View Full Version : [Question(s)] Servo ID

03-03-2013, 05:56 PM
I purchased 6 AX18 servo motors and none of them have ID's numbers on them. How do you know what servo has what number? Is there a way to set the ID to a servo motor??

03-03-2013, 06:15 PM
If you didn't buy them in a trossen kit they are all factory set at 1. You will need to set them with either a arduino or a pc with a usb2dynamixel.

03-03-2013, 06:16 PM
I mean an arduino like the arbotix.

03-03-2013, 06:47 PM
Okay thank you I wasn't aware of that. I have a barebones hexapod and I purchased the AX 18 later. But anyway can you provide a little bit more details on how to set the ID or point me to a link.

03-03-2013, 07:14 PM
Try out Kurt's AX test program. https://github.com/KurtE/AX12_Test on you Arbotix Controller. With the FTDI cable connected you should be able to monitor the serial port to the controller. A simple command list will come up and one of the options is to set the ID. That's what I did when I bought a set of ax18.

Connect each servo one at a time and set it to the number you need.

Hope that is clear.

03-03-2013, 08:44 PM
Okay, thanks I'm going to give it a shot.

03-09-2013, 03:05 PM
Can the ID for an AX18 be set using the FTDI interface? If so what software to use with it?

03-09-2013, 07:40 PM
Yes, all the Dynamixels can have their software set over the serial port. You send a command to set the ID register to the ID you want. Then you have to re-connect to the servo, as it will switch address on the bus right away :-) Dynamixel Wizard (part of the "advanced" tab in RoboPlus, which you can download from Robotis) is the canonical tool to do this, but it works just as well with any software that can send the right serial commands.

03-09-2013, 09:09 PM
A plain FT232RL is full-duplex and the dynamixel bus is half-duplex, so it is not likely to work with RoboPlus without the required full-duplex to half-duplex hardware. If you tie the RXD and TXD pins of the FT232RL together without the additional hardware, then a custom pc program could build the dynamixel packet and use the simultaneous receive as verification of transmission before waiting for the response packet from the servo. RoboPlus does not like that and usually gets confused when receiving the same the packets it sends.

03-09-2013, 10:51 PM
Good point: I thought "the FTDI" meant the usb2dynamixel as I think that is an FTDI chip. (I could be wrong about that.)
I mostly use an atmega32u4 with txd and rxd tied to the bus with 70 ohm resistors, and turn off the receiver when sending data.
I don't know of any way to recover/update firmware without the u2d, so I think one of those is pretty much required.
Does the USB2AX work with firmware recovery? That might be an option.