Appendix C Power Allocation

Power Limit Operation

Mainframe Power Limit

 

If the combined power drawn from all of the power modules exceeds

 

the mainframe’s power rating, a power fault protection event will

 

occur. This causes ALL outputs to turn off and remain off until a

 

protection clear command is given. This is explained in chapter 4

 

under “Clear Output Protection Functions”. A status bit (PF) will

 

indicate that a power fault protection event has occurred.

 

The power allocation function lets you programmatically limit the

 

power that can be sourced from individual power modules, thereby

 

preventing the combined power from exceeding the mainframe’s

 

rated output power and causing all the outputs to turn off.

 

For N6702A mainframes operating at 100-120 VAC nominal, the sum of the

NOTE

 

channel power limit settings cannot exceed 600W due to a restriction on the

 

AC line current. There is no restriction when operating at 200-240 VAC nominal.

 

 

Module Power Limit

 

When the power limit has been set to a value less than the maximum

 

rating on a power module, and either the output voltage or the output

 

current increases to a point where the module exceeds the power

 

limit setting, the module’s power limit function will activate. If the

 

power limit is left at the maximum rating, then the power module

 

will not enable its power limit function.

 

On Agilent N673xA, N674xA, N675xA, and N676xA power modules,

 

the power limit function will limit the output power at its

 

programmed setting. A status bit (CP+) will indicate that the output

 

is in power limit mode. When the power drawn by the load is reduced

 

below the power limit setting, the output automatically returns to

 

normal operation - either constant voltage or constant current mode.

 

On Agilent N673xB, N674xB, and N677xA power modules, the

 

power limit function will turn the output off after a power limit

 

condition persists for about 1 millisecond. A status bit (CP+) will

 

indicate that the output has been turned off because of a power limit

 

condition. To restore the output, you must first adjust the load so

 

that it draws less power. Then you must clear the protection function

 

as explained in chapter 4 under “Clear Output Protection Functions”.

 

Note that on these models, it may be preferable for some applications

 

to use the current or voltage setting to limit the output power so as to

 

avoid turning the output off.

 

Power limiting should not be used when Agilent N673xB, N674xB, and N677xA

NOTE

 

power modules are grouped. When these power modules are grouped, you

 

must reset the power limit to its maximum rated value.

 

 

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Series N6700 User’s Guide

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Agilent Technologies N6700 manual Power Limit Operation, Mainframe Power Limit, Module Power Limit