RS485 control of Micro SSC?

Support Servo controllers and servos
1

I would like to control a Pololu Micro SSC with a single twisted pair of wires over 500 foot in length. I’ve done a bit of homework and it appears that half duplex RS485 should work, but I’ve never worked with it before so need some advice. Can I use something like this at the pc computer end and this at the Micro SSC end? Is it that simple? Where would the TP connect? I’m not committed to these particular components so if something Pololu or Sparkfun might sell would work better please tell me. Thanks. :slight_smile:

2

Hello.

I don’t have anything specific to recommend that would be better, and it looks like those parts could work. The RS-485 to RS-232 on the servo controller end might not be ideal in that it would be nicer to go to logic-level serial. I generally recommend the newer Micro Maestro over our micro SSC since it has much better error handling options, but the Micro Maestro would definitely require the logic-level serial input.

If you try it, please let us know how it works out!

- Jan

3

Thanks Jan, I’ll probably order those components and give it a try then. I’ll definitely report back.

4

I found a couple SF components that look like they might work. Can I use this SF USB to RS485 converter (sparkfun.com/commerce/produc … ts_id=9505) to send RS485 half duplex from my PC over a single twisted pair to the Pololu Micro SSC?

5

I just took at quick glance at the product pages, but it looks like that’s what you’re looking for.

- Jan

6

Hi,
I am trying to to solve exactly the same problem (long distance operation) but with a Mini Maestro 12. I got the Sparkfun USB-RS485 converter (sparkfun.com/commerce/produc … ts_id=9823) and cannot get the MCC to recognize the Maestro.

If I understand this correctly the USB->RS485->UART should get me a serial TTL signal at the Maestro’s TTL interface.

What am I doing wrong?

Greets
snicks

7

Hello,

The Maestro Control Center relies on a direct USB connection to control and configure the Maestro. It does not use a COM port, so it will not recognize your setup. To control it, you need to write your own program to send serial commands or use some serial-based software that supports the Maestro or the MiniSSC.

Our Serial Transmitter utility is a good thing to start with for verifying that your connection works.

You will also need to make sure that the Maestro is configured to be in UART mode so that it is prepared to accept commands on its UART port, and be aware that the 3.3V level of your adapter is below the level of guaranteed operation for the Maestro, which is a 5V device. It will probably work, but that is one more thing to look into if you have trouble.

-Paul

8

Hi Paul,
thank you for the quick response. I was thinking that the MCC could connect via serial. Your serial transmitter utility helped a lot in tracing the bug. Seems to work now (broken wire). The breakout-board is running on 5V (max spec), so the maestro should be fine with that :slight_smile:
Now I only need to do some VB to get my ROV in the water.

Thanks again
snicks