Asked — Edited

Ezb 4 And Pulse Out For A Chopper Drive

So Im wondering if the ezb4 will have a command for pulse output. I need 5vdc pulses to the tune of some 20,000 pulses. Less pulses , less travel. More pulses ,more travel. Im not concerned about resolution. Or would I need to write a script and loop the script the required amount of times for the required amount of travel. Will the EZB 4 put out 5vdc out of any of its ports? I will be powering everything from 1 sla battey 12vdc. I think I read that the ezb4 will only put out the same voltage as applied to the input side (12vdc). Thanks Chris


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Need to clarify..... looking for sinking or sourcing outputs, either will work in my case. Thanks Chris


Yes, v4 outputs input voltage on its power pins. In other words, you use a 12v battery with the v4, then 12v will come out the power pins on the ezb. You will need an inline voltage regulator if you want 5v...


I believe he is asking two questions.

  1. If the ez-b v4 is supplied by a 12VDC sla battery what will the voltage of the ez-b v4 signal pins be?

  2. Instead of the normal ez-b pulse width modulation can the ez-b be made to output a pulses? It sounds like he is looking to control some kind of stepper as he says " less pulses - less travel".

For sure you can generate pulse using a script. There are examples in the forum of controlling stepper motors with the ez-b through scripts. I don't know about generating a frequency controlled signal using the ez-b with any accuracy.


Ez-robot will he selling an inline 5v voltage refulator. Haven't announced price yet, but if you ordered the developer's kit it will include one.

Re: pulses. Are describing PWM? If so, yes, the EZ-B can transmit pwm. If something else, your idea of scripting pulses would probably work, but I'll let someone from EZ Robot confirm.



There is mention of a pullup resistor on the digital outputs in some of the hardware tutorials. This would give you an output voltage equivalent to the supply voltage (12V) as long as you keep the load on that output very light. If you draw much current on the output you are going to see a lower voltage. This voltage drop will be a function of ohms law. V=IR where R is the resistance of the pullup resistor. I doubt you can get much current out of these outputs so this may be moot, however it is suggested that you can drive LEDs from these outputs. And your run of the mill LEDs typically draw 5-20mA. I'm waiting on a reply in another thread as to what the pullup resistance is on V4 as well as the rated max output current. As for the states of the output you would get a strong sink for logic low and a weaker pullup from the resistor for logic high with this configuration.


I think what you want is the PWM control.


So to try and clarify, I dont think it will be PWM. This type of unit is normally used with a plc and a high speed out put card. It generates 5vdc pulses. This 5vdc fires an opto isolator in the chopper drive. I neeed to generate 5vdc pulses in an "up" mode and a "down" mode. I can simply use a 840 ohm resistor to drop the 12vdc down to the required 5vdc so that wont be the issue. I will see if i can get the specs from the drive and post them as that may be of more help in understanding. Thanks Chris


That's what PWM does - except you can specify the length of each pulse in PWM. If you need more control, I think you'll need to whip up a 555 timer circuit for the specific speed and pulse length. 20,000 per second can be achieved with the PWM, I feel. You'll need to oscilloscope to tune the speed. Otherwise, 555 timer is your friend:)


Here is what I need, taken directly from manufacturers instructions.

Input Signal Circuit Opto-coupler input with 440 Ohm resistance (5 to 15 mA input current), Logic Low is input pulled to 0.8 VDC or less, Logic High is input 4 VDC or higher Pulse Signal Motor steps on falling edge of pulse and minimum pulse width is 0.5 microseconds Direction Signal Needs to change at least 2 microseconds before a step pulse is sent Enable Signal Logic 1 will disable current to the motor (current is enabled with no hook-up or logic 0)

I will not be using the enable signal. Thanks Chris


Are you attempting to control stepper motors? Is that what a "chopper" motor is? If so, I would highly recommend using a stepper motor controller instead of the EZ-B natively. That way you can offload the processing to a cheap stepper motor controller, rather than use processing power on the EZ-B.


Yes, One stepper motor. The motor is being controlled by a stepper drive(aka chopper drive). The drive for this motor requires a step, and direction set of pulses (5vdc). I may be able to post the entire pdf later when home, if that helps. Thanks again. Chris




Description SureStep microstepping drive, 3.5A per phase, 2-phase bipolar PWM controlled current, 12-42 VDC powered, optically isolated digital inputs for Step, Direction, and Enable. 1/2, 1/5, 1/10, and 1/50 step modes, 0.4-3.5A/phase, idle current cutback, and test mode are all dipswitch selectable (no software required).

I cant seem to link manual so this is its description, it is found at I already own the unit from a different project. Just want to clarify it will work with my new ezb4. Thanks Chris


I would try it with the PWM - and if that works, you're golden. Newer stepper motor controllers do not require the processing of the main brain (i.e. ez-b v4). This is because the EZ-B v4 is doing a billion other things. For example, it is streaming your audio, video, pwm, servos, serial ports, i2c, web server, wifi, and TCP/IP Stack. Performing repetitive things, such as turning on and off stepper motor solenoids is not a great use of it's function. I would recommend trying your device with the EZ-B v4 PWM. If that does not work, then using a newer model stepper motor controller - one that has a popular (i2c/serial) communication interface and relieves the processing of the EZ-B v4.:)