What is the Use of the Extra P1 Connector on the Back of a VXI Controller?Hardware: VXI/VME/MXI
Problem: I want to use a 2-slot National Instruments VXI controller in a 3rd party, D-sized VXI chassis. To do this I need to add an extender from the back of the VXI controller to the backplane of the VXI chassis. I understand the use of the P1 and P2 connectors, but what is the use of the second P1 connector on the back of the controller? Also, I have connected the controller in my D-sized chassis with only the P1 and P2 connectors extended and the controller boots correctly, should I be aware of any potential problems? Solution: The second P1 connector is definitely needed for the VXI controller to work properly. The pins that are located on that connector supply additional power to the controller. Under light loads, it is possible that the controller can boot without the second P1 connector (since the power pins are collected to a common source on the board), but that system would be very unstable. Under heavy loads, there are numerous things that can go wrong if the second P1 connector is not connected properly. One of the more likely scenarios is that the extra load will cause one of the power rails to sag. This would in turn cause the VXI module to not function properly, but it could also permanently damage the board. There is also a possibility that this configuration could cause too much current to be drawn from the power pins of Slot 1. In this scenario, the power pins could act as a fuse and eventually fail. These are just a few of the reasons why it is very important to connect the second P1 connector, in addition to the P1 and P2 in the first row, when inserting an extender between the VXI controller and the VXI chassis backplane. Related Links: Attachments:
Report Date: 05/08/2003 Last Updated: 05/08/2003 Document ID: 2X7C3RL8 |
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