1260-100X User Manual
Racal Instruments
©
2005
Using the 1260-100X 3-3
Scope of Reset
Event
The 1260-120 design allows the scope of an emergency reset to
be configured. In the default configuration, the 1260-120 opens
only its own relays in response to an external reset event. If
desired, a jumper setting on the 1260-120 may be changed so
that the effect of an emergency reset is global. With the global
reset configuration, a reset signal propagates through the VXI
Local Bus to open all relays on all switch products that are
connected to the same Option-01T.
All Racal 1260-Series and Adapt-a-Switch plug-ins respond to an
emergency reset condition when the scope is set to global.
Certain plug-ins and 1260-Series modules provide the front-panel
contacts for the external switch, and the circuitry to recognize a
reset event. A switch system may make full use of the
emergency reset feature if it includes at least one plug-in or
1260-Series module that has reset recognition capability.
Sequence of
Events
When a reset event occurs, the following sequence takes place:
1. The plug-in that is connected to the external switch
recognizes the reset event and sets a logic latch.
2. All relays are opened on the switch product that recognized
the reset event. If the scope of the reset function is set to
global, then all relays on all switch products connected to
the same Option-01T are also opened. This happens
independently of software.
3. An interrupt is generated to notify the Option-01T that a
reset event has occurred. This informs the Option-01T that
the relays have opened, so that it remains up-to-date on the
relay status.
4. The relays remain open and do not respond to any
commands from the Option-01T.
5. After the reset condition is removed (the external switch is
returned to its normal position), the relays remain open until
otherwise commanded by the Option-01T.
Other Adapt-a-Switch plug-ins and 1260-Series modules that are
equipped to recognize an emergency reset are configured and
operate the same way as the 1260-120. It is important to note
that a global reset condition opens relays on all plug-ins and
1260-Series modules that are connected to the same
Option-01T, regardless of whether they are equipped with the
interface for the external reset switch.
