I would suggest either using a fuse, so that any spikes in your power are prevented from getting into your FieldPoint system, or using a voltage regulator so that any unwanted spikes are removed before entering your system. Simply place a fuse in-line with your power supply terminal. The maximum current specifications are listed in the User Manuals for each module. You may go to http://www.ni.com/manuals to find the appropriate manual and determine the maximum current rating. You should choose a fuse such that more than the maximum current is prevented from passing into your system.
As for your 24VDC supply, I would add a voltage regulator between the supply and the connections to your FieldPoint system. You can buy a 24V regulator off the shelf at m
ost electronic component stores.
Additionally, there is module to module isolation on our FieldPoint systems. This means that any spike entering the FP-AO-200 module will not damage other modules in your system. However, if you are using one power supply for both the controller (which will also power the FP-AI-100) and the FP-AO-200 then you are creating a path between all modules in your system. No longer do you have isolation. Therefore, it is recommended that you use one 24V supply for your controller and one 24V supply for your FP-AO-200 module. These should be completely separate power supplies with no path between them.
However, using the voltage regulator should prevent any spikes and using the fuse should protect your system from any spikes that may occur should the regulator fail.
Best Regards,
Justin Britten
Applications Engineer
National Instruments
