by harald » Thu Sep 02, 2010 23:09 pm
Sailing Anarchyssä on hyvä ketju koskien Nexus-järjestelmän kalibroinnista;
http://forums.sailinganarchy.com/index. ... pic=109987
Woolfy@anarchy wrote:
Guy from Detroit first.... basically there are two stages to the calibration work you need to do. Firstly there is the basic "standard" calibration proceedures, these can be done using the NX2 Multi display, you'll need the manual and the calibration certificate, neither of which you seem to have, based on what you're saying. So stage 1 is to go on line
www.nexusmarine.se and in the support section you'll find all the manuals for old and current kit, download whichever ones you need. The calibration certificate is a bit more tricky, you'll need to supply me with the serial number of the MHU, this is on a sticker that is attached to the arm of the MHU itself, give me that and I'll get a copy for you. In production every single MHU we make is individually calibrated on a special rig with correction factors being calculated for each 45 degree sector, these correction values need to be loaded into the server, and this is done either using one of the displays or the race software. Having got those loaded then using the manual get all the other standard (those in the manual) calibrations done as well. When I say all I do mean ALL, speed, compass and wind need to be completed and accurate if race usable wind information is to be displayed, have the speed or compass information slightly out and calculations for wind data will reflect these inaccuracies and give you duff information. DO NOT use the race software for doing the compass calibrations it's got a bug and won't store the corrections properly, we'll get this sorted in due course, for the time being just do the compass swings, checks and alignments using a display as your controller.
This then brings you to the second stage of the calibration process. Pogen this has some relavence to you. (Incidentally I presume you're refering to function C54 when calibrating using a NX2 Multi display when you refer to the "wind calibration factor" beiing set to 1.00, if this is the case then you are correct to have changed it to 1.50 if you have a single fin MHU, if it's a twin fin transducer this number should be 1.70)
Whilst you're on line to the Nexus website finding your manuals you should also download the NX2 Race Software (Ver 1.07), there are a few versions on the site dependant on what your computer system has (windows vista and 7 need a different package downloaded) you will also need to download the "RS232-USB Driver" software as well if you haven't already got that on your computer.
With this you can now do the "fine tweaking" calibrations, the principal one you need to do is the "Advanced Speed" calibration, you should have already doen the basic speed cal earlier (I always use the Race Software to do this rather than the NX2 multi display as I told you to earlier, it's actually a lot easier, so use it too) so now all you need to do is the advanced speed calibration....this is as Jim describes it, you sail along on each of the tacks for a couple of minutes then bear away onto a run for a couple of minutes and you're done. This is probably the most important bit of calibration you can do, it takes out the inconsistancies caused by the variations in the speed of the water flow that occurs when a boat is heeled over i.e. you will no longer appear (according to the log at least) to be going faster on one tack than the other....unless of course you are!
You should now find that if you've done everything correctly, there will however still be a few anomalies as wind sheer, updraft, angle of heel etc will come into play. As these vary minutely from minute to minute and enormously over a range of wind strengths, direction, sail configaration etc there is not really any magic bullet to factor these in, high quality correctly operated tactical software goes a hell of a long way towards this but even that is never quite perfect all the time. Incorparated into the NX2 Race software is an additional wind calibration feature, the T.R.U.E. feature, this is very easy to use, actually pretty accurate and more importantly takes very little time and can be completed whilst actually out racing. It basically involves logging data for a minute or so on each tack then applying the corrections with a button press, as conditions change (wind strength, sail configaration etc) during the course of the day then the process can be repeated to ensure that corrections are correct for the current conditions. Not everyone uses this function, it's actually pretty good but by the time people are getting that fussy about wind data they're usually using tactical software such as Expedition, which is better, although you do have to pay for it!
Sailing Anarchyssä on hyvä ketju koskien Nexus-järjestelmän kalibroinnista;
http://forums.sailinganarchy.com/index.php?showtopic=109987
[quote="Woolfy@anarchy"]
Guy from Detroit first.... basically there are two stages to the calibration work you need to do. Firstly there is the basic "standard" calibration proceedures, these can be done using the NX2 Multi display, you'll need the manual and the calibration certificate, neither of which you seem to have, based on what you're saying. So stage 1 is to go on line www.nexusmarine.se and in the support section you'll find all the manuals for old and current kit, download whichever ones you need. The calibration certificate is a bit more tricky, you'll need to supply me with the serial number of the MHU, this is on a sticker that is attached to the arm of the MHU itself, give me that and I'll get a copy for you. In production every single MHU we make is individually calibrated on a special rig with correction factors being calculated for each 45 degree sector, these correction values need to be loaded into the server, and this is done either using one of the displays or the race software. Having got those loaded then using the manual get all the other standard (those in the manual) calibrations done as well. When I say all I do mean ALL, speed, compass and wind need to be completed and accurate if race usable wind information is to be displayed, have the speed or compass information slightly out and calculations for wind data will reflect these inaccuracies and give you duff information. DO NOT use the race software for doing the compass calibrations it's got a bug and won't store the corrections properly, we'll get this sorted in due course, for the time being just do the compass swings, checks and alignments using a display as your controller.
This then brings you to the second stage of the calibration process. Pogen this has some relavence to you. (Incidentally I presume you're refering to function C54 when calibrating using a NX2 Multi display when you refer to the "wind calibration factor" beiing set to 1.00, if this is the case then you are correct to have changed it to 1.50 if you have a single fin MHU, if it's a twin fin transducer this number should be 1.70)
Whilst you're on line to the Nexus website finding your manuals you should also download the NX2 Race Software (Ver 1.07), there are a few versions on the site dependant on what your computer system has (windows vista and 7 need a different package downloaded) you will also need to download the "RS232-USB Driver" software as well if you haven't already got that on your computer.
With this you can now do the "fine tweaking" calibrations, the principal one you need to do is the "Advanced Speed" calibration, you should have already doen the basic speed cal earlier (I always use the Race Software to do this rather than the NX2 multi display as I told you to earlier, it's actually a lot easier, so use it too) so now all you need to do is the advanced speed calibration....this is as Jim describes it, you sail along on each of the tacks for a couple of minutes then bear away onto a run for a couple of minutes and you're done. This is probably the most important bit of calibration you can do, it takes out the inconsistancies caused by the variations in the speed of the water flow that occurs when a boat is heeled over i.e. you will no longer appear (according to the log at least) to be going faster on one tack than the other....unless of course you are!
You should now find that if you've done everything correctly, there will however still be a few anomalies as wind sheer, updraft, angle of heel etc will come into play. As these vary minutely from minute to minute and enormously over a range of wind strengths, direction, sail configaration etc there is not really any magic bullet to factor these in, high quality correctly operated tactical software goes a hell of a long way towards this but even that is never quite perfect all the time. Incorparated into the NX2 Race software is an additional wind calibration feature, the T.R.U.E. feature, this is very easy to use, actually pretty accurate and more importantly takes very little time and can be completed whilst actually out racing. It basically involves logging data for a minute or so on each tack then applying the corrections with a button press, as conditions change (wind strength, sail configaration etc) during the course of the day then the process can be repeated to ensure that corrections are correct for the current conditions. Not everyone uses this function, it's actually pretty good but by the time people are getting that fussy about wind data they're usually using tactical software such as Expedition, which is better, although you do have to pay for it! :P [/quote]