Frequently Asked Questions

This is the first place to look when you have a questions about a Motion Lab Systems product. The answers here are categorized into three separate sections covering:

Hardware Answers:

This section answers questions about Motion Lab Systems hardware products, EMG systems, and preamplifiers etc. Questions about our software applications are answered in the next section below.

What are the connector details for the preamplifiers and event-switches?

Information about the connectors that we use, part numbers and the pin-outs for the various EMG electrodes and event switches are available here.

We use a number of different connectors in our systems and publish full details of the signals on each pin to make it easy for anyone owning a Motion Mab Systems EMG system to repair connectors or connect other equipment to our systems. Please contact us if you need additional information - we are always happy to help customers who have any doubts about repairing sensors or connecting additional equipment.

Do you still support your older (MA100 and MA200) EMG systems?

Yes - both the MA100 and MA200 systems are obsolete but we will continue to provide support for these systems wherever possible. While the original "IOMED" preamplifiers supplied with these systems are no longer available, we continue to offer a range of compatible preamplifiers.

Both the MA100 and MA200 systems are officially "unsupported" but we till maintain some spare parts and circuit boards for these systems's. Please remember that many of the components of the older systems are no longer manufactured so continued support or operation of these EMG systems can not be guaranteed in the future.

Are user manuals and schematics available for obsolete systems?

Yes - complete user manuals for the discontinued MA100 and MA200 EMG systems are available in Adobe PDF format.

The user manuals can be downloaded and printed at your convenience from our web site documentation page.

How can I clean sticky tape adhesive from your preamplifier wires?

We use and recommend Goo Gone - this product is available in most US hardware stores.

Simply pour a little "Goo Gone" onto a clean rag and wipe the preamplifiers casing and the surface of the wires to remove tape and other dirt from the preamplifiers and cables. OSHA Material Safety Data sheets are available from the manufacturer

What signal processing techniques do you use in the EMG signal?

None - Motion Lab Systems does no signal processing beyond low pass filtering to ensure that the data is sampled correctly.

We use EMG preamplifiers of our own design placed directly over the muscle (surface EMG) or very close to the insertion site (indwelling EMG). By paying particular attention to the design and other parameters of the preamplifiers we find that these techniques produce exceptionally clean, wide-band EMG signals that reproduce the signal available at the subject skin surface.

Why do MA300 systems include a Low Pass Filter?

Other EMG systems do not include variable LP filters. An EMG system without a variable Low Pass filter must always produce signals at the full bandwidth of the system.

The Nyquist data sampling theorem states that you must sample any signal at a rate that is at least twice as fast as the highest frequency component that can be present in the raw signal. Thus, if you use a systems with (for example) a maximum EMG signal response of 1,000Hz then you must always sample the data at a rate that is at least 2,000 samples per second! The Low Pass filter that is built into our EMG systems allows the user to limit the signal bandwidth under investigation to as low as 350Hz or as high as 2,000Hz so that the data sampling rates can be optimized for various situations and data collection capabilities.

Software Answers:
Why do I have to enter the registration details every time that I run MLS software?

This is because of a security feature in some operating systems. Your computer administrator can make changes to the computer registry to prevent this.

Log into the machine with administrator privileges and run c:\winnt\system32\regedt32.exe to start the registry editor. Locate the HKEY_LOCAL_MACHINE in the Local Machine window. Locate the SOFTWARE key and expand it. Locate the MLS key and highlight it - select the Security option - this causes a drop menu to appear with three options - select the Permissions option. This will open the Registry Permissions dialog window. Select the "Everyone" permission and change it from "Special Access" to "Full Control" or create a permission for "Domain Users" with the "Full Control" access rights.

What are Motion Lab Systems software license conditions?

Motion Lab Systems licenses all its software by "Site License" - this means that you purchase a single copy of the software and that this copy used at the "Site" on any computer that you normally use.

There's no need to purchase additional copies of the software if you buy a new computer for the lab and even more importantly, no hardware keys (dongles) to lose, mislay or get stolen.

How do I get an Evaluation Copy of a program?

Easy - simply download the software image from our web site downloads page and place it in a temporary directory on your computer.

The downloaded file is a full installation image so you can simply run the file to install the software - each software package includes an "uninstall" feature that allows you to completely remove the software if you wish.

Do I have to register the Evaluation software?

No - we have tried to make all of the evaluation versions of our software perform in a way that makes them useful to the casual user and allow you to test run the program before you buy it.

All of our applications are available in evaluation versions that can be downloaded from our web site.

How does Registration work?

When you are ready to purchase a software license you will need to provide us with a couple of phrases that identify your location. This will usually be your name (or the name of the laboratory), and the organization that is purchasing the software.

We will then use this information to generate a unique registration key that will allow the software to operate without any restrictions. We send you the key upon receipt of a purchase order or payment for the software.

I loaded the software on a laptop - can I use it outside work?

Yes, provided that you work or are associated in some meaningful way with the original licensed user.

Motion Lab Systems software licence conditions allow you to use the software fairly without any onerous conditions or restrictions.

Can I take a registered version to a different laboratory?

No - the software is licensed for use in one location so you are breaking our license conditions.

Each time the software runs it will display the original license details so that it will be obvious which location originally licensed the software. This will embarrass both you and the people who originally licence the software.

The software reports an application error when I exit the application.

This is a security feature with newer operating systems where registry values have permission attributes. The administrator can fix it as follows:

Log into the machine with administrator privileges and run c:\winnt\system32\regedt32.exe to start the registry editor. Locate the HKEY_LOCAL_MACHINE in the Local Machine window. Locate the SOFTWARE key and expand it. Locate the MLS key and highlight it - select the Security option - this causes a drop menu to appear with three options - select the Permissions option. This will open the Registry Permissions dialog window. Select the "Everyone" permission and change it from "Special Access" to "Full Control" or create a permission for "Domain Users" with the "Full Control" access rights.

Does the software work on Windows NT, Windows 2000, Windows XP and Vista?

Yes - all our software is tested and written to function correctly on any 32-bit Microsoft operating system. The only known issues are documented on this page and involve the creation of registry permissions.

Log into the machine with administrator privileges and run c:\winnt\system32\regedt32.exe to start the registry editor. Locate the HKEY_LOCAL_MACHINE in the Local Machine window. Locate the SOFTWARE key and expand it. Locate the MLS key and highlight it - select the Security option - this causes a drop menu to appear with three options - select the Permissions option. This will open the Registry Permissions dialog window. Select the "Everyone" permission and change it from "Special Access" to "Full Control" or create a permission for "Domain Users" with the "Full Control" access rights.

I have installed the C3dEditor but can not edit LOCKED parameters?

This feature is disabled by default but can be enabled for a session by checking a box in the General Options. It can be permanently enabled via the following registry script:

REGEDIT4 [HKEY_LOCAL_MACHINE\SOFTWARE\MLS\C3dEditor] "LockedEdit"="True" We suggest that you read the manual carefully and thoroughly understand the C3D format before you enable LOCKED parameter editing.

How do I get the latest copy of your software?

All Motion Lab Systems applications can be downloaded for installation on your system. If you are a registered user then the downloaded program will automatically update your system.

If you are not a registered user then the program will run as an evaluation copy. When any Motion Labs software is installed you will find a link in the Motion Lab Systems Utilities group called Check for Updates - running this link will automatically download the latest software version.

Do you have any free or open source programs?

Yes we do - we have written several applications that we provide free of charge. In addition, all of our evaluation software packages are free and many of them perform useful functions even if you decide not to purchase the software.

Sometime we will issue beta releases of a new application - all beta testers receive a copy of the final released version free of charge - please contact us if you would like to be part of our beta test team.

What operating system do I need to use this software?

A recent copy of Microsoft Windows or an emulator such as WINE running on Linux or FreeBSD.

All Motion Lab Systems programs are written using Microsoft C++ and complied to run on any 32-bit Windows operating systems.

I am having problems editing database records in VCM

Some EMG4VCM users have had problems editing the VCM database records within Vicon Clinical Manager - the symptom is that the database record opens correctly but that VCM crashes with a General Protection Fault when the edited record is closed. This is a common problem with the 1.37 version of VCM.

Motion Lab Systems applications do not edit the VCM database as they open it for read operations only. The problem appears to be related to a bug within VCM that fails to handle the "Short Date Style" correctly when the Regional Settings in the Control Panel are set to mm/dd/yyyy. The work-around for this issue is to always set the Short Date Style to m/d/yy - please contact Oxford Metrics Customer Support for further information about the resolution of this issue. Note that users must enter 2000 for all dates when editing VCM database records.

What references do you use for the EMG normal data in the EMG Analysis and ReportGenerator applications?

The EMG normal activity data is based on numbers that have been extracted from various publications and graphs from a wide variety of sources.

The VCM and OrthoTrak numbers are derived from files supplied with those applications. The 1 through 7 year old information is based on data originally published by Sutherland. The user can edit any of the normal timing information supplied with the EMG Analysis and ReportGenerator applications so it's easy to create a "Lab Specific" normal reference or edit any existing value.

How much faster is the licensed version of the C3Dserver than the free version?

The free demonstration version of the C3Dserver inserts a small delay (about 5ms) after each C3Dserver function - this delay is removed in the licensed version of the C3Dserver.

As a result, the difference in execution speed between the free version and the licensed version depends on the way that your program uses the C3Dserver functions - for example, let us consider two programs written to use the C3Dserver - both execute in 20 seconds using the demonstration version. Program 1 opens a C3D file, reads a number of parameters and performs a complex calculation before updating the parameters and closing the C3D file. This program calls the C3Dserver 80 times so using the licensed version of the C3Dserver will reduce the execution time by 400ms (80*5ms) - the program will run in 19.6 seconds using the licensed version of the C3Dserver. Program 2 opens a C3D file, reads some parameters and then reads 900 frames of data, performs a simple filter operation on the data and rewrites the 900 frames back to the C3D file and updates the parameter block before closing the file. This program calls the C3Dserver 3800 times so using the licensed version will reduce the execution time by 19 seconds (3800 * 5ms) - this program will run in 1 second using the licensed version of the C3Dserver!

I get a message that "Windaq/Lite cannot record faster than 240 sample per second."

You have installed the Windaq/Lite version of the software which is supplied free of charge with the MA-720 ADC system for EMG monitoring use.

To record EMG data you must remove the Windaq/lite software and reinstall Windaq, selecting the Windaq/Pro version. This requires a software license number (normally an 8 digit number that is supplied when you purchase Windaq/Pro) that must be entered when you install the software. If you are not prompted for this number then you will install the Lite version of the software.

Electromyography Answers:

This section of the FAQ attempts to provide answers to questions about EMG data quality - it does not provide information about the interpretation of EMG data as there are plenty of very good books on this subject.

How do I set up the Windaq/Pro software to record EMG data?

You need to make sure that the Windaq/Pro software is sampling the data fast enough - this is controlled by two settings:

Edit:Preferances:Maximum Sample Rate needs to be set to the highest rate that you are likely to need - somewhere in the 50000 to 80000 range works well in most cases. For example, if you are recording 10 channels of EMG + 2 event switch channels then this works out at a per channel sample rate of 50000/12 (just a bit over 4,000 samples per channel). Edit:Sample Rate can now be set to the actual rate that you want to capture data at - this can be anything up to the Maximum Sample Rate that you set above. This rate (like the maximum rate) is the overall throughput rate for the ADC so you count up the number of channels that you are collecting from (we'll assume four channels for this example) and multiply it by the signal bandwidth that you use (controlled by the Bandwidth switch on the BPU - let's assume you have set this to #6 or 500Hz) - then double the result thus ... 4 * 500 * 2 = 4,000 - any sample rate that is greater than 4000 will produce a good EMG recording. Once you have set the sample rates and channel selections you can make the software default to using these settings each time that you start up via the File:Save Default Setup option.

What are the EMG signal levels on the human body in microvolts?

The signal level that can be detected on the surface of the body depends on many different factors.

In our experience the detected signals can range from a few uV to several mV, depending on the strength of the contraction and the position of the sensors relative to the muscle, etc.

I have an MA100 EMG system - can I use it for fine wire studies?

We recommend that you upgrade to a new MA300 system and offer substantial discounts on new systems to existing users. However, it is possible to use fine wire electrodes with the MA100. These instructions assume that you are using standard MA-110 electrodes:

Place the MA100 preamplifier close to the insertion site with the three stainless steel electrodes up (i.e. the back of the electrode on the subjects skin surface). Assuming that you are using a common bi-polar fine wire electrode then you would connect the two fine wires to the outer two stainless pads (these are the preamplifier inputs). If you remove the insulation from the fine wire then you can often simply tape the un-insulated wire ends directly to the preamplifier. The center stainless steel electrode disk must then be connected to the subjects skin surface to provide a ground reference point - alternatively you can use a separate ground electrode attached to the MA100 back-pack case (the MA100 does not provide a separate ground reference - however all MA300 systems include a ground reference connector as standard using a normal DIN electrode connector). Many people have reported good results by simply taping the fine wire to the outer two pads while leaving the center pad uncovered. If the outer two pads are completely insulated by the tape then it's possible to turn the preamplifier over and attach it to the subjects skin in such a way that the center ground reference electrode is in contact with the subject. It is also possible to unscrew the three stainless steel disks on the preamplifier and replace them with thumbscrews or springs although this is not recommended as it is easy to damage the preamplifiers.