National Instruments Data Acquisition Device NI USB-621x - Manual (Page 131)

© National Instruments Corporation 9-1 NI USB-621x User Manual
9
Isolation and Digital Isolators on
USB-6215/6216/6218 Devices
USB-6215/6216/6218 devices are isolated data acquisition devices. The
analog input, analog output, counters, PFI/static DI, and PFI/static DO
circuitry
1 , and digital routing and clock generation are referenced to an
isolated ground, as shown in Figure 9-1.
Figure 9-1. USB-6215/6216/6218 Block Diagram
The bus interface circuitry is referenced to a non-isolated ground.
The following table lists the ground symbols.
1 USB-6216 devices have PFI/static DIO circuitry.
Ground Type Symbol
Isolated Ground
Non-Isolated Ground
Analog Output
Digital I/O
Analog Input
Counters
PFI
Digital
Routing
and Clock
Generation
Bus
Interface
Bus
I/O Connector
Digital
Isolators
Isolation
Barrier