SD540 Motor Controller

[geezloueez]

The SD504B graph looks much more comparable to the other controllers now. It is amazing how fast those changes were implemented.

Graph link

[Rick]

Will the SD504Bs be FRC legal? What happens to the customers that purchased SD504s?

[mindsensors.com]

Originally Posted by Rick

Will the SD504Bs be FRC legal? What happens to the customers that purchased SD504s?

SD540Bs will be legal.

If you have purchased a SD540 you should have received an email regarding the new model. Please check your spam folder just in case.

[AdamHeard]

Originally Posted by mindsensors.com

SD540Bs will be legal.

If you have purchased a SD540 you should have received an email regarding the new model. Please check your spam folder just in case.

How were you able to "fix" the efficiency issue?

Do you have test data to support this, or just a graph?

[wilsonmw04]

Originally Posted by AdamHeard

How were you able to "fix" the efficiency issue?

Do you have test data to support this, or just a graph?

They pointed to their local suppliers and short supply chains in making these changes. I have been in almost daily contact with mindsensor. They are doing everything they can to give the FRC community a solid product. They are new to this space. Give them time.

[philso]

Originally Posted by mindsensors.com

Thank you all for your feedback!

The SD540 is equipped with a battery safety feature that would disable operation when battery voltage drops below 9.5 Volts.

Based on your concerns we have realized that such a safety feature is not desired by the FRC community, so we have released a model that does not include this feature. The new SD540B will work down to 6 Volts without disabling any operations! Here is our voltage comparison chart:
http://www.mindsensors.com/content/7...540-and-sd540b

Since our design and production facility is local and our SD540s are made here in USA, we have the advantage to implement changes quickly. The new model SD540B is available now and ordering information is here: http://www.mindsensors.com/frc/159-sd540-model-b

Originally Posted by AdamHeard

How were you able to "fix" the efficiency issue?

Do you have test data to support this, or just a graph?

If the output voltage of the SB540B is very close to that of the SPARK, it would translate to losses that are about half that of the SD540 (based on the very comprehensive data from CTRE). This is a very dramatic reduction in losses. Most engineers working on inverter designs would sell their grandmothers to get a 5 or 10% increase in efficiency.

Mindsensors - How do the firmware changes for the SD540B (other than removing the undervoltage-lockout safety feature) change it's behaviour relative to the SD540 to account for the increase in efficiency? Has the switching frequency been changed? Have the switching edge rates been changed? Is the heatsink temperatures different? Is the linearity performance the same as for the SD540? I am not expecting you to give away any major trade secrets but there are only so many ways to increase the efficiency of an inverter.

Originally Posted by wilsonmw04

They pointed to their local suppliers and short supply chains in making these changes. I have been in almost daily contact with mindsensor. They are doing everything they can to give the FRC community a solid product. They are new to this space. Give them time.

The motor controllers are mission critical components. The Build Season starts in 2 1/2 weeks. Once a team commits to using a particular controller and builds their robot, they would have very little time to change to a different controller if they are not happy with it.

[aldaeron]

Originally Posted by philso

The motor controllers are mission critical components. The Build Season starts in 2 1/2 weeks. Once a team commits to using a particular controller and builds their robot, they would have very little time to change to a different controller if they are not happy with it.

This is a very important comment that needs some highlighting.

Below is my summary of this thread, especially for newer teams struggling to read between the lines. This is my opinion only and does not represent my team or any other individual. I have never seen or tested one of these devices in person. Based on the test data released and statements in this thread:

The test data supplied by Mindsensors and others, number of last minute changes, questionable design choices and lack of properly instrumented testing in a truly representative FRC game environment make buying this motor controller a very risky investment at this point, especially for high current, high duty cycle motors like the drive train.

By comparison and using the same publicly released data, the REV Spark controller looks less risky.

If you are considering buying these because they are lower cost than previous controllers, just be aware of the risk you are taking. DC motors have been the main source of power for FRC since its inception and I do not expect that to change. If your motor controllers are not working well, you are very likely to have a bad experience this coming season. If you choose a certain controller for 4-6 drive motors, plus at least one spare, you have invested a few hundred dollars in that controller. If you cannot afford buying a whole new set of controllers mid season, I would stay away from any of the new controllers (MS SD540 and REV spark).

It is possible that these controllers will work fine and all the bugs and concerns voiced in this thread will be fixed. Maybe not. Just take care that you can turn your motors consistently and reliably. No one wants to see a team chasing "motor controller demons" during the competition.

-matto-

[Greg Needel]

Originally Posted by aldaeron

If you cannot afford buying a whole new set of controllers mid season, I would stay away from any of the new controllers (MS SD540 and REV spark).
-

While there is always RISK in trying something new, I don't think it is correct to make a recommendation like this without data to back it up.

Speaking directly about the SPARK, we have done everything we can (including testing them on robots at numerous offseason events, on abusive test bed robots (6 cim - 2 speed drive train weighing 200+ lbs), abuse testing them at higher voltages and higher current, dumping piles of aluminum chips on them, static testing, etc) into it to make sure that it is a hardened controller ready for FRC prime time. The SPARK that is in production right now is actually our 3rd revision of the design, based on the feed back of the above testing. Every time we made a design change we continued trying to break the controller until we felt that it would be WAY out of reach of teams breaking them.

As someone who has been involved with FIRST for 14 seasons, on numerous teams with many blue banners, making sure the SPARK was bullet proof was at the top of our priority list when developing it. We would not have launched the product if I didn't feel 100% comfortable putting them on my own team's robot. 2848 will defiantly be using SPARKs this year (and we are a team that can easily afford talon SRX's everywhere).

We check 100% of our motor controllers at 50 AMPS load on our production line. All that being said if a team does fine an issue we will stand behind it's performance. If any team has any problems with a SPARK, that are not user caused (ours will die in the same way that the talon, victor, and SD540 will from reverse polarity, or wrong hookup) we will replace them.

We designed this motor controller to be low cost so that we could help Rookie teams and those who have budget issues each year, that doesn't mean that we designed it with any less performance than the other controllers on the market.

TL: DR Teams should not have any reservations choosing the SPARK for 2016.

[techhelpbb]

Just a little something I'd like to put out there:

Taking risk is what encourages people to sell products. If your market must have zero chance of issue before any financial or morale return can be made you'll discourage innovation and you'll leave yourself with a small number of choices. Eventually that drives up cost artificially.

Yes - MindSensors decided to make a change in their design. The Jaguars in the past made changes in their design. That's nothing actually new and the Jaguar manufacturing resources took much longer to do it.

FIRST doesn't really let you build your own control systems for competition use. They let you change out modules. Even though my team (FRC11) gave me all their old Jaguars after a bad experience - I as the CSA at several competitions simply took note of these controllers and the experience each team had with them. If you put the time in you could make the Jaguars work - how much time was really up to your team's resources to approach the issues. Even the change MindSensors made addresses a situation which may or may not be a deal breaking issue. I mean they did drive an FRC size robot around with these original controllers and it did move - plenty of people never got that far with the Jaguars.

It should be up to the individuals where there comfort level stands and why. FIRST obviously realizes not every team has the resources to take any risk at all - and for those teams this practice of tightly controlling the control system components is advantageous. It also stops teams from trying to build entirely unique controls in just 6 weeks and then having weird problems with no standards for the FTA/FTAA/CSA to help hunt down to keep the competition playing.

So there's give and take here. I hope the community has some patience with these new guys so they can sort any issues out and polish their work till it represents the best possible outcome. I bought both Sparks and SD540 and I have no regrets because in my particular situation $100 of both was a small price to increase the market diversity.

I write this not because of my trivial investment or any involvement with these companies. I write this because I've put give or take 20 years into FIRST FRC and I personally would rather see some small controlled risk of issues that get addressed than a lock-out that drives not just cost but limitations to the very cool diversity that FRC frequently demonstrates. This isn't FLL. This is high school level and by now as we teach STEM I should hope we can drive metric driven decisions and independent thought.

[AdamHeard]

The time to test these to build confidence for teams was in the offseason at events.

It'd be foolish for teams to run these without being cognizant of the substantial possible risk compared to more established brands.

I know we will be worried about picking teams running these until substantial independent testing in competition proves robustness.

Originally Posted by techhelpbb

Just a little something I'd like to put out there:

Taking risk is what encourages people to sell products. If your market must have zero chance of issue before any financial or morale return can be made you'll discourage innovation and you'll leave yourself with a small number of choices. Eventually that drives up cost artificially.

Yes - MindSensors decided to make a change in their design. The Jaguars in the past made changes in their design. That's nothing actually new and the Jaguar manufacturing resources took much longer to do it.

FIRST doesn't really let you build your own control systems for competition use. They let you change out modules. Even though my team (FRC11) gave me all their old Jaguars after a bad experience - I as the CSA at several competitions simply took note of these controllers and the experience each team had with them. If you put the time in you cloud make the Jaguars work - how much time was really up to your team's resources to approach the issues.

It should be up to the individuals where there comfort level stands and why. FIRST obviously realizes not every team has the resources to take any risk at all - and for those teams this practice of tightly controlling the control system components is advantageous. It also stops teams from trying to build entirely unique controls in just 6 weeks and then having weird problems with no standards for the FTA/FTAA/CSA to help hunt down to keep the competition playing.

So there's give and take here. I hope the community has some patience with these new guys so they can sort any issues out and polish their work till it represents the best possible outcome. I bought both Sparks and SD540 and I have no regrets because in my particular situation $100 of both was a small price to increase the market diversity.

[techhelpbb]

Originally Posted by AdamHeard

The time to test these to build confidence for teams was in the offseason at events.

It'd be foolish for teams to run these without being cognizant of the substantial possible risk compared to more established brands.

I know we will be worried about picking teams running these until substantial independent testing in competition proves robustness.

So you are suggesting you'd punish teams at selection time because they are using hardware you think is an issue?

You haven't even played the first match. That's sort of a bold stance to take. I suppose I could do the same.

I pour money and time into FRC and there are often field and technology problems in the control system.
Perhaps I shouldn't do that any more I mean I take risk doing that. I could cut my losses.
Cause I can actually prove that these issues have cost matches - where as I can make no such claim about these ESC.

You've implied there's a standard for testing here - so I honestly wonder what it might be because an ill-defined standard isn't much of standard. I've got some experience with proposing hardware to FIRST but I can't say that anyone has ever handed me any documents that define the criteria clearly for the levels of test required. I am also fairly certain FIRST is trying to hire a test engineer:

https://jobs-usfirst.icims.com/jobs/...un1offset=-240

Perhaps that role being unfilled contributes hard to say.

[AdamHeard]

It's not a punishment at all.

You're drafting a team and a robot. That robot is made up of many design decisions that may be positive or negative. This wouldn't be any different than passing up a team because their mechanical design isn't robust due to choices they made.

Originally Posted by techhelpbb

So you are suggesting you'd punish teams at selection time because they are using hardware you think is an issue?

You haven't even played the first match. That's sort of a bold stance to take. I suppose I could do the same.

I pour money and time into FRC and there are often field and technology problems in the control system.

Perhaps I shouldn't do that any more I mean I take risk doing that. I could cut my losses.

Cause I can actually prove that these issues have cost matches - where as I can make no such claim about these ESC.

You've implied there's a standard for testing here - so I honestly wonder what it might be because an ill-defined standard isn't much of standard.

[Rick]

My team has been in at least two situations where a desire to save money has cost us a match. I won't get in to details.

In both situations, looking back to the decision to save money was the wrong because we ended up spending more in the long run to fix the problem.

IMO, the potential to save a few hundred bucks is not worth the risk of experimenting with this new controller for this upcoming season for any team.

[techhelpbb]

Originally Posted by AdamHeard

It's not a punishment at all.

You're drafting a team and a robot. That robot is made up of many design decisions that may be positive or negative. This wouldn't be any different than passing up a team because their mechanical design isn't robust due to choices they made.

Just to be clear you'd do so because you have actual reasons for declaring it a negative right?
That's the heart of the issue: what testing do you define as sufficient to take risk on.

Cause I could argue that surviving 10 matches of FRC on 10 designs is enough. You may argue that it's 1,000 matches of 100 designs. That was why I was so very specific to elicit criteria when I started tinkering early in this topic.

It's not much of an experiment without clear expectations.

So if we can put it out there we don't feel they are adequately tested which can drive hardship back to the manufacturer - can we in fairness put out there what adequately tested is?

If we can't define what the actual testing barrier to entry is we are basically saying FIRST is 'all over the place' about how you make a product that is FRC approved and ready for sale. That kind of situation is painful for everyone involved.

To close my previous post: if you view FIRST as an experiment for an educational process/product. FIRST doesn't set their achievement by the minority of technical issues that have happened. They set the value on the overall impact which is greatly positive. These new ESC products haven't had time to set any other experience but it is safe to say that time will tell and I'd like to know for reference how one charts a path to a conclusion because it seems in < 2 months some people have a pretty negative outlook. It sets expectations for people that might want to make FRC products. Is it okay to have a problem when you first release a product if you fix it? How about 2 problems which you do fix...? How about a product that looks a little different? I would hate to hold the teams building robots to the same level of scrutiny. I've seen lots of robots evolve in positive directions after a bumpy start.

[aldaeron]

After re-reading my posts I think I am not stating clearly enough to both REV and Mindsensors that you need to post appropriate, preferably independent, test data. That is what builds confidence. I believe the major reason there was widespread adoption of the last two new motor controllers was the public and independent testing done by Alpha and Beta teams. You need to replicate this level of testing if you want to get widespread adoption.

Our team did not buy Talon SRs the year they came out because of the lack of available test data.

Here is a great example of an appropriate test. Well documented with appropriate methods. It includes photos and part numbers so anyone can repeat it and it is revision controlled. This is the kind of report I would expect to see at work.

Only slightly behind as an example is the Vex Pro Motors page (would have liked to see photos and part numbers of test assemblies, but very, very good).

Originally Posted by Greg Needel

While there is always RISK in trying something new, I don't think it is correct to make a recommendation like this without data to back it up.

For crying out loud - post the data on your website!!

Originally Posted by Greg Needel

Speaking directly about the SPARK, we have done everything we can (including testing them on robots at numerous offseason events, on abusive test bed robots (6 cim - 2 speed drive train weighing 200+ lbs), abuse testing them at higher voltages and higher current, dumping piles of aluminum chips on them, static testing, etc) into it to make sure that it is a hardened controller ready for FRC prime time. The SPARK that is in production right now is actually our 3rd revision of the design, based on the feed back of the above testing. Every time we made a design change we continued trying to break the controller until we felt that it would be WAY out of reach of teams breaking them.

This should also be on your website. Help convince us you have a great new product. As I have noted in this thread and others, your design does look good, just send data to back it up.

Originally Posted by Greg Needel

As someone who has been involved with FIRST for 14 seasons, on numerous teams with many blue banners, making sure the SPARK was bullet proof was at the top of our priority list when developing it. We would not have launched the product if I didn't feel 100% comfortable putting them on my own team's robot. 2848 will defiantly be using SPARKs this year (and we are a team that can easily afford talon SRX's everywhere).

Here's the deal - you had some great looking products last year, but were unable to deliver them due to a variety of issues (our team was bummed to have had to go elsewhere). Great intentions do not necessarily always come through and you should be a little more aware of well-founded concerns that are raised about such key components as motor controllers. Again, providing test data will assuage many of these fears.


techhelpbb has raised an excellent point about offering new and innovative products. I think the new offerings are great and that vendors should continue to offer new products, but the risks should be noted and understood. I think that there is a great community here on CD that would have offered constructive feedback months ago if engaged. The issues being discussed here could have been put to bed long ago at no cost to manufacturers. We all donate hundreds of hours a year to make this program great and hundreds more on CD to help those in need draw on our experience. I hope that in the future that vendors will reach out more to get help.

-matto-