Can you explain the resistor installation to a novice. I understand ground but do not understand how exactly how to install it on the HB25 pin. Are you saying to add a resistor in series with the ground wire that goes to the HB25 ground pin?

I would like to put this problem to bed.

Thanks

I don't have a direct answer to the question. However, my recommendation is to use an easier and supported HBridge, such as the 2.5 Amp Motor Controller - which also supports speed control.

Messing around with difficult 3rd party hardware that wasn't designed correctly is going to be a struggle.

@Ellis

For the HB25, what works is a 1K pull down resistor, between the signal line and the gnd pin. It was was recommended to me, so I tried it an it works perfect for me. Also make sure to add a little delay when you fist initialize the them upon power up as well.

Note to DJ. The HB25 is 25amps, not 2.5, so an equivalent would be something like a Sabertooth 2x25. Twice the price, but also drives 2 motors.

Alan

I needed thi more powerful motor control for the drive system I chose. It at the time was the only reasonable choice I had.

If I add the resister do I need to do the initiation code I have been using to connect to the motors?

@Ellis,

The HB25 is a very good piece of hardware, good motor chipset, fuse and fan and can handle a lot of amps.

There is no erratic behavior and is very important to read the available documentation to understand the behavior.

The HB25 converts a H-Bridge to a continuous servo, HB25 can work single or dual mode daisy chain sharing the servo signal line between two HB25 controllers.

The first initial seconds (5 to 50ms) are very important/critical, the HB25's microcontroller (PIC) checks the signal line to decide the mode (single or dual).

As you can see between power on the EZB, ARC connection to the EZB and run a script the 5 to 50ms are already gone.

To answer to your question, the initialization script is useless to setup the mode, but works to setup the HB25 initial position (stopped).

You can have a proper initialization script in C or Spin (Parallax Propeller) if you upload the code to the micro-controller and the micro-controller will run the code immediately when you connect the power.

The documentation mentions the initial 5 ms to 50ms (different firmware versions) the signal must be low.

That is the reason for the pull down resistor.

Some people complain about the erratic HB25 behavior.

The main reason is: without a pull down the digital port will be in input mode, the logic value is unknown and can float, if floats 2 or 3 cycles during the initial seconds, HB25 will assume the dual mode configuration (daisy chain).

While in dual mode the HB25 does not answer to the standard servo PPM signal instead waits for a special second sequential pulse.

To summarize you should add the pull down 1K resistor, otherwise you are playing roulette.

Thanks everyone. I have wired a 1k resistor between GND and Signal. I will solder this when I am sure it is correctly wired. Please look at picture below and tell me if this looks right.

That is a pull down resistor.