Linear Actuator with Feedback and 12" Stroke (LACT12P)

The LD Series of linear actuators by Iowa Export-Import are 12V DC gearmotors that use a worm drive to move a shaft back and forth along its length. The actuator has a dynamic load rating of 110 lbs (50 kg) and a maximum speed of 0.5 in/s (1.3 cm/s). It is rated to withstand up to 550 lbs when not moving, and the worm drive ensures that the shaft will hold its position even when unpowered. Two limits switches safely stop the motor at either end of its range, while diodes allow it to reverse direction after reaching a limit point. The actuators are mostly metal, and the entire case is sealed to protect against dust and water (rated IP63).

The linear actuators are available in a variety of lengths and with optional potentiometers that are linked to the shaft position, for use in feedback systems. Mounting brackets are available for attaching the actuators to a structure; two are required for each actuator.

Using the actuator

To test-drive the actuator, simply connect a power source of up to 12 V to the motor leads. Reversing the applied voltage will reverse the direction of motion. A motor controller or motor driver is required for electronic speed and direction control. We recommend our Jrk Motor Controllers for use with the feedback actuators and the Pololu Simple Motor Controller 18v7 for controlling the actuators without feedback, though many of our other motor controllers and motor drivers are capable of powering this actuator.

Dimensional drawings

Diagrams of the linear actuators are shown below. The versions that include potentiometers have a larger gearbox, so their overall size and weight is larger. For more detailed information, including the retracted and extended lengths of each version, see the appropriate datasheet (click the Resources tab above).

Actuator leads

Each actuator has a 3-foot-long cable. On actuators with feedback, this cable is terminated with special female connectors as shown in the left picture below, one for the three potentiometer leads and another for the two power leads. These connectors match male versions on the extension cable for LD linear actuators. Actuator versions without feedback have two unterminated, stripped power leads as shown in the right picture below. Linear actuators without feedback do not have cables that are compatible with the linear actuator extension cable.

Using a jrk motor controller with a linear actuator with feedback

The feedback feature included with our jrk motor controllers make them a great solution for precisely controlling our linear actuators with feedback. Our settings file for the jrk configuration utility makes setup easy, eliminating the need to calibrate the feedback and tune the PID constants. To get started, follow the steps below:

1. If you have not already, read through the Jrk USB Motor Controllers User’s Guide and downloaded its drivers and configuration software.
2. Connect your jrk to a PC with a USB cable and launch the configuration utility. The red LED should be on, and the green LED should be flickering quickly.
3. Download the jrk 21v3 settings file for use with LACTxP (1k txt). The settings in this file work with any length actuator that has a feedback potentiometer (model LACTxP), and they were tested on the jrk 21v3, which is powerful enough to drive these actuators in typical applications. These settings should also mostly work for the higher-power jrk 12v12, though a few of them (e.g. current calibration) might need to be adjusted.
4. In the configuration utility, choose File → Open settings file (Ctrl + O), and navigate to the location of the settings file you downloaded in step 2.
5. With your power supply off, connect your linear actuator to your jrk using the connections shown in the picture to the right. The picture shows a jrk 21v3, but the connections will be the same if you use a jrk 12v12.
6. Turn on Power.
7. On the Error tab, choose “Clear Errors”. The “No power” and “Feedback disconnect” errors will clear. The red LED will turn off, and the yellow LED will blink slowly.
8. On the Input tab choose “Set Target” to move your actuator to the target position.

While this setting file gives precise control over most of an actuator’s range, you might find decreased performance very near the extremes due to the limit switches. If your project requires better control near the actuator’s limits, you might need to recalibrate the feedback settings for your particular actuator.