Keithley 708B Reference Manual page 112

Models 707B and 708B Switching Matrix Reference Manual
Determining the number of relay closures
The Models 707B and 708B keeps an internal count of the number of times each switching card relay
has been closed. The total number of relay closures is stored in nonvolatile memory on the switching
card. Use this count to determine when relays require replacement (see the card documentation for
information regarding the contact life specifications).
Relay closures are counted only when a relay transitions from open to closed state. If you send
multiple close commands to the same channel without sending an open command, only the first
closure is counted.
The counts reported for the following cards indicate the number of closures since the last power cycle
of the card:
7072
7072-HV
7173-50
7174A
For all other cards, the number of closures are the closures that have occurred over the lifetime of the
card.
To view the close count for a channel from the front panel:
1. Use the navigation wheel
2. Press the CONFIG key.
3. Press the CHAN key.
4. Use the navigation wheel to scroll to the "COUNT" menu item.
5. Press the ENTER key (or the navigation wheel) to display the close counts.
6. Use the EXIT key to leave the menu.
To view the close count for a channel from the web interface:
1. From the list on the left, select a slot with an installed card.
2. Right-click a channel. The Channel Configuration dialog box is displayed.
3. Check the value in the Closure Count box.
You can also work with channel patterns using the command channel.getcount().
Identifying installed switching cards
Press the SLOT key to scroll through the model numbers, descriptions, and firmware revisions of the
installed switching cards.
707B-901-01 Rev. A / August 2010
NOTE
to select the channel.
NOTE
Section 2: General operation
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