Agilent Technologies L4400 - Manual (Page 162)

150 L4400 User’s Guide
7 L4445A Microwave Switch/Attenuator Driver
Switch state is stored in the instrument. In contrast, the ROUTe:OPEN? and
ROUTe:CLOSe queries always check the actual hardware state of the switch
for verified channels.
For paired operations on the L4445A (using the
ROUTe:CHANnel:DRIVe:PAIRed:MODE command), when you enable
verification on either paired channel verification will be enabled on both
channels. In addition, the module checks for complementary position
indicators on the lower and upper channels of the pair (i.e., the position
indicators should indicate opposite states). If the state of the lower and
upper position indicators are found to be in the same state (due to a
hardware issue), an error is generated and the state of the lower channel
is assumed.
When the paired mode is disabled and pulsed mode is enabled, you cannot
query the open/closed state of the associated channels unless verification
is enabled. While in this mode (single drive operation), only “close”
operations are allowed on the channels (“open” operations are not
allowed). In this mode, a close operation provides a single pulse on the
specified channel.
If you enable verification on a non- paired (single drive), non- pulsed
(continuous drive) channel on the L4445A, the
ROUTe:CLOSe? and
ROUTe:OPEN? commands return the state of the verified device, rather than
the drive state of the specified channel. It is possible to have such a
channel being driven via a
ROUTe:CLOSe command by the channel position
indicators show the channel as open. In these cases, use the
ROUTe:CHANnel:VERify:POSition:STATe? command to determine exactly
which channels are currently being driven.
The ROUTe:CHANnel:VERify:POLarity command sets the logic polarity of
the verification lines on specific channels. You can specify the polarity as
NORMal (active high) or INVerted (active low).
If you have not enabled verification, you can still query the indicator state
of a specific channel using the
ROUTe:CHANnel:VERify:POSition:STATe?
command. This command is useful for channels on which verification is
disabled for activities such as debugging or when verification is disabled
for performance reasons.