Connecting ClearPath motors to the BB Controller

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Connecting ClearPath motors to the BB Controller

Post by Doug » Sun Nov 13, 2022 4:28 pm

As good as the internal drivers are in the Buildbotics Controller, they simply cannot meet every possible need. This is why we exposed the step and direction inputs to the internal drivers onto the new DB15 connector on the back panel.

Today, I spent some time getting a couple of ClearPath CPM-SDSK-2301S motors connected and running.

ClearPath makes a series of motors that have their drivers built into the motor. My goal was to connect two of these motors in parallel to a single output. Here's how I did it. If you want to run a single motor off of a port, then you don't need to make a 'Y' cable.

I bought their control cables along with the motor.

The control wiring is exposed on an eight-pin connector on the back of the controller. Pin-out for that connector is called out on page 45 of the ClearPath User's Manual.

First I made a single parallel cable out of the two cables that I bought.
  • Cut the off plugs that are meant to connect to the BB Controller.
  • Wire the Input A+ wires (white wires on pin 3) together.
  • Wire the Input B+ wires (black wires on pin 2) together.]
  • Wire the Enable + wires (blue wires on pin 4) together.
  • Wire all of the grounds together (Input A- {brown on pin 7}, Enable- {orange on pin 8}, Input B- {yellow on pin 6}.
When the cable was completed, I had a 'Y' cable with the original plugs that connect to the motors on one end, and four exposed wires on the other.

Note, if you aren't planning on running two motors off of single port, then you don't need to make the 'Y' cable. Just cut one end off, so you can connect the four wires to the DB15 breakout board.

The best way to connect to the DB15 connector is through a DB15 breakout box. Make sure you get the right sex.

Now following the, DB15 Breakout Box section in the Buildbotics User's Manual, make the following connections to the DB15 breakout box:
  • Connect the grounds , Input A-, Input B-, and Enable- to a ground pin (14 or 15) on the DB15 breakout box
  • Connect the Input A+ wire to the 'dir' input for the motor port that you are using.
  • Connect the Input B+ wire to the 'step' input for the motor port that you are using.
  • Connect the Enable+ wire to the enable input (pin 9)
  • Connect the DB15 breakout box to the back of the BB Controller
You will also need to connect your motors to a power source. Mine run on DC, so I hooked them up to the same DC power supply that I was using to run my BB Controller. The ClearPath User's manual shows how to make this connection. Be careful, because they say that a reverse polarity connection will destroy the motor.

The motors should have come with a USB cable (I don't remember whether this was included or if I had to buy it). In any case its a USB type A to a USB Micro-B cable and you will definitely need one.

You will also need to download a free app called MSP (Motor Setup Program). It runs on Windows. A link to the software is provided in the manual. Download it and install it.

One at a time, connect your motors to the PC using the USB cable. Then start MSP. You will be prompted to
autotune the motors. If you have them installed on your machine, you should do this.

When you are running MSP, take note of the number of pulses per revolution. The default is 800 but you can change it to other numbers. This is important because you will use it to set up micro-stepping and step angle in the BB Controller. For instance, if you tell the BB Controller that the step angle is 1.8 degrees, that's 200 steps per revolution. Then, if you set micro-stepping to 1/4th, you get 800 steps per revolution to match the motor.

I haven't gotten quite this far yet, but it might be the case that each step sent to the ClearPath is interpreted as two steps. This may happen because some drivers interpret each signal transition as a step. The BB Controller sends a pulse with each step, which is two transitions. If that's the case, then you would get the right turn distance by making setting micro-stepping to 1/2 rather than 1/4.

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