More precise control thanks to integrated pressure measurement

The precise pressure-controlled dosing of liquids in a microfluidic system is a precondition for exact pressure measurement and requires high media resistance of the devices used. Only the interaction of precision pumps and high-precision pressure sensors enables fine dosing and process control at the highest level. With our new external pressure sensors we raise your flow system to a new level.

Individually adaptable and extremely media-resistant

The sensors are not only suitable for high-precision measurements, but can also be adapted to a wide variety of requirements. The heart of the extremely compact pressure measuring module is a highly media-resistant ceramic sensor that can be designed for pressure ranges up to 200 bar.

In order to optimally adapt the chemical resistance of the pressure measuring module to the media used, all housing parts and sealing elements that are in direct contact with the medium can be offered in different material versions. The electrical interface can be designed for convenient integration.

We are pleased to announce the first release of the QmixElements software in 2019. With this release we extend the functional range of the CETONI devices by new features, functions and we supplement the software with many useful details or improve existing functions. Highlight of the new QmixElements version v20190108 is the improved graphical user interface with the new Advanced Docking System.

In the previous QmixElements software there was a central area for switching workspaces. Individual tool windows could be freely arranged and moved around this central area. So it was possible to customize the graphical user interface to a limited extent.

However, the individual workspaces displayed in the central area could not be moved and only one workspace was visible at a time. For example, one could work either in the user interface of the neMESYS pumps, or in the positioning map for the rotAXYS or one could show the graphical logger. A simultaneous display was not possible up to now.

Dock everywhere – no central widget

In the new QmixElements software this limitation no longer exists. Due to the new advanced docking system there is no longer a central workspace, but only single views (windows) which can be positioned freely in the graphical user interface or can be detached from it.

You can dock all views at any edge of the main window or in any other view – so you can dock virtually anywhere and move any view to any position. Markers make it easy to see where you can insert a view.

Detach views as separate windows – perfect for multi-monitor use

Not only can you move all views to new positions in the main window, but you can also detach the individual views completely from the application window and move them as a stand-alone window. This allows you, for example, to move each individual view to a different monitor. This ensures that you always keep an eye on important information and make optimum use of the available screen space.

Individual views can be “docked” to any position not only in the main window of the application, but in every window and every individual view of the application. This allows you to distribute all views across multiple windows or even across multiple monitors.

Moving Multiple Views Simultaneously

You can not only move individual views and detach them from the user interface, but also complete view groups. If you have grouped several views in tabs, you can remove the entire view group by clicking on the title bar of the group and pulling it out of its position. This allows you to quickly customize even complex layouts.

Perspectives – fast switching of the entire user interface

A certain layout of views that is perfectly suited for a particular application or user may be less suited for other tasks or other users. The new graphical user interface helps you to switch the complete layout with just one mouse click and to completely change the arrangement of views and windows in a second. The software offers so-called “perspectives” for this purpose. A perspective is nothing more than a certain layout of views with a fixed name. This means that if you have found the perfect configuration of views for a certain task, simply save this configuration under a name as a perspective.

Other perspectives can be created for other tasks and other users. Later, you can simply select a perspective from the perspective menu to quickly switch the interface layout for a new task.

The video on our youtube channel gives you a first impression of what is possible with the new advanced docking system of the QmixElements software.

Many applications require a continuous media supply independent from the syringe volume. For such cases we have created now a simple and effective solution of a compact valve unit as an ideal supplement to our neMESYS low and medium pressure modules. In combination with a novelty in the configuration dialog of the continuous flow mode in our QmixElements software, the pressure controlled switching, the continuous dosing can be realized easily and quickly. For this purpose, two syringe pumps equipped with this novel valve unit are optimally synchronized in the switching behaviour, whereby a smooth transition is achieved.

Product details

The compact combination of two separate 2/2-way valves and a pressure sensor (up to max. 10 bar) enables you to set up a continuous pumping procedure quick and conveniently – whether for our low-pressure or mid pressure syringe pumps.

 

The sophisticated valve unit combines two 2/2-way valves and one pressure sensor per module in one compact component. The less space consuming and compact design and practical arrangement allows quick and comfortable access to the fluidic interface (1/4”-28 UNF inlet/outlet).

On the input side, the selected syringe is screwed directly into the valve unit and is thus safely fixed on the module. The fluidic interface for application and reservoir are on the opposite side and are labeled with RES and APP. Visual user support during operation is guaranteed by the LEDs under the respective fluid connection which indicates the current switching position. PPS, FKM and Al2O3 are installed in the valve unit as wetted parts.

Indication of the valve switching position (application / reservoir) by LEDs
Indication of the valve switching position (application / reservoir) by LEDs

For the continuous operation, connect the two RES connections to your reservoir (yellow in the picture) and the APP connections of both pumps to your application (blue in the picture), for example via a T-piece. The valve unit has three fluidic connections with ¼”-28 UNF female thread.

The following overview illustrates how three previously separate products, two valves and one pressure sensor, are now compactly and clearly combined in one product.

Specification

• 3/4-way valve (10 bar max.)
• one integrated pressure sensor (20 bar)
• wetted parts: PPS, FKM, AI2O3
• for neMESYS Low and Mid Pressure Syringe Pumps

You can find detailed information and technical details about our new 3/4-way Contiflow Valve on our product page. We are happy to support you for the realisation of your individual set-up for continuous media supply.

With the new Python integration for the Qmix SDK you can develop small applications in the shortest time, automate certain dosing processes or realize your own analyses. The main advantage of Python is its ease of programming, which significantly reduces the time required to develop, debug and maintain the code. In the following example we show you how easy and fast you can implement an application with Python and the Qmix SDK.

Installation

To install, simply use the Qmix SDK installation package for Windows. The SDK will be installed in a folder of your choice.

Integration

To include the Qmix SDK in your Python script you have to add the path containing the Qmix SDK modules to the module search path. In order for Python to load the shared libraries (DLLs) of the SDK, you must then add the path containing the DLLs to the Windows search path. All details are also available in the online documentation.

import sys
import os
QMIXSDK_DIR = "C:/temp/QmixSDK-64bit_20180626"
sys.path.append(QMIXSDK_DIR + "/lib/python")
os.environ['PATH'] += os.pathsep + QMIXSDK_DIR

 

Now you can import the modules of the Qmix SDK Python integration.

from qmixsdk import qmixbus
from qmixsdk import qmixpump

 

The first Python application

Now you can start developing your first application. The following program shows a small example. First a bus object is created, initialized with the path to a device configuration and then the communication is started. Then we create a pump object and connect it to the first pump in the SDK – device index 0. As a test we print the name of the pump with the print function.

def main():
"""
A small example that shows how to use the Qmix SDK for Python
"""
bus = qmixbus.Bus()
bus.open("testconfig_qmixsdk", "")
bus.start()
pump = qmixpump.Pump()
pump.lookup_by_device_index(0)
print(pump.get_device_name())

 

In the next step we perform a reference run with the calibrate function to determine the zero position of the pump. Before the reference run, we clear any remaining errors (clear_fault) and enable the pump (enable). With the help of a timeout timer we wait until the calibration is finished.

pump.clear_fault()
pump.enable(True)
pump.calibrate()
timeout_timer = qmixbus.PollingTimer(10000)
result = timeout_timer.wait_until(pump.is_calibration_finished, True)
print(result)

 

The pump is now initialized and we can start dosing. For this we set the units for volume and flow rate to milliliter and milliliter per second. As a test we will output the unit for the flow with the print function. Then we configure the syringe to be used. We use a syringe with 1 mm inner diameter and 60 mm plunger stroke. In line 41 we start the aspiration (aspirate) of 0.02 ml with a flow rate of 0.004 ml/s. With a timeout timer we wait again until the dosage is finished.

pump.set_volume_unit(UnitPrefix.milli, VolumeUnit.litres)
pump.set_flow_unit(UnitPrefix.milli, VolumeUnit.litres, TimeUnit.per_second)
print(pump.get_flow_unit()
pump.set_syringe_param(1, 60)
print(pump.get_syringe_param())
print(pump.get_volume_max())
print(pump.get_flow_rate_max())
pump.aspirate(0.02, 0.004)
timeout_timer.set_period(10000)
result = timeout_timer.wait_until(pump.is_pumping, False)
print(result)

 

At the end of the program we stop the communication and call the close function of the bus object to release all resources again.

bus.stop()
bus.close()

 

We hope you got a small impression of how powerful and simple the Qmix SDK for Python is. You can download the Python example from this blog post here.