---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 09/09/15: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:38 AM - Re: Pitot Heat Ground (JDA_BTR) 2. 05:03 AM - Engine Starter Stalling (todehnal) 3. 05:46 AM - Re: Engine Starter Stalling (Charlie England) 4. 07:11 AM - Re: Re: Pitot Heat Ground (Kelly McMullen) 5. 07:31 AM - Re: Active VOR antenna () 6. 07:31 AM - Re: Engine Starter Stalling (Kelly McMullen) 7. 07:50 AM - Fuse links (John Tipton) 8. 09:06 AM - Re: Engine Starter Stalling (todehnal) 9. 09:48 AM - Re: Re: Engine Starter Stalling (Charlie England) 10. 10:05 AM - Re: Engine Starter Stalling (Robert L. Nuckolls, III) 11. 10:07 AM - Re: Pitot Heat Ground (Robert L. Nuckolls, III) 12. 11:16 AM - Re: Pitot Heat Ground (Lyle Peterson) 13. 11:52 AM - Re: Pitot Heat Ground (Ryan Brown) 14. 11:54 AM - Re: Re: Engine Starter Stalling (Tim Andres) ________________________________ Message 1 _____________________________________ Time: 04:38:19 AM PST US Subject: AeroElectric-List: Re: Pitot Heat Ground From: "JDA_BTR" I spoke with a knowledgeable person at Dynon and was told that the MOSFET power transistor in the controller uses the case for a heat sink and thus is grounded to same; so the ground to the chassis is by design and necessary. It will also be low impedance in this configuration. In a metal airplane even if a wire is carried back to the battery most if not all of the current will pass to the mounting points of the controller box; so grounding the box to the airframe locally will make as much sense as carrying a wire back to the battery. There won't be a way to make a balanced wire run for the pitot heat controller. I could mount the controller in the fuselage and run the actual pitot wires balanced out to the heater. Will have to consider that; but I'm thinking now to just wire it up and if the magnetometer is affected (likely) then I'll remote it to another location, or relocate the ADAHRS/magnetometer. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=446911#446911 ________________________________ Message 2 _____________________________________ Time: 05:03:05 AM PST US Subject: AeroElectric-List: Engine Starter Stalling From: "todehnal" Hi Guys, New kid on the block, and I am looking for some advice. I have been having starter stall on cold starts. It will stop the prop a couple of times, and then spin up and start fine. I have been chasing this for a couple of months now. By the way, this is a Rotax powered RV-12. I know that when this happens the starter solenoid chatters. I can hear it. This chatter is caused by another starter circuit interrupt on the RV-12 called the spar pin relay. This safety device ensures that the removable wings spar pins are fully engaged, then completed the circuit to the start relay. I am now analyzing the battery. I downloaded data from the Dynon skyview, searched the spreadsheet and came up with a chart that shows the battery voltage during a typical start. If someone could take a look at the link below and offer some thoughts about the battery performance, or offer other advice, I would greatly appreciate it. Neat chart, and you can see the compression cycles on the chart. Thanks.........Tom http://i296.photobucket.com/albums/mm182/tomscub/img002_zpsujxtzrle.jpg -------- RV-12 with Skyview Panel built EAB by my wife & I. First Flight: 11/21/13. It's a keeper....Tom Read this topic online here: http://forums.matronics.com/viewtopic.php?p=446912#446912 ________________________________ Message 3 _____________________________________ Time: 05:46:03 AM PST US Subject: Re: AeroElectric-List: Engine Starter Stalling From: Charlie England On Wed, Sep 9, 2015 at 7:01 AM, todehnal wrote: > > Hi Guys, New kid on the block, and I am looking for some advice. I have > been having starter stall on cold starts. It will stop the prop a couple > of times, and then spin up and start fine. I have been chasing this for a > couple of months now. By the way, this is a Rotax powered RV-12. I know > that when this happens the starter solenoid chatters. I can hear it. This > chatter is caused by another starter circuit interrupt on the RV-12 called > the spar pin relay. This safety device ensures that the removable wings > spar pins are fully engaged, then completed the circuit to the start > relay. I am now analyzing the battery. I downloaded data from the Dynon > skyview, searched the spreadsheet and came up with a chart that shows the > battery voltage during a typical start. If someone could take a look at > the link below and offer some thoughts about the battery performance, or > offer other advice, I would greatly appreciate it. Neat chart, and you can > see the compression cycles on! > the chart. Thanks.........Tom > > http://i296.photobucket.com/albums/mm182/tomscub/img002_zpsujxtzrle.jpg > > -------- > RV-12 with Skyview Panel built EAB by my wife & I. > First Flight: 11/21/13. It's a keeper....Tom > > Where does the Dynon measure battery voltage? If it's measuring the voltage between its own B+ & ground terminals, it can't tell the difference between a weak battery and bad connections somewhere in the power circuit. They can be anywhere along the B+ path, or anywhere along the ground path back to the battery. Try monitoring the battery voltage with a separate meter connected directly to the battery terminals (the posts, not the cable terminals on the battery terminals). Watch the meter while cranking the engine, & see how far voltage drops. It's hard to get the time domain resolution on a digital meter that you see on the Dynon graph, so you might try pulling the Dynon fuse, & power the Dynon with a wire directly to the battery B+ terminal so it can see true battery voltage during cranking. Remember to run a ground wire from the Dynon directly to the battery ground terminal also, if you try this. If you see your voltage drops going to ~9-10volts instead of 6-8volts, then you probably have some bad connections somewhere in the circuit. If the battery is truly dropping to 6volts during cranking, then it's either not fully charged, or defective. (Or you've got a bad starter.) ________________________________ Message 4 _____________________________________ Time: 07:11:59 AM PST US Subject: Re: AeroElectric-List: Re: Pitot Heat Ground From: Kelly McMullen IIRC the general guidance is that high current devices like pitot heat and landing lights, nav lights do not need separate ground wire back to grounding block, only sensitive low current electronic devices like radios, intercoms, etc need central grounding. I haven't flown yet, but have the Dynon heated pitot with the controller mounted within 6" of the pitot mast. If you can't mount the combined ADAHRS in the fuselage clear of magnetic influences. they also offer a separate, remote magnetometer that you could mount out near a wing tip. On 9/9/2015 4:32 AM, JDA_BTR wrote: > > I spoke with a knowledgeable person at Dynon and was told that the MOSFET power transistor in the controller uses the case for a heat sink and thus is grounded to same; so the ground to the chassis is by design and necessary. It will also be low impedance in this configuration. In a metal airplane even if a wire is carried back to the battery most if not all of the current will pass to the mounting points of the controller box; so grounding the box to the airframe locally will make as much sense as carrying a wire back to the battery. > > There won't be a way to make a balanced wire run for the pitot heat controller. > > I could mount the controller in the fuselage and run the actual pitot wires balanced out to the heater. Will have to consider that; but I'm thinking now to just wire it up and if the magnetometer is affected (likely) then I'll remote it to another location, or relocate the ADAHRS/magnetometer. > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=446911#446911 > > ________________________________ Message 5 _____________________________________ Time: 07:31:04 AM PST US From: Subject: Re: AeroElectric-List: Active VOR antenna VOR antenna project update: I want to extend a big THANK YOU to all that helped with this project and tell you it was a complete success! We have been progressing through Phase I testing and the non-standard VOL/ILS antenna design is working splendidly. It is being used with a Garmin 650 (internal splitter) and locks onto VOR signals from 100mi @ 10,000=99 and has no problem at all with ILS capture either. It was made from RG-58 coax and a short scrap of 22-AWG wire for the counterpoise per the dimensions below. We are very pleased with it=99s performance and can=99t imagine that a standard antenna would perform any better in this application. Testing will continue to determine if there are any blind or degraded spots or freqs. But for now, mark it up as a successful alternate design! Thanks again! -James Berkut/Race 13 From: Robert L. Nuckolls, III Sent: Thursday, June 04, 2015 5:26 PM Subject: Re: AeroElectric-List: Active VOR antenna Jim, finished one of these and was disappointed in performance. The thing is so tiny that it's hard to troubleshoot, assembled a second just in case. I think the best plan-b for now is to install a quasi-sleeve dipole . . . except that the 'sleeve' is just a piece of wire. I forget how long you said your antenna conduit was, hopefully considerably more than 26". Make the antenna from wire stiff enough to push into the tube on the end of the coax. Wouldn't put a connector in the counterpoise. Just thread it to the ship's interior on installation and tape it sort out of the way. I've got a couple other antenna projects on the bench but some buys waving credit cards have purchased some keyboard/hammer-n-tongs time . . . and I've got a couple of pots boiling for B&C. I'd like to pursue the active antenna experiment. It would be useful to field test the idea in close proximity to transponder and vhf/comm transmitters! In the mean time, let's get your airplane flying. Bob . . . ________________________________ Message 6 _____________________________________ Time: 07:31:12 AM PST US Subject: Re: AeroElectric-List: Engine Starter Stalling From: Kelly McMullen The Dynon system allows the builder to place the voltage sensing lead where ever he/she chooses. Could be where battery plus connects to the bus, could be most anywhere. I don't know where the RV-12 plans call for the connection, but with this aircraft built under EAB rules rather than ELSA, he didn't have to follow the plans. On 9/9/2015 5:44 AM, Charlie England wrote: > > > On Wed, Sep 9, 2015 at 7:01 AM, todehnal > wrote: > > > > > > Where does the Dynon measure battery voltage? If it's measuring the > voltage between its own B+ & ground terminals, it can't tell the > difference between a weak battery and bad connections somewhere in the > power circuit. They can be anywhere along the B+ path, or anywhere > along the ground path back to the battery. > > Try monitoring the battery voltage with a separate meter connected > directly to the battery terminals (the posts, not the cable terminals > on the battery terminals). Watch the meter while cranking the engine, > & see how far voltage drops. It's hard to get the time domain > resolution on a digital meter that you see on the Dynon graph, so you > might try pulling the Dynon fuse, & power the Dynon with a wire > directly to the battery B+ terminal so it can see true battery voltage > during cranking. Remember to run a ground wire from the Dynon directly > to the battery ground terminal also, if you try this. > > If you see your voltage drops going to ~9-10volts instead of 6-8volts, > then you probably have some bad connections somewhere in the circuit. > If the battery is truly dropping to 6volts during cranking, then it's > either not fully charged, or defective. (Or you've got a bad starter.) > http://www.matronics.com/contribution ________________________________ Message 7 _____________________________________ Time: 07:50:02 AM PST US Subject: AeroElectric-List: Fuse links From: John Tipton Hi Guys We will be using a (base) Z11 for our RV9a Q 1 - The only CB's in use (otherwise all fuses) will be the 'ALT FIELD' CB, and a pullable CB for the autopilot, the 'Alt Field' wire is fed with as 'fusable link', does the autopilot feed need the fusable link too (same source, ie main power bus feed, same run length) Q 2 - The Z11 endurance feed, does not have any protection, yet all (I think) other Z figures do have a fuse link feed. Lastly, when making up the fuse links, is it OK to finish off the end covering with 'shrink wrap' or should the covering have 'free air' circulation Regards John ________________________________ Message 8 _____________________________________ Time: 09:06:25 AM PST US Subject: AeroElectric-List: Re: Engine Starter Stalling From: "todehnal" I did build my RV-12 under EAB rules. Pretty sure Dynon is monitoring the voltage at the Avionics Bus, right at the amperage shunt. As far as the starter, I have hooked a +12 volt lead directly to it, and it functions flawlessly. I also have removed, cleaned, and reattached every connection from the battery plus, through the master relay, through the start relay, and starter, and back to the battery ground post, with no change. I guess my real question should be, is it a problem when the active starter voltage dips below 7 volts? Not sure what I should typically be seeing here........Tom -------- RV-12 with Skyview Panel built EAB by my wife & I. First Flight: 11/21/13. It's a keeper....Tom Read this topic online here: http://forums.matronics.com/viewtopic.php?p=446927#446927 ________________________________ Message 9 _____________________________________ Time: 09:48:47 AM PST US Subject: Re: AeroElectric-List: Re: Engine Starter Stalling From: Charlie England On 9/9/2015 11:04 AM, todehnal wrote: > > I did build my RV-12 under EAB rules. Pretty sure Dynon is monitoring the voltage at the Avionics Bus, right at the amperage shunt. As far as the starter, I have hooked a +12 volt lead directly to it, and it functions flawlessly. I also have removed, cleaned, and reattached every connection from the battery plus, through the master relay, through the start relay, and starter, and back to the battery ground post, with no change. I guess my real question should be, is it a problem when the active starter voltage dips below 7 volts? Not sure what I should typically be seeing here........Tom > > -------- > RV-12 with Skyview Panel built EAB by my wife & I. > First Flight: 11/21/13. It's a keeper....Tom > Does that mean that you *started the engine* by hooking a battery lead directly to the starter? Because if you removed the starter & just spun it up with the battery, that doesn't give you much useful info that you didn't already know (that the windings have some continuity and the bearings allow it to turn). If you're monitoring voltage anywhere except at the battery terminals, you really need to know actual battery voltage *at the battery posts* before proceeding further. If it's staying higher than 8-10 volts while cranking, and you're seeing 6 volts at the remote monitoring point, you've got high resistance somewhere in the power circuit between battery & monitoring point. Don't forget that every connection using a terminal on a wire is really *two* connections: the transition in the bolted joint, and the joint between the terminal and the wire itself, whether crimped or soldered. Voltage will typically drop to between 8 & 10 volts while under starting load. Dropping to 6 volts can often cause electronics to drop off line, & may cause relays to drop out, as well. Try eliminating 'stuff' that's between the battery & starter. Eliminate the master contactor by putting both heavy terminals on the same post (this will obviously power up the plane even with the master switch off). Try starting the engine & see if your symptoms change for the better. If so, likely bad contacts in the master contactor. No change? return to 'normal' configuration & move on. Temporarily eliminate the wing spar interlock by jumping across it's contacts, & try starting. If symptoms change, perhaps the interlock is misadjusted or its contacts are flaky, causing it to be intermittent with vibration. The above are just examples; follow the power circuit and eliminate or 'bridge' each joint in sequence. ________________________________ Message 10 ____________________________________ Time: 10:05:22 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Engine Starter Stalling At 07:01 AM 9/9/2015, you wrote: > >Hi Guys, New kid on the block, and I am looking for some advice. I >have been having starter stall on cold starts. It will stop the >prop a couple of times, and then spin up and start fine. I have >been chasing this for a couple of months now. By the way, this is a >Rotax powered RV-12. I know that when this happens the starter >solenoid chatters. I can hear it. This chatter is caused by >another starter circuit interrupt on the RV-12 called the spar pin >relay. This safety device ensures that the removable wings spar >pins are fully engaged, then completed the circuit to the start >relay. I am now analyzing the battery. I downloaded data from the >Dynon skyview, searched the spreadsheet and came up with a chart >that shows the battery voltage during a typical start. If someone >could take a look at the link below and offer some thoughts about >the battery performance, or offer other advice, I would greatly >appreciate it. Neat chart, and you can see the compression cycles >on the chart. Thanks.........Tom As Charlie points out, without knowing exactly where the Dynon gets its data, the value of that data is weak. The plots show that the voltage doesn't drop below 8v or so . . . normally too high for contactor 'chatter'. I suspect that the data is being gathered at the bus . . . which may well be a voltage different than what drives the starter and/or it's control contactor. Is this a new condition? What size and how old the battery. Have you load checked it? Is there a wiring diagram for the system you can share? Just for grins, you might try clipping a charge car battery across the ship's battery and repeat the cold start experiment to see if there's a marked difference in behaviors. Bob . . . ________________________________ Message 11 ____________________________________ Time: 10:07:49 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Pitot Heat Ground At 04:55 PM 9/8/2015, you wrote: > >I read the faqs, and know the recommendation to just take the pitot >ground to the chassis. > >But I have a specific situation in mind, and would like some >thoughts on it. I'm building an RV14 and the pitot heat controller >will be about 4 feet outboard of an ADAHRS in the wing with a built >in magnetometer. I figured if I ran the 14V/Gnd pair together as >far from the magnetometer as possible I stood a chance of not >interfering with it when the heater is on. > >I've gotten a Dynon heated pitot tube with controller. In this >controller the aluminum controller box is connected to ground as is >the ground lead leaving the box. Dynon says to a) not use the box >for ground, and b) run a ground wire all the way to the battery. NOBODY should ever need to run any applicance wire(s) ground or otherwise, directly to the battery. Can you point us to a copy of the system wiring diagram? Do you KNOW how much power the pitot heater needs? Bob . . . ________________________________ Message 12 ____________________________________ Time: 11:16:09 AM PST US Subject: Re: AeroElectric-List: Pitot Heat Ground From: Lyle Peterson I was going to say what Bob says here. The battery posts are for one, and only one, purpose. That is the connect for the main supply cables for the vehicle. No other wire should be attached at that point. Terminal strips are for that purpose. Wiring connected directly to the battery posts will corrode. Even large battery cables will corrode internally. I have a ten inch cable that ran from the battery to the starter solenoid that was green under the insulation for its entire length. This reduces the useable conductor in the cable and restricts its ability to carry the required current. With smaller gauge wires that reduction is tantamount to cutting the wire. On 9/9/2015 12:06 PM, Robert L. Nuckolls, III wrote: > At 04:55 PM 9/8/2015, you wrote: >> >> >> I read the faqs, and know the recommendation to just take the pitot >> ground to the chassis. >> >> But I have a specific situation in mind, and would like some thoughts >> on it. I'm building an RV14 and the pitot heat controller will be >> about 4 feet outboard of an ADAHRS in the wing with a built in >> magnetometer. I figured if I ran the 14V/Gnd pair together as far >> from the magnetometer as possible I stood a chance of not interfering >> with it when the heater is on. >> >> I've gotten a Dynon heated pitot tube with controller. In this >> controller the aluminum controller box is connected to ground as is >> the ground lead leaving the box. Dynon says to a) not use the box >> for ground, and b) run a ground wire all the way to the battery. > > NOBODY should ever need to run any applicance > wire(s) ground or otherwise, directly to the > battery. Can you point us to a copy of the > system wiring diagram? Do you KNOW how much > power the pitot heater needs? > > > Bob . . . > > http://www.matronics.com/contribution ________________________________ Message 13 ____________________________________ Time: 11:52:20 AM PST US From: Ryan Brown Subject: Re: AeroElectric-List: Pitot Heat Ground I don't see anything in the dynon installation manual about connecting directly to the battery. http://dynonavionics.com/downloads/Install_Guides/Heated_Unheated_AOA_Pitot_Probe_Installation_Guide_-_Rev_C.pdf` It says: Do not connect the Black (Ground) wire to the airframe as a Ground connection. Doing so will introduce high currents (10A) into the airframe. This can introduce a significant voltage drop, and potentially cause engine instrumentation, avionics, and audio system electrical problems. Also it says the ground wire should be: Constant connection to ground (not routed through a switch or fuse / circuit breaker). Must be sized to conduct 10A with minimal voltage drop. Ground connection must be constant FOR PITOT HEAT STATUS LINE (White wire) to operate when the controller is powered Off or not functioning. On Wed, Sep 9, 2015 at 11:21 AM Lyle Peterson wrote: > I was going to say what Bob says here. The battery posts are for one, and > only one, purpose. That is the connect for the main supply cables for the > vehicle. No other wire should be attached at that point. Terminal strips > are for that purpose. > > Wiring connected directly to the battery posts will corrode. Even large > battery cables will corrode internally. I have a ten inch cable that ran > from the battery to the starter solenoid that was green under the > insulation for its entire length. This reduces the useable conductor in > the cable and restricts its ability to carry the required current. With > smaller gauge wires that reduction is tantamount to cutting the wire. > > > On 9/9/2015 12:06 PM, Robert L. Nuckolls, III wrote: > > At 04:55 PM 9/8/2015, you wrote: > > > > I read the faqs, and know the recommendation to just take the pitot ground > to the chassis. > > But I have a specific situation in mind, and would like some thoughts on > it. I'm building an RV14 and the pitot heat controller will be about 4 > feet outboard of an ADAHRS in the wing with a built in magnetometer. I > figured if I ran the 14V/Gnd pair together as far from the magnetometer as > possible I stood a chance of not interfering with it when the heater is on. > > I've gotten a Dynon heated pitot tube with controller. In this controller > the aluminum controller box is connected to ground as is the ground lead > leaving the box. Dynon says to a) not use the box for ground, and b) run a > ground wire all the way to the battery. > > > NOBODY should ever need to run any applicance > wire(s) ground or otherwise, directly to the > battery. Can you point us to a copy of the > system wiring diagram? Do you KNOW how much > power the pitot heater needs? > > > Bob . . . > > > * > > > * > > ________________________________ Message 14 ____________________________________ Time: 11:54:31 AM PST US From: Tim Andres Subject: Re: AeroElectric-List: Re: Engine Starter Stalling Don't forget the ground side of the circuit, you can have high resistance anywhere. One diagnostic method is to put a volt meter in series with the ground circuit, ie one probe on the battery negative post and the other on the engine case. You should see about a volt or less while cranking. Do the same on the positive side next, battery positive post and the other on the terminal on the starter. Anything over a volt or so and you have high resistance in the circuit, which can then be easily found by moving the probe backwards from the starter measuring at each terminal toward the battery. Having said all that, your chattering solenoid is pretty typical of a weak battery. Tim Andres > On Sep 9, 2015, at 9:50 AM, Charlie England wrote: > > >> On 9/9/2015 11:04 AM, todehnal wrote: >> >> I did build my RV-12 under EAB rules. Pretty sure Dynon is monitoring the voltage at the Avionics Bus, right at the amperage shunt. As far as the starter, I have hooked a +12 volt lead directly to it, and it functions flawlessly. I also have removed, cleaned, and reattached every connection from the battery plus, through the master relay, through the start relay, and starter, and back to the battery ground post, with no change. I guess my real question should be, is it a problem when the active starter voltage dips below 7 volts? Not sure what I should typically be seeing here........Tom >> >> -------- >> RV-12 with Skyview Panel built EAB by my wife & I. >> First Flight: 11/21/13. It's a keeper....Tom > Does that mean that you *started the engine* by hooking a battery lead directly to the starter? Because if you removed the starter & just spun it up with the battery, that doesn't give you much useful info that you didn't already know (that the windings have some continuity and the bearings allow it to turn). > > If you're monitoring voltage anywhere except at the battery terminals, you really need to know actual battery voltage *at the battery posts* before proceeding further. If it's staying higher than 8-10 volts while cranking, and you're seeing 6 volts at the remote monitoring point, you've got high resistance somewhere in the power circuit between battery & monitoring point. Don't forget that every connection using a terminal on a wire is really *two* connections: the transition in the bolted joint, and the joint between the terminal and the wire itself, whether crimped or soldered. > > Voltage will typically drop to between 8 & 10 volts while under starting load. Dropping to 6 volts can often cause electronics to drop off line, & may cause relays to drop out, as well. Try eliminating 'stuff' that's between the battery & starter. > > Eliminate the master contactor by putting both heavy terminals on the same post (this will obviously power up the plane even with the master switch off). Try starting the engine & see if your symptoms change for the better. If so, likely bad contacts in the master contactor. > > No change? return to 'normal' configuration & move on. > > Temporarily eliminate the wing spar interlock by jumping across it's contacts, & try starting. If symptoms change, perhaps the interlock is misadjusted or its contacts are flaky, causing it to be intermittent with vibration. > > The above are just examples; follow the power circuit and eliminate or 'bridge' each joint in sequence. > > > > > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.