Section 5: Switching and scanning
Series 3700A System Switch/Multimeter Reference Manual
5-16
3700AS-901-01 Rev. D/June 2018
Determining the number of relay closures
The Series 3700A 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.
This option is not displayed if multiple channels are selected. A backplane relay has a close count
associated with it as well; 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:
You cannot query backplane relay closure counts through the front panel. You must use the remote
command interface.
1. Use the navigation wheel to select the channel.
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()
.
Viewing the close or open status of a channel
To determine whether a channel or backplane relay is closed or open, you can view its status using
the front panel interface, remote command query, or instrument web page.
Viewing status from the front panel
To see closed channels on the display of the instrument, press
DISPLAY
. An arrow at either end of
the list of channels means that there are additional closed channels. Use the navigation wheel to
scroll through the list.
