<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:'times new roman', 'new york', times, serif;font-size:12pt"><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; ">Good day, Dr. Wilhelm!</div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; "><br></div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; ">First of all, I want to say that I am very pleased with the response mail I have received from you! Your response inspires a high level of professionalism and I appreciate the honesty in it, which is a thing I respect. Even though TestManager is an "old house" and written some time ago, I can say firmly: <i>it does the job!</i>, because an old shed is always bound to have a lot of useful tools lying around.</div><div style="font-family: 'times new roman', 'new york', times, serif;
font-size: 12pt; ">About the translation of the Documentation, I have here an English translation but it seems to be simpler than the German documentation I found on your website. It would be nice to have a more in-depth knowledge about this software because I am using it quite often. Thank you!</div><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; ">Another thing I've noticed since the last time I wrote is that this next example tends to happen: I select Data Transfer pane, I input all of my desired options (Sample Rate, Accuracy and Buffer size for each channel) , then I close the Data Transfer dialog box; after some time, I want to re-set some options on one or two channels in the Data Transfer dialog, but when I open it again, all of my previous settings are ...more or less gone. They are reset somehow . Then I have to input again the sample rate, accuracy and buffer size for all my channels which is a bit of a
task.</div><div><font class="Apple-style-span" face="arial, helvetica, sans-serif" size="2">All of the other questions I understood your answer. I am now looking forward to getting started with DLS and see what it is about. My TestManager version is : 3.4.20e, Revision 149.</font></div><div><font class="Apple-style-span" face="arial, helvetica, sans-serif" size="2"><br></font></div><div><font class="Apple-style-span" face="arial, helvetica, sans-serif" size="2">I wish you a good day!</font></div><div><font class="Apple-style-span" face="arial, helvetica, sans-serif" size="2">Kind regards,</font></div><div><font class="Apple-style-span" face="arial, helvetica, sans-serif" size="2">Alex Marton<br></font><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; "><br><div style="font-family:arial, helvetica, sans-serif;font-size:13px"><font size="2" face="Tahoma"><hr size="1"><b><span style="font-weight: bold;">From:</span></b>
Dr.-Ing. Wilhelm Hagemeister <hm@igh-essen.com><br><b><span style="font-weight: bold;">To:</span></b> etherlab-users@etherlab.org; martonalex@yahoo.com<br><b><span style="font-weight: bold;">Sent:</span></b> Mon, December 20, 2010 12:29:33 AM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [etherlab-users] Data Transfer options in TestManager<br></font><br> Hello Alex,<br><br>a bit of background to the testmanager. Actually I am the programmer of<br>the testmanager and of course, in reference to your earlier email, I<br>agree that there is a lot of documentation missing and also some<br>features are not really clear or self explanatory to the user. Actually<br>we are working on an improved version of the documentation and I will<br>make sure you get the english version as one of the first persons. But I<br>can't promise when this will be ready.<br><br>The testmanager is written in Delphi 5 ! and parts of the software are<br>already
12 years old and if you ask me where nobody can hear us, I would<br>not code it this days the way I designed it years ago.<br><br>It is a bit like an old house with a lot of sheds build around it. As a<br>user you might see that also, when you find out that some features are<br>missing which you can expect from a modern piece of software. A couple<br>of years ago we started to write a portable version in C++ and the<br>QT-library which compiles under Linux and Windows but we just don't have<br>the resources right now to bring this job to and usable state.<br><br>Anyway the testmanager does his job reliably and still gets bug fixed...<br><br>Now to your questions... find my annotations below:<br><br>Am 17.12.2010 12:03, schrieb Alex C. Marton:<br>> Dear friends at EtherLab community,<br>> <br>> Thank you for giving me another chance! This time I will not let you down!<br>> I have been using TestManager in a real industrial hydraulics
application for a <br>> while now. I generally had good results with it, but now I wish to change my <br>> sampling rate and also the accuracy of the data captured (I was using 1000 Hz @ <br>> 2 accuracy which is too high). I have tried doing so but I see the following <br>> observations about the options that I can set/choose:<br>> a. the sampling rate cannot be any value I wish to choose for all channels. I <br>> tried sampling @ 300, 450, 720 Hz and always TestManager rounds off my value to <br>> a different one, a calculated one I see, so it must implement a formula I do not <br>> know about. I would like to sample @ 10 Hz in my application which I see it can <br>> handle, but I do not know why an intermediate value for the sample rate is not <br>> possible.<br><br>We decided to make the data transfer rate from the realtime process to<br>the testmanger a multiple of the base tick.<br>Actually the downsampling
algorithm just takes the n-th value of the<br>channel data. So with 1kHz base tick you can realize 500Hz, 250Hz,<br>200Hz, 166.666 Hz, 125Hz and so on but not 300,450 or 720Hz because they<br>are not a divider of 1000Hz.<br><br><br>> b. The data accuracy I choose is not "recorded" while using the Scope. I tried <br>> inputting different values from 1 to 9 and then verifying the .txt files <br>> generated by exporting the acquired data in a Matlab format. Most of the time I <br>> get values with 16 digits after the "." in the number. Other times I get values <br>> with only 2 decimal points. I see the files are a lot larger when having 16 <br>> digit accuracy than when I have 2 digit accuracy and I would like to have 4 <br>> accuracy, because space is an issue for me.<br><br>The accuracy only has an effect on the data stream from the process to<br>the testmanager. Because the transport of the process values to
the<br>testmanager is in formated text - one can discuss on that choice but a<br>binary format is also available but not used in testmanger - it is<br>useful in two ways.<br>1. it reduces the data rate when set to low values.<br>As an example: 123.34456465665,123.4567678790854,123.56778989043213132<br>takes more bandwith to transport than 123.34,123.45,123.56.<br><br>2. it enhances accuracy when dealing with small values:<br>0.0000010123,0.0000010232,0.0000010345,0.0000010123 is relatively more<br>accurate than 0.000001,0.000001,0.000001,0.000001<br><br>Internally all channel data are represented in double precision so for<br>exporting from the scope the accuracy has no direct affect on the saved<br>file size.<br><br>For sampling large amount of data you better use the "dls" program which<br>also comes with the EtherLab bundle. It brings effective data<br>compression algorithms with it. The scope in the testmanager was only<br>intended to record
over a "short" period of time and I didn't optimize<br>the export for file size. Also the sampled data gets stored and hold in<br>RAM so if sampling over a long period of time with the testmanager you<br>might run out of memory.<br><br><br><br>> c. What is the effect of a high "Buffer Size/s" in the Data Transfer option <br>> pane? I already know the effect of having it too small (the graphics of the <br>> signals are limited), but I would like to know what is the drawback of having it <br>> too large? One thing I notice is the Data Rate going very high. What is an <br>> optimal value for that to input?<br><br>Recieved data gets stored in a ring buffer. And the size of the ring<br>buffer is what you adjust here. High values with high sample rates will<br>use a lot of ram. The ring buffer prevents loss of data, I thought years<br>ago, not taking into account that the TCP/IP transport mechanism has a<br>buffer as well which might be
sufficient. The scrolling instruments<br>display data directly from the ring buffer so they don't bring their own<br>buffer. If you make the buffer shorter than the time axis of this<br>instruments the signals will be limited as you already worked out. The<br>buffer size should have no influence on the data rate!! A value of 1 sec<br>is no problem is you don't have scrolling instruments, otherwise you<br>have to set the buffer size at least to the time interval of these<br>instruments for the channels you display there.<br><br><br>> My Data Rate I read here right now is 70-80 Kb/s @ 300 Hz. Does this have an <br>> effect on the topics I've written so far?<br><br>For just visualization I use 10Hz update rate, for analysis I transfer<br>as quick as is necessary; just keep an eye on how much the testmanager<br>and also the etherlab_buddy loads your machines. Also the max. bandwidth<br>of your network might be an issue then.<br><br>Have fun with
the testmanager<br><br>which version are you using?<br><br>Regards Wilhelm.<br></div></div><div style="position: fixed; font-family: 'times new roman', 'new york', times, serif; font-size: 12pt; "></div> </div></div><br>
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