Search found 10 matches
- Thu Oct 18, 2018 1:06 am
- Forum: Velocity and Position Control
- Topic: Safety stop on loss of Serial Connection
- Replies: 13
- Views: 17588
Re: Safety stop on loss of Serial Connection
Nice one, thanks
- Wed Oct 17, 2018 6:16 am
- Forum: Velocity and Position Control
- Topic: Safety stop on loss of Serial Connection
- Replies: 13
- Views: 17588
Re: Safety stop on loss of Serial Connection
Hello again
Any update on this?
Any update on this?
- Mon Jun 25, 2018 9:43 am
- Forum: General Discussion
- Topic: Questions about the safety wirings
- Replies: 5
- Views: 10093
Re: Questions about the safety wirings
nschoe, the reason the pre-charge resistor doesn't fry is due to voltage drop. In order to drive 5A through a 220Ohm resistor, you would need 1100 Volts (!). Since your battery can only supply (say) 24V, then a maximum of 0.11A can flow through your resistor, dissipating 2.4W (which is still quite a...
- Mon Jun 25, 2018 9:31 am
- Forum: General Discussion
- Topic: Emergency Stop Circuit
- Replies: 9
- Views: 9224
Re: Emergency Stop Circuit
Hi Chris, While the ROS node has a watchdog function that will stop the roboclaw when it stops getting messages on its topic, it still has to send a command to do that. So if the serial/USB comms are broken between the roboclaw and the host PC, it will continue executing its last command forever. So...
- Tue May 29, 2018 9:58 am
- Forum: General Discussion
- Topic: Emergency Stop Circuit
- Replies: 9
- Views: 9224
Re: Emergency Stop Circuit
Looks good although I suspect the 2n222 won't have a high-enough gain (hfe) which is why the original circuit used a mosfet. Unless you have a really low power reed relay I suppose.
Have you tried simulating it? "simetrix" is a useful program for this.
Have you tried simulating it? "simetrix" is a useful program for this.
- Tue May 29, 2018 9:16 am
- Forum: General Discussion
- Topic: Emergency Stop Circuit
- Replies: 9
- Views: 9224
Re: Emergency Stop Circuit
Hello, My solution for this was to make a hardware watchdog out of an "Arduino Pro Micro" and a power mosfet driving a pair of large automotive relays. The code is fairly simple; it waits for a character on the USB COM Port which switches on the relay and resets a timer. An interrupt routi...
- Tue May 29, 2018 9:03 am
- Forum: Velocity and Position Control
- Topic: Safety stop on loss of Serial Connection
- Replies: 13
- Views: 17588
Re: Safety stop on loss of Serial Connection
Hello again
Any update on this?
Any update on this?
- Sun Jan 21, 2018 4:13 pm
- Forum: General Discussion
- Topic: Current flowing from roboclaw to RPi?
- Replies: 3
- Views: 5131
Re: Current flowing from roboclaw to RPi?
The USB ground on the RoboClaw is connected to the main battery ground. This can cause problems with ground loops in my experience, if the RPi is powered from the same battery as the RoboClaw (I have blown up one RPi the same way as you). I recommend these USB opto-isolators to avoid ground loops: h...
- Tue Nov 21, 2017 2:06 pm
- Forum: Velocity and Position Control
- Topic: Reversing directions at limits (Roboclaw vs MCP)
- Replies: 2
- Views: 4964
Re: Reversing directions at limits (Roboclaw vs MCP)
I don't think there is a command to read all of the digital inputs, and the "flip switch" input only works in "RC/Analog" modes. Nor are the limit switch inputs readable via the API. However, you can read the "home" switch input state via the "Read Status" com...
- Sun Oct 08, 2017 3:52 am
- Forum: Velocity and Position Control
- Topic: Safety stop on loss of Serial Connection
- Replies: 13
- Views: 17588
Re: Safety stop on loss of Serial Connection
Hello, I was wondering if you had finished considering this yet? I was quite surprised and disappointed to find that the RoboClaw controllers don't have this safety feature. Given that these drives also don't have any gross error limit setting, then all of the closed-loop commands, including 'distan...