Keithley 708B Reference Manual page 110

Models 707B and 708B Switching Matrix Reference Manual
To set the channel connect rule through the front panel interface:
1. Press the MENU key.
2. Use the navigation wheel to scroll to the CHANNEL menu item.
3. Press the ENTER key (or the navigation wheel) to display the CONNECT MENU.
4. From this menu, select the RULE menu item.
5. Set the rule to BBM, MBB, or OFF.
6. Use the ENTER key to apply the selection.
7. Use the EXIT key to leave the menu.
To set the channel connect rule through the web interface:
1. On the Unit page, in the upper left corner, select the channel connect rule menu.
2. Select Break Before Make, Make Before Break, or OFF.
To set the channel connect rule through the remote command interface:
Use the channel.connectrule command. Refer to the
reference (on page 7-8) for details.
Using sequential connect
During normal operation, the instrument attempts to minimize the duration of any channel action for a
given card type and connect rule. This can result in multiple channels closing or opening
simultaneously.
To prevent simultaneous closing and opening, you can use a sequential connection. A sequential
connection ensures an orderly closing or opening of single individual channels in a channel list. An
orderly action provides for:
•
Repeatable and deterministic channel operation times
•
Minimized power usage
You incur settling times at each close or open operation. If sequential connection is not selected,
action settling times may vary depending on the card type. The total settling time is the sum of the
settling times for each specified channel, plus any user delays that have been set for any closed
channels. To better calculate timing, you can enable sequential channel connections. Deterministic
implies that you can determine the time for a close operation to happen. For example, if you close
three channels and each takes 4 ms to close, with sequential on, it will take 12 ms. With sequential
off, it may be 4, 8 or 12 ms, depending on whether or not the card can close multiple channels at
once.
Opening and closing relays in a sequential manner also uses minimum power. Since only one relay is
closed or opened at any given time, the power used for that action is for a single relay and not
additive.
By default, sequential connections are turned off. The order in which channels are opened or closed
is not guaranteed. This feature also applies to scanning.
The sequential setting affects all channels in the instrument.
707B-901-01 Rev. A / August 2010
Section 2: General operation
Instrument Control Library (ICL) command
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