This appendix discusses the pertinent power and airflow issues for VMEbus boards in a CHALLENGE XL or POWER CHALLENGE XL system.
Cardcage 2 has five available VME slots and supplies approximately 40 watts of +5 VDC power per VME slot (nominally). It receives approximately 200 to 250 linear feet per minute (LFM) of air flow.
There are no VME slots in the cardcage 1 in the CHALLENGE or POWER CHALLENGE systems.
The cardcage 3 (CC3), which is optional on the CHALLENGE XL and thePOWER CHALLENGE rackmount system, supplies up to 20 additional VME slots. The CC3 provides approximately 70 watts of +5 VDC power per VME slot. This assumes the presence of three 505 power boards and one 512 power board. The power boards are included with the optional CC3 upgrade. Cardcage 3 receives approximately 200 to 250 LFM of air flow through the chassis.
 | Note: The CC3 also provides the capability of having multiple VMEbuses for improved system throughput. |
If a VME board requires more than the normal slot power allotment (approximately 40 watts of +5 VDC power per slot in CC2, or approximately 70 watts in a cardcage 3), the board still can be used, provided that the following cooling and power guidelines are met.
The user needs to ensure that the board has the proper air flow (for cooling purposes) and sufficient available power. To help maintain proper cooling (according to manufacturer's specifications), the board may need special custom baffles or a set of non-component, enclosure boards to surround it with sufficient air flow.
| Note: These custom air flow devices must be supplied by the customer. |
To use a third-party VME board that requires more than the normal VME slot power, be sure to observe these guidelines.
The board does not draw more than the amount of power allocated for VME board use.
The board does not exceed the power rating for the VME pins (approximately 200 watts).
The board uses all three P connectors on the system backplane, P1, P2, and P3.
If these guidelines are followed along with the proper cooling requirements, a single VME board can draw as much as 150 watts of +5 VDC power.
In cardcage 2, for example, you can install two 75-watt VME boards (provided the boards are sufficiently cooled). However, as a result, you cannot install additional VME boards, since the VME power allotment would already be saturated. It is also possible to use a single 150-watt VMEbus board in cardcage 2, provided the remaining VME slots are also not used.
In cardcage 3, you can install up to nine 150-watt boards, assuming that all potential power boards (three 505 and one 512) are installed. However, as a result, the remaining VME slots cannot then be used.