memetis valves and chip actuators are current controlled to ensure that the very thin shape memory alloy actuator does not overheat during operation. But don't worry! The control mechanism is as easy as for an LED driver circuit.
This page will introduce you to the electronic control options that memetis offers for initial product testing and prepare you for integrating the electronic control in your device prototype after the first testing stage is complete.
memetis valves and chip actuators are current controlled to ensure that the very thin shape memory alloy actuator does not overheat during operation. But don't worry! The control mechanism is as easy as for an LED driver circuit.
We have created two versions of electronic control units (ECUs) to meet your needs for initial testing. ECU-S1 enables very simple testing of valve and chip actuator functionality, while ECU-P2 is made for more advanced valve testing when automation or current optimization is desired.
The use of ECU-S1 is straight forward – the on/off button turns the current supply to your microvalve or chip actuator either on or off. In the case of the ECU-S1-nc for memetis normally-closed (NC) valves, the valve is powered and opened with a 500 mA continuous constant current. This current enables the opening of memetis NC valves within the temperature range of -20 °C to 60 °C.
NB! There are several ECU-S1 versions corresponding to the different memetis products: see the different ECU-S1 data sheets. As current requirements differ between the valve and the chip actuator types, it is important to use the right ECU-S1 version!
The programmable ECU-P2 offers you to test two memetis NC microvalves with different current profiles to optimize electrical power use and valve performance in your exact setup (ECU-P2 data sheet). This can be done via the graphical user interface by memetis that can be downloaded on our website. Alternatively, the valve control can be automated by programming the ECU-P2 with Python.
This ECU can be used to control two normally-closed (NC) memetis valves simultaneously or a single bistable valve with the right adapter. Please note that the ECU-P2 is not suitable for chip actuators!
Skip down to the support info for electronic integration.
The ECU-P2 graphical user interface is made to allow operating memetis valves from your computer screen, tablet or Raspberry Pi without having to code in Python.
Here you will find download links for the ECU-P2 graphical user interface.
Watch this ECU-P Interface Installation Video to learn how to perform your first test.
The Quick Start mode, see selected on the picture on the left, allows you to turn NC valves on and off using the enable/disable buttons similarly as with the ECU-S1. In this mode the NC valves, for example, are opened and kept open with a 500 mA continuous constant current.
To select the right current for your memetis product in Quick Start mode, click on the white button "NC Valve ..." and choose the product that you need to power.
Note! There are two options for bistable valves. Please consult the data sheet of the valve that you have in order to select the right current. Too high current can destroy the valves by over-heating the actuators.
The Manual Control, see selected on the picture on the left, is the mode where the current profile can be chosen and the exact values* set. A total of five types of current profiles can be selected by clicking on „Pre-defined profile“:
Pre-defined profile - same as the Quick Start mode
Continuous - a single continuous current powers the valve for as long as the output is enabled ("Enable" button for each channel). In this case, the current and slew rate can be set manually.
Pulse - current type specifically for bistable valve testing where a constant current for a set duration of time is supplied to switch between the bistable valve states.
Peak & Hold - a peak current for a set duration of time is followed by a hold current that is kept until the valve is turned off. In this setting, both the peak and hold current can be set, plus the duration of the peak current.
Peak & Timeout - similarly as in Peak & Hold, both the peak and hold current strengths can be set, as well as the duration of each.
* Please check the recommended start values on the specific product data sheets.
Too high current can destroy the valves by over-heating the actuators.
If you have further questions, don't hesitate to reach out to support@memetis.com!
Depending on the selected current profile type, only the relevant value settings will be available for changing. The others will be disabled (Windows) or not appear at all (Mac).
For example, the Peak & Timeout setting allows changing peak current and duration, hold current and duration, as well as slew rate, i.e. current rise and fall time, see blue explanations on the image to the left. The other information that appears when controlling valves via the ECU-P2 graphical interface is explained in grey.
NB! If the ECU-P2 is shut off, the values won't be stored. The next time you want to use the interface you will need to change the default values again.
memetis ECU-P Interface allows controlling additional fluidic components that have compatible drivers. For example, all fluid system components in our valve test kits - Lee and Bartels pumps, Sensirion flow sensors - can be easily controlled within the graphical interface.
Programming the ECU-P2 with Python enables you to automate the valve control. The library that we offer lets you perform the same functions as using the graphical interface in the manual mode.
First, follow this guide to install the library and make sure the communication with your ECU-P2 works.
There are multiple ways how to implement the electronic control/connection in your setup. Below we offer some options to begin with!
The NC valve pins are 3 mm high, 0.4 ± 0.05 mm in width and have a 2.54 mm distance between the two pins. You can find the pin type data sheet here; part number 855-M50-3530342 with the middle pin removed. The corresponding header for cable connection can be found here; part number 855-M50-3030342 with the middle pin removed.
Based on this information, you can design your own cables or solder your PCB on top of the valve pins.
memetis offers an embedded ECU that allows controlling either a single NC valve or a bistable valve, and is meant to be soldered directly onto your PCB. It has a small footprint of 17 mm x 19 mm and offers I2C communication that works with your microcontroller or Raspberry Pi. Click here to view the info sheet.
Do you need electronics to operate multiple valves simultaneously? Then the memetis ECU-I is the right choice for you! Choose the unit for up to 8-channel control or up to 16-channel control. The dimensions are limited to a maximum of 25.3 mm x 51.3 mm and communication is via USB-C. Click here to view the complete info sheet.
If you have more than one or few valves in your setup, you can create a spring contact connection to your electronics. We have technical drawings here for this solution as initial inputs to your design.
Here you can find three example circuit schematics to build a constant current source to drive a memetis valve on your own PCB:
If you are in doubt about the eletronic control aspects, please reach out to us via contact@memetis.com!
We also offer custom electronic development that fit perfectly into your setup. Our custom electronics can enable control of your whole fluidic system including pumps, sensors and other fluidic parts, as well as we can implement alternative connections on the valves directly. Don't hesitate to send us an inquiry.