Engineering Notes by Oriental Motor

MOTOR CHALLENGE 4: Creating Reciprocating Motion Without a PLC or External Sensors

[fa icon="calendar"] Oct 30, 2018 1:38:20 PM / by Johann Tang

Johann Tang

Automation is great for repetitive tasks, such as test fixtures for a process that has to repeated.  In this post, we will explain how to perform a reciprocating motion (back and forth cycles) with a product that does not require a PLC or external presence sensors, which can help speed up design cycles.

Reciprocating motion test fixture We will use an endurance testing application example where the purpose is to test a push button repeatedly for 10,000 cycles.  To perform the test, the red button needs to be pressed 10,000 times.  An actuator will need to move up and down repeatedly in order to provide the pressing motion.  An external pressure sensor or presence sensor would be required to provide a signal to tell the actuator when to stop pressing and move back up to a home position.  Typically, a PLC is also required to manage these I/O signals.  This means more parts, knowledge, and labor are necessary for a successful integration.

CHALLENGE: Create reciprocating motion without a PLC or external sensors

Conventional Equipment: Endurance test equipment that receives inputs from an external sensor with a host PLC and presses the push button 10,000 times.

Problems with Conventional Equipment: 

  • Many components need to be integrated including motor, actuator, driver, sensors, and PLC.
  • An external host controller (PLC) is required, which drives up the cost.
  • External sensor(s) are required.
  • More knowledge, inventory, and labor are necessary to integrate the entire system successfully.

SOLUTION: EAC Series motorized cylinders with built-in absolute position sensor & advanced point-to-point programming

Use a pre-assembled linear actuator with built-in absolute position sensor to eliminate sensors and the PLC, and reduce time for installation.  Our EAC Series motorized cylinders utilize the same Alphastep Hybrid Control technology as well as a built-in absolute position sensor from the AZ Series.  This absolute position sensor (ABZO sensor) manages absolute position information mechanically, thus also eliminating the need for a backup battery often required for systems using absolute encoders.  The EAC Series electrical cylinders are also offered with an optional, pre-assembled linear guide to handle moment loads, which eliminates the need for an external guide.  Due to the pre-assembled components and built-in absolute positioning functions, a more simplified equipment can be designed.stepper-motors-az-absolute-sensor

The role of the PLC in this example is to send command signals to the driver in order to tell the actuator when and how far to move up and down.  With advanced point-to-point programming from the AZ Series stored data drivers, a continuously repeating (looping) motion can be programmed without a PLC. 

Additionally, the driver's push motion function can be used to sense the load torque.   For example, if you set the push motion at 20%, a dedicated TLC output signal can be used to indicate when that 20% torque has been reached, and the actuator can be programmed to move back up to its home position when it happens.  Essentially, a system can be configured where the actuator comes down and presses the button, then when the actuator senses a 20% load torque from pressing the button, it will automatically move back up to the home position, then repeat.  Additional programming can be added to start the operation when the actuator completes a homing operation, or when the system provides a READY status.  Any of the physical or remote I/O signals can be used to start a specific sequence of motion (see Event Trigger function).

To set up the motion data and system parameters, or to monitor the statuses  of the EAC Series, please download our powerful MEXE02 product support software.

Reciprocating motion test fixture with EAC cylinder-1

Advantages offered by EAC Series: 

EAC cylinder & driver

  • Pre-assembly saves time & labor
  • Built-in absolute sensor can eliminate external home & limit sensors as well as an external position sensor (encoder)
  • Built-in push motion function can elminate pressure sensors
  • Built-in loop programming eliminates PLC
  • High efficiency design for high duty

RESULT: A more simplifed machine can be designed faster with less labor

WATCH how easy it is to program the reciprocating motion with the MEXE02 software.

Watch more software training videos, such as push motion setting or palletizing operation.

Topics: Linear Actuators

Johann Tang

Written by Johann Tang

Johann Tang is a Product Specialist at Oriental Motor USA Corp. with over 15 years of expert knowledge and experience supporting applications of various types of electric motors, gearheads, actuators, drivers, and controllers.

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