Racal Instruments 1260-100, Manual, Page: 28 / 53

1260-100/101 Adapt-a-Switch Carrier Module User Manual
Using the 1260-100/101 3-2 Racal Instruments

1998
Interface
Select Adapt-a-Switch plug-ins and 1260-Series modules have a
pair of front-panel-mounted connector pins. You may connect
these to an external device such as a mechanical switch. When
the switch is opened, all relays on the plug-in or module are
immediately opened.
An example of a plug-in that provides the emergency switch
interface is the 1260-120 Power Switch. All other plug-ins and
1260-Series modules that provide the switch interface operate in
the same manner as the 1260-120.
Normal State of
External Switch
If desired, a jumper setting on the plug-ins allows it to
accommodate a normally-closed external switch. Normally-open is
the default. Refer to the individual plug-in manual.
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.