

An y voltage differential betw een grounds g1 and g2 show s up as an error signal at the input am plifier

S in gle -ended input w ith C om m on M ode Voltage

5

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Contents Users Guide Table of Contents BADR0 BADR1 BADR2BADR3 BADR4Introduction Installation IntroductionRUN InstaCal DOS and/or WindowsConnector PIN Diagram Hardware ConnectionsSingle-Ended Inputs Analog ConnectionsSingle-Ended and Differential Inputs Differential Input Differential InputsSystem Grounds and Isolation Which system do you have?Large Common Mode Voltages Systems with Common Mode ground offset VoltagesSmall Common Mode Voltages PCI-DAS1000 and signal source already have isolated grounds Ground Category Input Configuration Our view    Board Board Programming & Software Applications SELF-CALIBRATION of the PCI-DAS1000 Analog InputsAnalog Outputs BADR0 BADR1Interrupt / ADC Fifo Register Region Function OperationsInte EoaieIntcl AdflclADC Channel MUX and Control Register BADR1 + CHL8-CHL1, CHH8-CHH1= ADC Done = ADC Busy EOCPacer Source ARM Trigger CONTROL/STATUS Register BADR1 +TS10 Fifo Mode Sample CTR C0SRCXtrig IndxgtCalibration Register BADR1 +DAC Channel Cal Function Cal SourceDacen Mode DAC CONTROL/STATUS Register BADR1 +DACnR10 DACnR1 DACnR0 Range LSB SizeBADR2 ADC Data Register BADR2 +ADC Fifo Clear Register BADR2 + MSB LSBBADR3 ADC Pacer Clock Data and Control RegistersBADR3 + Device Counter # FunctionADC 8254 Control Register Digital I/O Data and Control RegistersDIO Port a Data DIO Port B DataPort a Port C Port B Upper Lower OUT DIO Port C DataDIO Control Register Index and User Counter 4 Data and Control Registers 8254B Counter 1 Data User Counter #58254B Counter 2 Data User Counter #6 BADR3 + Ah8254B Control Register BADR3 + BhBADR4 1 DAC0 Data RegisterBADR4 + 2 DAC1 Data RegisterElectrical Specifications Analog Output Power consumption EnvironmentalEC Declaration of Conformity
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