Hello everybody,
I am fairly new to PLCs, although I have one year left in my three-year Industrial Automation course so I have had some exerience. I have also worked with microcontrollers.
I am creating a project that has a motor (DC brush) and a lead screw to move a device in and out along the lead screw. I am trying to decide on my control options when it comes to speed control of the DC motor and torque sensing of the motor.
The device being moved on the screw must stop and retract 0.5" when a certain torque has been achieved (device putting pressure on something).
My dilemma is that torque sensors are too expensive, so I was considering a simple current sensing circuit with a level detector, and through experimentation determine the correct level at which to retract the motor. The only problem with this is that I was planning on using an H-bridge PWM setup for controlling the motor speed and direction (in which case the current sensing resistor option would be useless).
I have since been looking for some kind of way to control the motor speed without using PWM (strictly voltage control) but the options seem fairly sparse. I've been trying to look into some type of digital voltage controller of some kind. I've also been thinking of using an AB Pico controller for this project. Does anybody have any suggestions for me?
DC Motor is 1/8HP 12 or 24v. Torque being sensed is not much (between 0 and 10 lb/in, or 0 and 1.2 Nm).
Thank you everybody
I am fairly new to PLCs, although I have one year left in my three-year Industrial Automation course so I have had some exerience. I have also worked with microcontrollers.
I am creating a project that has a motor (DC brush) and a lead screw to move a device in and out along the lead screw. I am trying to decide on my control options when it comes to speed control of the DC motor and torque sensing of the motor.
The device being moved on the screw must stop and retract 0.5" when a certain torque has been achieved (device putting pressure on something).
My dilemma is that torque sensors are too expensive, so I was considering a simple current sensing circuit with a level detector, and through experimentation determine the correct level at which to retract the motor. The only problem with this is that I was planning on using an H-bridge PWM setup for controlling the motor speed and direction (in which case the current sensing resistor option would be useless).
I have since been looking for some kind of way to control the motor speed without using PWM (strictly voltage control) but the options seem fairly sparse. I've been trying to look into some type of digital voltage controller of some kind. I've also been thinking of using an AB Pico controller for this project. Does anybody have any suggestions for me?
DC Motor is 1/8HP 12 or 24v. Torque being sensed is not much (between 0 and 10 lb/in, or 0 and 1.2 Nm).
Thank you everybody