When it comes to linear actuators, designing new models and adding functionality can be time-consuming and expensive. To overcome this, we designed the Linear Actuator Control (LAC) board, and a line of linear actuators to work with it. The LAC board gives users the ability to customize certain aspects of Actuonix -P series actuators without having to custom order a device or design a control interface to work with our products.
The LAC Board is a stand-alone, closed-loop control board designed specifically for Actuonix actuators. It simplifies designs by saving the development time, cost, and processor overhead associated with direct motor control. Using an LAC board also offers circuit protection which prevents actuator damage from driving the device against its physical stroke limit.
Which actuators work with the LAC board?
All of our -P series actuators work with our LAC board. This includes:
*Some* larger feedback actuators from other manufacturers are compatible with our LAC board.
Please note that while the LAC board was designed to work specifically with Actuonix actuators, we also added connections for larger actuators from other manufacturers. While many customers have had success using our LAC board with large actuators from other sources, we can not guarantee any level of functionality when using the LAC with anything other than Actuonix -P series devices. The actuator must be a feedback actuator with an internal potentiometer of 8K - 10k. Additionally, we are unable to offer technical support when using our LAC board with 3rd party actuators. Should you want to use our LAC with a 3rd party actuator, we have put together a quick guide to help you with this. For instructions on how to use our LAC board with non-Actuonix devices, please see our LAC Servo Actuator Quick Start Guide.
What you need to use your LAC
What you will need to use an Actuonix LAC Board: Actuonix -P series actuator LAC board Power supply - this must match the rated input for the actuator used A means to control the actuator (one of the 5 recognized input control modes)
Before getting started with your LAC, we recommend you read the LAC board datasheet.
LAC board input control modes
USB mode allows control of the actuator using a computer. In addition advanced settings allow fine control over the controller response. Default settings can be reverted to, using the reset command. When custom settings are turned on, P1, P2, and P3 are ignored. These settings will be saved even when power is cycled. This allows custom configuration for all inputs even when USB is not connected. Details of the DLL are given in a separate document so that custom programs can be created by the customer. An example Labview program is available for download. The Dynamic Link Library(DLL) allows programming in many windows languages including Labview.
This is a standard hobby-type remote control digital servo interface, compatible with servos and receivers from manufacturers like Futaba™ and Hi-Tec™. The desired actuator position is input to the LAC on connector X6 pin 3 as a positive 5 Volt pulse-width signal. A 1 ms pulse commands the controller to fully retract the actuator, and a 2 ms pulse signals full extension. Connector X3 can also be used for the RC control signal, and uses the standard 3 pin 0.1" spacing typical on most hobby servo receivers. Do not connect power to both X6 and X3 at the same time (If the supply voltages differ, you risk damaging either the board or the power supply).
This mode allows control of the actuator using a single digital output pin from an external micro controller. The desired actuator position is encoded as the duty cycle of a 3.3 Volt, 1 kHz square wave on LAC connector X6 pin 5, where the percent duty cycle sets the actuator position to the same percent of full stroke extension. 100% duty cycle represents full extension, and 0% duty cycle represents full retraction. This input is 5V tolerant, however the % duty cycle range must be limited to 3.3V RMS.
This mode allows an actuator to be controlled with just a battery, and a potentiometer to signal the desired position to the actuator – a simple interface for prototypes or home automation projects. The desired actuator position (setpoint) is input to the LAC on connector X6 pin 5 as a voltage between ground and 3.3 V. The set-point voltage must be held on pin 5 to reach and maintain the desired actuator stroke position. The wiper pin of an external potentiometer connects to X6 pin 5. Pins 1 and 5 of X4 can be used as the 3.3V Reference. The other two potentiometer pins connect to these. When a Potentiometer is not used, ensure the control signal ground is connected to LAC ground.
This mode is compatible with PLC devices typically used in industrial control applications. The desired actuator position (set-point) is input to the LAC on connector X6 pin 4 as a current between 4 mA and 20 mA. The set-point current must be held on pin 4 to reach and maintain the desired actuator stroke position.
Start by connecting your actuator, and chosen control source to the LAC board. Then connect your power source. This power source can be a compatible AC power adapter or a battery power source. Please note that this power source must match the rated input of your linear actuator, either 6V or 12V.
When you connect a power source to your board, it will repeatedly scan for an input signal that is valid under any of the five supported interface modes. When a valid signal is first detected, the actuator will self-configure to the corresponding interface mode, and all other interface modes and input leads are disabled until the actuator is next powered on. When the LAC has both a power source and a recognized input signal, the light will come on.
Making changes to end limits, speed and sensitivity is accomplished by rotating the pots associated with each function. When you make a change to your LAC board, you must power cycle the board for the change to take effect.
LAC board customizations
Extension end limit adjustment
This gives you precision control over the extension end limit of your actuator.
Retraction end limit adjustment
This gives you precision control over the retraction end limit of your actuator.
The sensitivity adjusts the tolerance (dead-band) between the target position and the feedback position. A higher sensitivity (smaller dead-band) will mean less error in the final position of the actuator and greater control, but can result in oscillations (‘hunting’) when the tolerance is too tight for the control loop to meet with the actuator being used.
This allows you to reduce the speed of your linear actuator to meet your requirements.
LAC Advanced Configuration Program
We have developed a piece of software that offers more advanced configuration of your LAC board. Most users will not require this tool and it is outside the scope of this article. That said, we have put together a guide to help you get started with the advanced configuration software that can be found here.
LAC board tips
- Below are some tips to help you with setting up your LAC board and using it successfully.
- You can only use 1 control source at a time.
- Power cycle the board any time you make changes.
- When in doubt about any changes to the board’s configuration or whether the board is functioning properly, turn all the blue potentiometers fully clockwise and power cycle the board to apply the default settings.
- When using servo control, the power provided by the red servo wire may be insufficient to drive the actuator. If you use an external power source, cut the red wire. Providing power through both the red servo wire, and an external power source can damage the board.
Frequently asked questions about the LAC board
Is the LAC board IP rated?
No, our LAC is not IP rated. To protect your LAC board from physical damage, we recommend an LAC case. The case is also not waterproof and we recommend mounting your LAC board in a place that is safe from water and dust intrusion.
How to eliminate ‘hunting’ behavior?
To eliminate that "hunting" around the target point the accuracy on the LAC must be lowered slightly, then it should stop. It's because the accuracy of the LAC is higher than the actuator connected to it, so it keeps correcting its position over and over trying to acquire a target point beyond the limits of the actuator it's connected to. Make a tiny adjustment counterclockwise to the accuracy pot and then power cycle the LAC to adopt the new setting. Repeat until it stops hunting.
Can I use the LAC board with a 24V actuator?
Yes, our LAC board is rated for actuators of 6V-24V up to a 4A current draw.
Can I use an LAC board with Arduino?
Yes, you can use an LAC board with Arduino. Here is an article to get you started.
What do I do if my LAC board doesn’t work?
Sometimes, the LAC boards aren't loaded correctly with their default values. Before contacting tech support, please try the following 3 things:
- Double check your connections, and that you have power to the + and – terminals of the X3 or X6 connector block.
- Check that all four of the blue potentiometers on the LAC are turned fully clockwise.
- Power the LAC off and then back on to load the default settings. Can I power my LAC board from USB? No you can not. USB alone cannot provide enough power for the LAC board and an actuator. You will need to provide DC power to the positive and negative terminals of X6 via a battery pack or external DC adapter. This voltage must be the same as the actuator's required voltage . (6VDC or 12VDC). Why won’t the light on my LAC come on? The light will only come on if the board has both power and a valid input signal. If the LED won't come on be sure to check the data sheet to ensure that you have a valid input signal connected properly.
Can I power my LAC board with the USB connection?
No you can not. USB alone cannot provide enough power for the LAC board and an actuator. You will need to provide DC power to the positive and negative terminals of X6 via a battery pack or external DC adapter. This voltage must be the same as the actuator's required voltage . (6VDC or 12VDC).
Why won’t the light on my LAC come on?
The light will only come on if the board has both power and a valid input signal. If the LED won't come on be sure to check the data sheet to ensure that you have a valid input signal connected properly.
We hope this guide has helped you in getting started with the LAC. Below are a couple of other resources to help you with understanding your LAC board.