HP FET MULTIPLEXER E1351A/53A manual Clos?

Comments Isolation. The direct terminals provide a more accurate measurement than the tree terminals or the analog bus connector as the signal does not have to travel through the extra FET switches. The SCAN:PORT NONE command opens the tree isolation switches and isolates the direct terminals from the tree terminals and the analog bus connector.

The default value of SCAN:PORT is NONE for reset and power-on. If you have not specified a different SCAN:PORT since reset or power-on, you do not need to execute this command. You can also use the direct terminals with SCAN:PORT ABUS. The signal for a given closed channel will then be available at the direct terminal for that bank, the A tree terminal and the analog bus connector.

Closing Channels. The FET multiplexer module only allows one channel per card to be closed at a time, except for SCAN:MODE FRES (4-wire resistance measurements) where two channels are closed. You can close a channel on two different cards in the same instrument at the same time.

The SCAN <channel_list> command allows you to specify a list of channels to be closed sequentially. The FET multiplexer module uses a break-before-make procedure, so closed channels are opened before the next one on the list is closed. The channels are advanced according to the TRIGger mode selected.

Query Open/Closed Channels. The CLOSe? <channel_list> and OPEN? <channel_list> commands determine if the channel(s) in the channel list are open or closed, respectively. (The query command does not determine if, in the event of a hardware failure, the channel remains open/closed.) For example, to determine if channel 109 is closed, execute:

CLOS? (@109)

A response of "1" indicates the channel is closed, and a "0" indicates the channel is open. The reverse is true for the OPEN? <channel_list> command. The response for the OPEN? and CLOSe? commands are:

CLOS?	1	= Closed
	0	= Open
OPEN?	1 = Open
	0	= Closed

To find out which channel on a card is closed, use a channel list for the card.

CLOS? (@100:115)

and enter the response into a string variable. If channel 09 is closed, the response will be:

0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0

NOTE: You must read the response after sending a query command or the switchbox will generate an error.

Chapter 3 Using the HP E1351A/53A FET Multiplexer Modules 33