User`s manual

DIAGnostic
The DIAGnostic command subsystem provides control of the FET multiplexers.
Subsystem Syntax DIAGnostic
:FETS <mode>
:FETS?
:FETS
DIAGnostic:FETS <mode> selects either external digital bus or backplane control
of the FET multiplexers.
Parameters
Parameter Name Parameter Type Range of Values Default Units
<mode>
boolean OFF | 0 | ON | 1 none
Comments •
0
or OFF = backplane control; 1 or ON = digital bus control.
• The channels on FET multiplexers (HP E1351A, E1352A, E1353A, E1357A, and
E1358A) that are part of the voltmeter virtual instrument can be closed using
either the VXI backplane or by the external digital bus connected to the modules.
The digital bus should be used when maximum scanning speed is required.
• When only FET multiplexers are present in a system, the digital bus is
automatically used. When a relay multiplexer is present, then the digital bus to
the FET multiplexers is not used. Instead, all switching of channels is done using
backplane control.
• When the digital bus is used to communicate with FET multiplexers, a scan list is
downloaded to the FET multiplexer and then the digital bus routes the "Voltmeter
Complete" signal from the voltmeter to the FET multiplexer. The falling edge on
the Voltmeter Complete signal causes the FET multiplexer to advance to the next
channel.
• The command DIAG:FETS 0 sets the mode to be backplane control. This mode
must be used if both FET and relay multiplexers are in a scan list.
• The command DIAG:FETS 1 sets the mode to be digital bus control. This mode
must be used to obtain the maximum speed from FET multiplexers. This mode
can not be used if any relay multiplexer channels are in the scan list.
:FETS?
DIAGnostic:FETS? is used to query which mode of operation is in effect. The
returned number has the following meaning:
0 = backplane control
1 = digital bus control
135 Command Reference Chapter 5