Omega Engineering manual Self-Calibration of the PCI-DAS1200

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6.0 Self-Calibration of the PCI-DAS1200

The PCI-DAS1200 is shipped fully-calibrated from the factory with cal coefficients stored in nvRAM. When using Universal Library at run time, these calibration factors are loaded into system memory and are automatically retrieved each time a different DAC/ADC range is specified. The user has the option to recalibrate with respect to the factory-measured voltage standards at any time by simply selecting the "Calibrate" option in InstaCal. Full calibration typically requires less than two minutes and requires no user intervention.

6.1 CALIBRATION CONFIGURATION

The PCI-DAS1200 provides self-calibration of the analog source and measurment systems thereby eliminating the need for external equipment and user adjustments. All adjustments are made via 8-bit calibration DACs or 7-bit digital potentiometers referenced to an on-board factory calibrated standard. Calibration factors are stored on the serial nvRAM..

A variety of methods are used to calibrate the different elements on the board. The analog front-end has several knobs to turn. Offset calibration is performed in the instrumentation amplifier gain stage. Front-end gain adjustment is performed via a variable attenuator/gain stage.

The analog output circuits are calibrated for both gain and offset. Offset adjustments for the analog output are made in the output buffer section. The tuning range of this adjustment allows for max DAC and output buffer offsets. Gain calibration of the analog outputs are performed via DAC reference adjustments.

Figure 1 below is a block diagram of the analog front-end calibration system:

Cal

RefPGA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Offset Adj

 

 

 

 

8

 

 

 

 

 

O f f s e t

 

 

 

 

 

T r i m D a c

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Coarse)

 

 

 

 

 

 

 

 

T r i m D a c

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Fi ne)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Variable Gain

ADC

7

Digital Offset Pot

Figure 1

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Contents Users Guide Table of Contents Table of Contents ORFN3&,$LDJUDP6 %ORFN$LDJUDP6-5 Installation Windows 95, 98 & NTUsing InstaCal DOS AND/OR Windows Testing the Installation Connector PIN Diagram Hardware ConnectionsAnalog Connections Differential Input System Grounds and Isolation Which system do you have?Systems with Common Mode ground offset Voltages Systems with Common GroundsWiring Configurations Small Common Mode VoltagesLarge Common Mode Voltages PCI-DAS1200 and signal source already have isolated grounds  Common Ground / Single-Ended InputsCommon Mode Voltage +/-10V / Single-Ended Inputs Common Mode Voltage +/-10VBoard Programming & Applications Programming LanguagesSelf-Calibration of the PCI-DAS1200 Alo g O u t BADR0 BADR1Interrupt / ADC Fifo Register Region Function OperationsInte EoaieEoacl IntclADC Channel MUX and Control Register Input Range Input Gain Measurement Resolution EOCTrigger CONTROL/STATUS Register Pacer SourceTS10 TgenFifo Mode Sample CTR ARMC0SRC XtrigCal Source Calibration RegisterDAC Channel Cal Function Dacen Mode CalenSDI DACnR10BADR2 ADC Data RegisterBADR2 + ADC Fifo Clear RegisterBADR3 ADC Pacer Clock Data and Control Registers8254A Counter 0 Data ADC Post Trigger Conversion Counter BADR3 +8254A Counter 2 Data ADC Pacer Divider Upper Base +ADC 8254 Control Register Digital I/O Data and Control RegistersDIO Control Register DIO Port B DataDIO Port C Data Index and User Counter Data and Control Registers 8254B Counter DATA-ADCPRE-TRIGGER Index Counter Or User8254B Counter 1 Data User Counter #5 8254B Counter 2 Data User Counter #6BADR3 + Ah 8254B Control Register2 DAC1 Data Register BADR41 DAC0 Data Register Electrical Specifications Analog Input SectionAnalog Output Parallel Digital Input / OutputCounter Section 82C54AEnvironmental Other SpecificationsPower consumption For Your Notes EC Declaration of Conformity
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