National Instruments NI SCXI-1336, Руководство пользователя

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Chapter 2 Using the SCXI-1129
© National Instruments Corporation 2-23 SCXI-1129 User Manual
Synchronous Scanning
In the synchronous scanning mode, the measuring device, such as a DMM,
issues a trigger, voltmeter complete (VMC), to advance the matrix scan list
at regular intervals. Each interval must be long enough to guarantee that the
matrix has fully settled before the next measurement is taken. Refer to
Hardware-Timed Scanning . For example, you can connect the VMC of
your DMM to the SCXI-1129 through a spring terminal labeled
EXTTRIGIN on the SCXI-1333 terminal block. You can configure the
SCXI-1129 to accept a VMC signal with either rising or falling edges.
If you have more that one SCXI-1129 module, it is not necessary to cable
the VMC to each module. You can bus the VMC onto the SCXI backplane
(Trig 0 to Trig 7) allowing other modules to be triggered as shown in
Figure 2-15.
Figure 2-15. Cabling an External DMM
Handshaking Scanning
The SCXI-1129 supports a handshaking scanning mode. This mode uses
the standard VMC/SCANADVD handshaking scheme. In this mode, the
matrix responds to every VMC trigger by advancing the matrix to the next
state, waiting for the matrix to settle, and then sending a scanner advanced
pulse out on a SCANADVD output trigger back to the DMM.
Backplane
Connector
HVAB RSC
Front Connector
Backplane
Connector
Front Connector
SCXI-1129
Backplane
Connector
Front Connector
SCXI-1129
Trig 0
Trig 1
Trig 6
Trig 7
•
•
•
Backplane
SCXI-1129
EXTTRIGIN
From DMM VMC