Without seeing the mechanism that sticks out of the frame perimeter it seems that it isn't a bolt that is used to mount something on the frame or hold it together. It also doesn't sound like it is in the bumper zone. As such it would violate the vertical projection of the frame perimeter in the starting configuration.

Re: Al's Annual Inspection Thread
 

Al,
Thanks so much for your insight. I have a question regarding bumpers....

We've come up with a possible bumper mount system, and I'm not quite sure of the legality of it. I'll do the best I can to describe it here. It uses a sort of keyhole shaped hole where the wide end drops over a bolt/screw head and then slides over so that the skinny end is under the bolt/screw head. (Like the holes for hanging things on a wall, see this picture) This allows for a quick drop down and slide over motion for attaching bumpers. Our bumpers are in two halves, both of which would slide in towards the center of the robot if using this idea. To prevent them from sliding back out we thought of using a draw latch similar to the style of the one in this picture. The latch would be mounted on the two halves of the bumpers, to draw them together and hold them firmly in place.

While the latches would be a critical part of the mounting system, they aren't directly mounted onto the robot itself, but rather the wood of the bumpers. I'm not sure if this would comply with the Vertical Cross Section in Figure 4-8 of the manual. I realize that my explanation may not be entirely clear, please ask me to clarify anything you may not understand.

Thank you very much!

Note, I'm sure we can make the system strong and rigid. I'm only worried about the legality of the latches.

Re: Al's Annual Inspection Thread
 

I presented my hypothetical example primarily as a counter-argument, but, since the issue was raised...

I maintain that I can have a CUSTOM CIRCUIT, consisting of a Pneumatic Solenoid Valve and two limit switches.

Per
, this can be attached to either a solenoid breakout or a spike (as well as a motor controller, but that isn't useful in this case.)

Some additional observations...

* R51 includes solenoid breakouts, but it isn't included in the list of power regulating devices in R50.

* I suspect that the intent of Table 4-4 in R51 is that "Solenoid Breakout" should read "Each Solenoid Breakout Output". This would be consistent with the answer to Q352.
-Karlis (learning more than my share today, especially if I work through the stress analysis of our shooter.)

Re: Al's Annual Inspection Thread
 

Since solenoid valves are defined in the pneumatic rules, I don't think you can clump them with other elements & call them a custom circuit. If they are a custom circuit they are not on the allowed list for pneumatic items. The limit switches by themselves cannot connect to a solenoid since solenoid are not on the allowed connections for custom circuit outputs. But then I am not the one inspecting your robot.

I have seen all kinds of strange things from a finger fumble in software. At least on the mechanical side when you disconnect a safety item, you can see it.

Re: Al's Annual Inspection Thread
 

In that case, such a CUSTOM CIRCUIT is not an allowed pneumatic component, per R74. It doesn't matter how you want to define the example, it's not a legal configuration.

Re: Al's Annual Inspection Thread
 

In that case, aren't all pneumatic solenoid valves illegal? Electrically, the Glossary and R40 both define a pneumatic solenoid as a CUSTOM CIRCUIT.

Re: Al's Annual Inspection Thread
 

Pneumatic solenoid valves are custom circuits, yes.

Limit switches are custom circuits, yes.

Putting a pneumatic solenoid valve and a limit switch or two in series may be counted as a custom circuit, I suppose--but if you do that, you do need to be very consistent about "this is one custom circuit".

So... let's take a look at what custom circuits can and can't do. OK, they can connect their outputs to other custom circuits, or to the control system via various means. They can't affect power pathways between elements of the robot control system--but the rule referenced does not include solenoid valves as a control system element.

Electrically, I'd say that that looks good--but only by the letter. Something smells near the spirit--my opinion, not backed up by any rule--yet.

However, pneumatic solenoid valves are also pneumatic components. Limit switches are not. So we've gotta look at the pneumatics rules.

R76 allows wiring of solenoids and other pneumatic devices to be modified to interface with the control system. Note that the control system, as defined elsewhere, does NOT include custom circuits--and we've already established that limit switches are a custom circuit. End applicable pneumatics rules.

So, from an electrical point of view, we're good. From a pneumatics point of view, not so much--again, note that custom circuits are not considered part of the control system, and you're not to modify pneumatic wiring except to interface with the control system.

So where does that leave us?

As one custom circuit, you're introducing a disallowed pneumatics part--it's not COTS, and it's pneumatic, so R75 rules it illegal. That's what you were initially claiming to be able to do. Under R77, pneumatic solenoid valves are legal provided they meet certain constraints--but custom circuits that happen to include pneumatic solenoid valves are not!

As 2-3 separate custom circuits, a particularly picky inspector would probably use R76 to rule it illegal. Pneumatics with wires can be modified to interface with the control system, but it can be argued that a pneumatic is a custom circuit, where the rules are wide open. Personally, I prefer to take the safest route, and figure on the former route. At which point, I note that I've got two custom circuits connected to something that may or may not be a custom circuit, and thus may or may not be legal under the electrical system rules, as well as a pneumatic item with modified wires that aren't connecting to the control system (custom circuits are not part of the control system), which may or may not be illegal, depending somewhat on how lenient the inspectors are.


In short: I can think of one way it's legal, and at least two it could be ruled illegal. Might be a really good question for Q&A to answer (unless Al wants to weigh in first).

Re: Al's Annual Inspection Thread
 

Joel,
In looking back at your question I wanted to be sure that my response is based on your description, it is up to the RI to make that determination once you are inspected. I making an educated guess based on your description.

Karlis,
As to the use of limit switches in series with solenoids. The defining rule in my mind is...
R53
CUSTOM CIRCUITS shall not directly alter the power pathways between the ROBOT battery, PD Board, motor controllers, relays, motors, or other elements of the ROBOT control system (items explicitly mentioned in R64).

Switches used in this fashion are considered as Custom Circuits as there is no other general electrical rule that governs them other than as sensors. If considered as a sensor, by definition they are data input only devices. In either case (sensor or Custom Circuit), neither can be used between the control system and any driven component. If you think about the actions of the robot, it is the intent that when the robot is disabled, all further action is prevented other than that which results from gravity or the natural movement of robot parts when power is removed. Solenoids are considered electrical loads under R51.

Calvin,
The bumper mounting you describe sounds like it could work but an inspector will need to make that decision when working with you. It actually sounds like a unique and desirable solution. What we are concerned with is the reaction of your mounting when physical interaction with other robots and with the field elements occurs. If you ask any inspector, they will almost 100% tell you that they want to see nice, clean bumpers that don't fall off and don't sag out of the bumper zone. You may ask why. It is because we have such respect for the beautiful machines that you have made, it seems counter productive to add a bumper system that doesn't fit the rest of your design.

Re: Al's Annual Inspection Thread
 

Solenoid valves are explicitly allowed per R74 and R77. Other custom circuits are not.

Re: Al's Annual Inspection Thread
 

Day 2 Installment Electricals
1. Motors. While there are wide variety of motors available to teams this year, there are still some limits. Be sure to stay within the limits, 6 of the larger CIMs, a total of 4 Banebots in different models, 4 AM motors, etc. The list is split between tow pages but you only have 2 window, door, windshield wiper or seat motors. Not two of each. Electric solenoid actuators (Not solenoid valves) are limited to 1" stroke and 12 volt, 10 watt total. I hope to see some of these for shooters. For some of these you may need to provide documentation. Please attach that to your BOM or B&T forms so they are all together. Please choose wisely, the battery and main breaker can only pass so much current to your electrical system.
2. Custom Circuits. We expect more of these this year as teams investigate vision processing and passing/throwing. Custom Circuits must satisfy the electrical rules. In particular, they may not "alter the power pathways" and they need to have sufficient insulation to prevent electrical problems and shorts to frame.
3. On the subject of Frame Faults, the cRio and certain cameras have the case tied to the negative lead of the power cable. For this reason, they need to be insulated from the frame. Lexan sheet, non-conductive hardware, etc. are all effective methods. The reason for this, is the possibility of robot to robot contact or electrical issues on the robot that will pass current through frame parts, interrupting power supplies or resetting control components. We want every robot to play every match for the full match.
4. Cameras. These are components we see more of each year. There are rules in other parts of the manual covering cameras, so be sure to read the entire manual. Even if you are only using the camera for collecting demo video, robot rules still apply. The camera must be included in robot weight, and be securely mounted on the robot. Duct tape is not a fastener.
5. Wireless Bridge. Please mount this critical component where it can "see" the field antennas. The inspectors and FTA needs to see the lights especially if you are having issues connecting. This radio has two antennas near the left and right side of the radio. Both are needed for maximum bandwidth in both directions. Metal interferes with the RF signals so try to keep the area near the radio clear of metal and moving parts.

Re: Al's Annual Inspection Thread
 

Would it be a fair statement to say that "Custom Circuits" are used as inputs to the cRio, and not as outputs to anything, such as: motor controller, motor, servo, pneumatic component or mechanism?

The one exception I see is where the CC is used for display or decoration purposes. As an example, an Arduino used to drive a display or LED strip.

Re: Al's Annual Inspection Thread
 

Bill,
In the case of processor controlled custom lighting, the whole system is a Custom Circuit. In that case, the system is a stand alone or it may take input from cRio status or a DIO on the DSC. Custom Circuits make take input from another sensor or even camera. Any command that is generated by a Custom Circuit for robot control must pass through the cRio so that it can be managed by FMS. There are a variety of ways to accomplish this and there is documentation on the FRC website.

Re: Al's Annual Inspection Thread
 

Got it.
The description "Any command that is generated by a Custom Circuit for robot control must pass through the cRio so that it can be managed by FMS." is the decision point. Granted, all CC's must adhere to the rest of the electrical and safety rules as well.

It looks like the RI's really need to be talking with the teams as they pass through the inspection process.

Re: Al's Annual Inspection Thread
 

That's what we do. The first question will be "do you have a custom circuit?" What follows depends on the answer.

Re: Al's Annual Inspection Thread
 

I don't think any safety inspection & discussion, dry-firing or otherwise, is unreasonable. With the amount of stresses place onto relatively small areas a misfire into someone's face can be just as bad as getting a finger stuck in a live #35 sprocket.

Here's an additional thought for winch-style systems:
As the guy who has put my teams' robots on the field for 10 seasons I can say this is the only year where robot transport to a field would make me really nervous if there wasn't a mechanical safety somewhere in the system. I'm a programmer/integrator by trade and losing a finger (even temporarily) would really hurt my career given the stage it's at. If the pneumatic cylinder accidentally fires, the "dog gear" (loosely-termed) breaks, pneumatics looses pressure and the "dog gear" engagement cylinder rail slips, the anti-backdrive wrench eats itself, or the nylon strap attachment breaks then the launcher will definitely fire with many pounds of force.

The build team very easily implemented a hard-pin lock system. The pins are quick-release (McMaster #90293A313) and will have massive ribbons (similar to this) so they're easily the last thing removed before we go behind the driver's station. When the system is under tension yet not in a live-fire environment (i.e. a field), these pins will be in place. This means that no matter what software wants to experiment with or how bumpy that ride from the pits is, our robot will not fire in my or my student's face. It also gives the pit team peace of mind as they remove any energy from the system post-match.