66xxA: Synchronize Different System Power Supply Outputs

This can be a challenging problem because the products that could potentially be grouped together have been designed over a period of 20 years. The availability of "hooks and handles" features vary somewhat by each series of products. Also, there are some inherent limits as to how "simultaneously" products can react due to different power supply topologies have different slew rates (i.e. the speed with which the output can change). Linear supplies typically have slew rates in the 100's of microseconds, while switching supplies respond in 100's of milliseconds.

In the most general case, the majority of Keysight power products offer RI/DFI (remote inhibit/discrete fault interrupt). This feature can be used to turn products off simultaneously, either as a result of a specific power supply fault, using the DFI signal, or due to some external event, by pulling the RI contact low. Refer to the product manual for additional information on how to accomplish this. On most products, the RI contact is a latching function. Therefore to turn the products on, once RI has been activated, RI needs to be converted to non-latching. While this capability is standard on the 661xA and 663xB products, it requires a special option, S50, on other series. Contact your Field Engineer to find out about the availability of this option for your product. External components such as relays, or FET switches are also required to control multiple power supplies.

For groups of products which all have SCPI command language, the "Group Execute Trigger" (GET) command can be used. However, timing accuracy is limited by command processing time which can be up to 50 milliseconds. Furthermore, this approach cannot be used with power products that offer sub-addressing. See the programming guide for your product family (available elsewhere on this website) for more information on <*TRG> and <GET> commands. Also, refer to "IEEE Standard Codes, Formats, Protocols, and Common Commands", IEEE STD 488.2-1992 available from the IEEE.

One more alternative is available for systems composed of 66000 modular power system modules and 68xxB ac sources. These products have expanded feature sets, which include "list and trigger" capabilities. These features make it easier to synchronize or sequence power products. For more information, refer to Product Notes 5091-2497 and 5963-7044 for 66000 and 68xxA products respectively.