I am interested in using a single board RIO for a control application. I need to know whether the board can be immersed in oil? I know that one of the requirements for this is that there are no electrolytic capacitors, is this the case.
The board does have an electrolytic capacitor, right next to the power supply. We recommend against submerging the sbRIO in anything. First, it has not been tested, and second, a short is definitely possible.
To be slightly more specific, the capacitor in question is C18, next to the power supply.
However, I really want to stress the point that submerging the sbRIO in any liquid has not been tested by NI, and could lead to board failure.
I don't know much about the standards or requirements for oil immersion. I know that Single-Board RIO was not designed with oil immersion in mind. Also, I know that Single-Board RIO currently includes at least 1 electrolytic capacitor in the power supply design.
Single-Board RIO is intended to be installed in a suitable enclosure for the environment in which it will be installed. If you need to install Single-Board RIO in an environment with oil, I suggest finding an enclosure that can be sealed to prevent ingress of oil that may contact the PCB assembly.
Just curious, are you aware of any single-board computers that are inherently designed for submersion without protection? That one is a new one for me. National Instruments has experience with Conformal Coating to protect components on a PCB from ingress of oil/dirt/water, but it is not intended to protect at immersion levels.
I absolutely agree with what D Smith has said. We haven't tested submerging the sbRIO in oil (pure Mineral Oil?) and are unsure of what components that could cause the system to fail inside such a system.
Just out of professional curiousity, what kind of oil are you submerging the system in? Is it pure mineral oil? Some mineral oils have additves that can be conductive, so I would be absolutely sure that it is 100% pure. Also is this for cooling purposes. It is very surprising that the Single-Board RIO would get any where near hot enough to require this kind of cooling, so will this be apart of some much larger system? Can you tell us what application that it will be in?
Thanks for the responses. I do a lot of work in the offshore sector on ROV's (remotely operated vehicles). These ROV's are basically remote controlled submarines. They can operate to a depth of 3000m. It is common practice to submerge all the components in oil for pressure reasons. We can fill an enclosure with oil and compensate it. Most of the enclosures are done this way and the boards have been designed with this in mind. It helps in reducing the expense of the enclosure required for the electronics. The application i had the Sbrio in mind for was for a multi use hydraulic tool controller. Again, the common practise in this case is to have the controller board in the same enclosure as the solenoid valves.
To answer another question. The oil used is the same hydraulic oil used by the system. Usually Tellus 32. Although for some applications (High power boards) a benefit of the oil is its cooling properties this is just an added benefit and not the purpose for the oil.
I would first Conformal coat the board. This is a common practice for circuit boards in harsh\dirtly environments. This *should* add additional protection from shorts. It's clear, so it does not mask components visually.
From my experience, conformal coating is 'safe' for most all circuts. (It does make repairing a component on the board very messy.
You can buy a can of Conformal coat and 'dip' the board yourself. Of course you need to mask the connectors.