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National Instruments NI 6115, NI 6120 AIGATE Signal, SISOURCE Signal

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Chapter 4 Connecting Signals

© National Instruments Corporation 4-27 NI 6115/6120 User Manual

The ADC switches to hold mode within 20ns of the selected edge. This

hold-mode delay time is a function of temperature and does not vary from

one conversion to the next.

The sample interval counter on the NI6115/6120 device normally

generates CONVERT* unless you select some external source. The counter

is started by the STARTSCAN signal and continues to count down and

reload itself until the scan is finished. It then reloads itself in preparation for

the next STARTSCAN pulse.

A/D conversions generated by either an internal or external CONVERT*

signal are inhibited unless they occur within a DAQ sequence. Scans

occurring within a DAQ sequence may be gated by either the hardware

signal AIGATE or the software command register gate.

AIGATE Signal

Any PFI pin can receive as an input the AIGATE signal, which is not

available as an output on the I/O connector. The AIGATE signal can mask

off scans in a DAQ sequence. You can configure the PFI pin you select as

the source for AIGATE in level-detection mode. You can configure the

polarity selection for the PFI pin for either active high or active low.

In the level-detection mode if AIGATE is active, the STARTSCAN signal

is masked off and no scans can occur.

AIGATE can neither stop a scan in progress nor continue a previously

gated-off scan. Once a scan has started, AIGATE does not gate off

conversions until the beginning of the next scan and, conversely, if

conversions are being gated off, AIGATE does not gate them back on until

the beginning of the next scan.

SISOURCE Signal

Any PFI pin can receive as an input the SISOURCE signal, which is not

available as an output on the I/O connector. The onboard scan interval

counter (SI) uses SISOURCE as a clock to time the generation of the

STARTSCAN signal. You must configure the PFI pin you select as the

source for SISOURCE in the level-detection mode. You can configure the

polarity selection for the PFI pin for either active high or active low.

The maximum allowed frequency is 20 MHz, with a minimum pulse width

of 23 ns high or low. There is no minimum frequency limitati on.

Contents

Main Page Important Information Warranty Copyright Trademarks Patents Compliance FCC/Canada Radio Frequency Interference Compliance Determining FCC Class FCC/DOC Warnings Class A Compliance to EU Directives Contents Chapter 4 Connecting Signals Page About This Manual Conventions National Instruments Documentation Related Documentation Introduction About the NI 6115/6120 Using PXI with CompactPCI What You Need to Get Started Software Programming Choices NI-DAQ National Instruments ADE Software Optional Equipment Custom Cabling Unpacking Safety Information Page Page Installing and Configuring the NI 6115/6120 Installing the Software Installing the Hardware Page Configuring the Device National Instruments Corporation 3-1 NI 6115/6120 User Manual Hardware Overview DAQ - STC RTSI Bus Figure 3-1. NI 6115 Block Diagram Analog Input The following sections describe in detail each AI category. Input Mode Note The inputs are differential only in the sense that the ground loops are broken. I/O Connector Input Polarity and Input Range Considerations for Selecting Input Ranges Input Coupling Analog Output Analog Trigger Figure 3-3. Analog Trigger Block Diagram for the NI 6115/6120 Figure 3-4. Below-Low-Level Analog Triggering Mode Page Antialiasing Filters Phase-Locked Loop Circuit Correlated Digital I/O Timing Signal Routing Page Programmable Function Inputs Device and RTSI Clocks RTSI Triggers Page Figure 3-13. PXI RTSI Bus Signal Connections Connecting Signals I/O Connector Figure 4-1. I/O Connector Pin Assignment for the NI 6115/6120 I/O Connector Signal Descriptions Table 4-2. Signal Descriptions for I/O Connector Pins Table 4-2. Signal Descriptions for I/O Connector Pins (Continued) Table 4-3. Analog I/O Signal Summary for the NI 6115 Table 4-2. Signal Descriptions for I/O Connector Pins (Continued) Table 4-4. Analog I/O Summary for the NI 6120 Table 4-5. Digital I/O Signal Summary Types of Signal Sources Floating Signal Sources Table 4-5. Digital I/O Signal Summary (Continued) Ground-Referenced Signal Sources Connecting Analog Input Signals Connections for Ground-Referenced Signal Sources * Figure 4-2. Pseudodifferential Input Connections on the NI 6115 forGro und-Referenced Signals Figure 4-3. Pseudodifferential Input Connections on the NI 6120 forGro und-Referenced Signals Connections for Nonreferenced or Floating Signal Sources * Figure 4-4. Differential Input Connections on the NI 6115 for Nonreferenced Signals Common-Mode Signal Rejection Considerations Working Voltage Range Connecting Analog Output Signals Connecting Digital I/O Signals Correlating DIO Signal Connections Page Power Connections Connecting Timing Signals Page Programmable Function Input Connections DAQ Timing Connections TRIG1 Signal TRIG2 Signal Page STARTSCAN Signal Page CONVERT* Signal AIGATE Signal SISOURCE Signal SCANCLK Signal EXTSTROBE* Signal Waveform Generation Timing Connections WFTRIG Signal UPDATE* Signal UISOURCE Signal General-Purpose Timing Signal Connections GPCTR0_SOURCE Signal GPCTR0_GATE Signal GPCTR0_OUT Signal GPCTR0_UP_DOWN Signal GPCTR1_SOURCE Signal GPCTR1_GATE Signal GPCTR1_OUT Signal Figure4-34 shows the timing requirements for GPCTR1_OUT. Figure 4-35. GPCTR1_OUT Signal Timing Figure 4-36. GPCTR Timing Summary GPCTR1_UP_DOWN Signal FREQ_OUT Signal Field Wiring Considerations Calibration Loading Stored Calibration Constants Self-Calibration External Calibration Page A Specifications Analog Input Input Characteristics DC Transfer Characteristics Table A-1. NI 6115 Analog Input DC Accuracy Information Table A-2. NI 6120 Analog Input DC Accuracy Information Dynamic Characteristics Table A-4. NI6120 Analog Input Dynamic Charac teristics Figure A-1. NI 6115 Total Harmonic Distortion Plus Noise (THD+N) Figure A-2. NI 6120 Total Harmonic Distortion Plus Noise (THD+N) Figure A-3. NI6115 High-Voltage THD + N Figure A-4. NI 6120 High-Voltage THD+ N Figure A-5. NI 6115 THD + N with Filters Stability Analog Output Output Characteristics DC Transfer Characteristics Voltage Output Dynamic Characteristics Stability Digital I/O Timing I/O Triggers Analog Trigger Page Safety Maximum Working Voltage Electromagnetic Compatibility B Common Questions General Information Installing and Configuring the Device Analog Input and Output Page Timing and Digital I/O Page C Technical Support and Professional Services Glossary Numbers/Symbols A B C D E F G H I K L M N O P R S T U V W Index Numerics A B C D E F G H I K L M N O P Q R S Page T U V W