National Instruments NI 6602 User Manual

Also see for NI 6601: User manual Manual User manual User manual User manual

National Instruments NI 6602 User Manual Manual pdf 39 page image

Chapter 3 Signal ConnectionsNI 660x User Manual 3-16 ni.comReal-Time System Integration BusTIO devices use the National Instruments Real-Time System Integration(RTSI) bus to easily synchronize several measurement functions to acommon trigger or timing event. In a PCI system, the RTSI bus consists ofthe RTSI bus interface and a ribbon cable. The bus can route timing andtrigger signals between several functions on as many as five DAQ devicesin the computer. In a PXI system, the RTSI bus consists of the RTSI businterface and the PXI trigger signals on the PXI backplane. This bus canroute timing and trigger signals between several functions on as many asseven DAQ devices in the system. For a RTSI connector pinout, go toni.com/info and enter rtsipin.RTSI TriggersTIO devices require a frequency timebase for its operation. This frequencytimebase must come from the onboard crystal oscillator and is requiredeven if the device is receiving a MasterTimebase signal from the RTSItrigger bus. Any TIO device can drive its 20MHzTimebase signal onto theRTSI Trigger 7 pin. Although some TIO devices have a 80MHzTimebase(such as the NI 6602), the RTSI bus cannot carry the 80MHzTimebasesignal for bandwidth reasons. By default, TIO devices do not drive theRTSI Trigger 7 bus clock line.Figure 3-8 shows the RTSI signal connection scheme for PCI TIO devices.Figure 3-8. RTSI Signal Connection Scheme for PCITrigger <0..6>CtrnSourceCtrnGateCtrnAuxCtrnInternalOutput20 MHz TimebaseMaster TimebaseRTSI Trigger 7RTSI Bus ConnectorRTSI SwitchRTSI Switch