multifunction-rio-user-manual.pdf - 第51页

© National Instruments Corporation A-1 Mult ifunction Reconfigurable I/O User Manual A Connecting I/O Signals This appendix describes how to make input and output signal connections to the NI 78 xx I/O connectors. Figure…

Chapter 3 Calibration (NI 783x/784x/785x Only)

R Series Multifunction RIO User Manual 3-2 ni.com

drifts, particularly those due to changes in temperature. During the

self-calibration process, the AI and AO channels are compared to the

device onboard voltage reference. The offset and gain errors in the analog

circuitry are calibrated out by adjusting the CalDACs to minimize these

errors.

Note The NI 78xx Calibration Utility does not support NI 781x devices.

If you have NI-RIO installed, you can find the self-calibration utility at

Start»All Programs»National Instruments»NI-RIO»Calibrate 78xx

Device. Device is the PXI-783x/784x/785x or PCI-783x device.

Immediately after self-calibration, the only significant residual calibration

error is gain error due to time and temperature drift of the onboard voltage

reference. You can minimize gain errors by performing an external

calibration. If you are primarily taking relative measurements, then you can

ignore a small amount of gain error and self-calibration is sufficient.

The Flash memory on the NI 783x/784x/785x stores the results

of a self-calibration so the CalDACs automatically load with the newly

calculated calibration constants the next time the device is powered on.

External Calibration

An external calibration refers to calibrating your device with a known

external reference rather than relying on the onboard reference. The

NI 783x/784x/785x has an onboard calibration reference to ensure

the accuracy of self-calibration. The reference voltage is measured at the

factory and stored in the Flash memory for subsequent self-calibrations.

Externally calibrate the device annually or more often if you use it at

extreme temperatures.

During the external calibration process, the onboard reference value is

re-calculated. This compensates for any time or temperature drift-related

errors in the onboard reference that might have occurred since the last

calibration. You can save the results of the external calibration process to

Flash memory so that the NI 783x/784x/785x loads the new calibration

constants the next time it is powered on. The device uses the newly

measured onboard reference level for subsequent self-calibrations.

To externally calibrate your device, use an external reference several times

more accurate than the device itself. For more information on externally

calibrating your device, refer to the NI 783xR/784xR/785xR Calibration

Procedure for NI-RIO, found on

ni.com/docs.

Connecting I/O Signals

This appendix describes how to make input and output signal connections

to the NI 78xx I/O connectors.

Figure A-1 shows the I/O connector pin assignments and locations for

PCI-7811/7813 and PXI-7811/7813.

Figure A-2 shows the I/O connector pin assignments and locations

for PCI-7830/7831/7833, PCIe-7841/7842/7851/7852, and the

PXI-7830/7831/7833/7841/7842/7851/7852/

7853/7854.

Note The PXI-7830 and PCI-7830 do not have Connector 2 (RDIO).

Appendix A Connecting I/O Signals

Multifunction Reconfigurable I/O User Manual A-2 ni.com

Figure A-1. NI 781x Connector Pin Assignments and Locations

DGND

+5V

DIO28

DIO31

DIO33

DIO35

DIO37

DIO39

DIO0

DIO2

DIO3

DIO5

DIO6

DIO7

DIO8

DIO1

DIO4

DIO9

DIO10

DIO11

DIO12

DIO13

DIO14

DIO15

DIO16

DIO17

DIO18

DIO19

DIO20

DIO21

DIO22

DIO23

DIO24

DIO25

DIO26

DIO27

DIO29

DIO30

DIO32

DIO34

DIO36

DIO38

35 1

36 2

37 3

38 4

39 5

40 6

41 7

42 8

43 9

44 10

45 11

46 12

47 13

48 14

49 15

50 16

51 17

52 18

53 19

54 20

55 21

56 22

57 23

58 24

59 25

60 26

61 27

62 28

63 29

64 30

65 31

66 32

67 33

68 34

CONNECTOR 1

(RDIO)

TERMINAL 34

TERMINAL 68

TERMINAL 35

TERMINAL 1

TERMINAL 35

TERMINAL 1

TERMINAL 34

TERMINAL 68

TERMINAL 34

TERMINAL 68

TERMINAL 35

TERMINAL 1

CONNECTOR 0

(RDIO)

CONNECTOR 2

(RDIO)

TERMINAL 35

TERMINAL 1

TERMINAL 34

TERMINAL 68

CONNECTOR 3

(RDIO)