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Figure 7. Connecting to the DIO Channels

NI PCIe-7846

Power

FPGA

Connection

Accessory

DIO0

DIO1

DIO14

DIO15

Connecter 0 (MIO)

1

Connection

Accessory

DIO0

DIO1

DIO30

DIO31

Connecter 1 (DIO)

2

3

1. Low-speed signal frequencies up to 10 MHz with logic levels configured as 1.2 V, 1.5 V, 1.8 V, 2.5 V, or

3.3 V.

2. High-speed signal frequencies up to 80 MHz with logic levels configured as 1.2 V, 1.5 V, 1.8 V, 2.5 V, or

3.3 V.

3. LED

The DIO channels have overvoltage and undervoltage protection as well as over current
protection. Refer to the device specifications on 

ni.com/manuals

 for more information about

the maximum voltage and current.

When the system powers on, the DIO channels are set as input low with pull-down resistors.
To set another power-on state, you can configure the NI PCIe-7846 to load a VI when the
system powers on. The VI can then set the DIO lines to any power-on state.

All the high-speed DIO channels on Connector 1 are routed with a 50 Ω characteristic trace
impedance. Route all external circuitry with a similar impedance to ensure best signal quality.
NI recommends performing signal integrity measurements to test the affect of signal routing
with the cable and connection accessory for your application.

Field Wiring Considerations

Environmental noise can seriously affect the measurement accuracy of the device if you do not
take proper care when running signal wire between signal sources and the device. The
following recommendations mainly apply to AI signal routing to the device, as well as signal
routing in general.

6

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ni.com

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NI PCIe-7846 User Manual

Summary of Contents for NI R Series

Page 1: ...l Instruments PCIe 7846R Manual Get Pricing Availability at ApexWaves com Call Today 1 800 915 6216 Email sales apexwaves com https www apexwaves com modular systems national instruments r series PCIe...

Page 2: ...dware Overview The following high level block diagram represents the PCIe 7846 Figure 1 PCIe 7846 Block Diagram NI ASIC FPGA NI PCIe 7846 DIO Data Address Control AO AO x8 ADC AI AI x8 INA DIO x16 DIO...

Page 3: ...I1 AIGND0 AI0 5V DGND DGND DGND DGND DGND DGND DGND DGND DIO8 DIO10 DIO12 DIO14 AOGND7 AOGND6 AOGND5 AOGND4 AOGND3 AOGND2 AOGND1 AOGND0 NC AI7 AIGND7 AI6 AI5 AIGND5 AI4 AI3 AIGND3 AI2 AI1 AIGND1 AI0 6...

Page 4: ...e information Analog Input The PCIe 7846 provides connections for eight AI channels Each channel has an AI pin AI pin and AIGND pin to which you can connect both single ended or differential voltage s...

Page 5: ...the positive voltage signal to the AI and the negative voltage signal to AI To connect grounded differential signals to the PCIe 7846 you must also connect the signal reference to AI GND Figure 4 Con...

Page 6: ...nect a load Figure 6 Connecting a Load NI PCIe 7846 Connection Accessory AOGND LOAD AO DAC Digital I O The NI PCIe 7846 provides connections for 48 digital input output DIO channels Connector 0 contai...

Page 7: ...ut low with pull down resistors To set another power on state you can configure the NI PCIe 7846 to load a VI when the system powers on The VI can then set the DIO lines to any power on state All the...

Page 8: ...through conduits that also contain power lines Protect signal lines from magnetic fields caused by electric motors welding equipment breakers or transformers by running them through special metal con...

Page 9: ...ich provide up to date contact information Information is subject to change without notice Refer to the NI Trademarks and Logo Guidelines at ni com trademarks for information on NI trademarks Other pr...

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