Keithley 708B Reference Manual page 543

Appendix C: Status model
When the thermal aspect event occurs on Node 15, the following sequence of events will occur:
1. On Node 15, with Bit B9 of the Questionable event register enabled, when the thermal aspect
event occurs, Bit B9 bit sets (status.questionable.condition) which causes Bit B9 to be
set in status.questionable.event. This in turn causes the Questionable event summary bit
(QSB) to set.
2. With QSB set, and Bit B3 of the System node enabled (status.node_enable), Bit B3 of the
Status Byte register (Node 15) sets. This in turn causes the System node summary bit to set.
3. With the System node summary bit set, and Bit B1 of the System2 summary event register
enabled (which is Node 15), Bit B1 of the System2 register sets. This in turn causes the System2
event summary bit (EXT) to set.
4. With EXT set, and Bit B0 of the System summary event register enabled, Bit B0 of the System
register sets. This in turn causes the System event summary bit (SSB) to set.
5. With SSB set, and Bit B1 of the Service request enable register enabled, Bit B6 of the Status Byte
register sets. This in turn initiates a request for service (SRQ).
6. When your program performs the next serial poll of the Master Node, it will detect the interlock
event and can branch to a routine to service the request.
The System Summary Registers are shared by all nodes in the TSP-Link system. When a bit in a
system register of Node 15 sets, the same bit in the master node system register also sets.
The following commands (sent from the master node) enable the appropriate register bits for the
above example:
Node 15 status registers: The following commands enable the events for Node 15:
node[15].status.questionable.enable = status.questionable.S1THR
node[15].status.node_enable = status.QSB
The affected status registers for the above commands are indicated by labels (1) and (2) (see the
"TSP-Link status model configuration example" figure below).
System registers: The following commands enable the required system summary bits for Node 15:
status.system2.enable = status.system2.NODE15
status.system.enable = status.system.EXT
The affected system registers for the above commands are indicated by labels (3) and (4) (see the
"TSP-Link status model configuration example" figure below).
Master Node service request: The following command enables the service request for the
measurement event:
status.request_enable = status.SSB
The affected status register for the above command is indicated by labels (5) and (6) (see the "TSP-
Link status model configuration example" figure below).
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Models 707B and 708B Switching Matrix Reference Manual
NOTE
707B-901-01 Rev. A / August 2010