MGL E-1 EMS setup

[dholly 718]

I've installed the MGL E-1 Engine Monitor System and have a few questions for a Rotax 912UL application. I've posted the same questions on TKF so well see where the experts are.

Info: I re-used the existing EGT thermocouple probe, replaced the existing single CHT thermocouple probe with (2) new NTC CHT K-Type thermocouple probes from MGL, re-used the existing Westach oil temp thermistor-style thermocouple probe and replaced the existing Westach oil pressure sender with a new VDO 150 PSI/10 bar oil pressure sender p/n 360-360-905 (Note: requires 1/8-NPTF thread, VDO p/n shown includes US Thread Adapters not required for Rotax 912UL application).

Q.1) Re: RPM - I have a Rotax tach and a TinyTach (due to suspected error of Rotax tach). I'd like to enable the E-1 tach function for a 3rd opinion. Can I wire the Rotax and E-1 tachs in series by tapping off the engine RPM out supply feed (prior to the Rotax tach) to the Blue DB9 pin 5 of the lower E-1 plug connector? Is there is a specific polarity from the engine feed (didn't think so)? There are three wires into the Rotax tach (I've identified the +12v power supply in from the bus, but would need to break open the wiring bundle to trace the other two). So, if there is a wiring standard for the Rotax RPM feed wires from the engine and Rotax tach, can anyone confirm definitively that the left top pin on the instrument (looking from behind) is connected to +12v, the right top pin is connected to Ground and one of the two wires coming from the engine (which wire, or it doesn't matter which one?) and the lower center pin is connected to the other engine feed wire. Rotax install manual is not clear on this to me. I understand the E-1 tach function will need to be set to 1 pulse per revolution.

Q.2) I've set what I feel appropriate for my 1995 vintage 912UL, but would like to hear your suggestions for EGT, CHT, OT, OP and RPM span values, plus low and high alarm thresholds.

Q.3) Has anyone added a fuel pressure sender and where in-line is best? Any way to add a fuel flow transducer or fuel level sensors (for wing tank fuel remaining or header tank low fuel warning)?

Thanks!

[jerrytex 1]

I have this same exact set up but I hooked the tach into the hotbox. When I get a chance, I'll swing by and see if I can trace the wire from the hotbox to the connector on the tach gauge. The other suggestion is call MGL. I made several calls to them to get mine set up and they are the one's that told me where to hook up the tach wire. My tach is still not working 100%. At high RPM's, it will read real high, like 9000 rpm and fluctuate. At low RPMs it closely matches the Rotax tach gauge. I have not had a chance to fool with the RPM sensitivity yet, and feel confident that that is the problem. 

[dholly 718]

Thanks Jerry, that would be very helpful if its not too much trouble. After finally getting everything wired, programmed and operating properly, I'd hate make a mistake now! Maybe you could confirm your span range and alarm settings for me while you're there too.

I think you are correct, if your issue is isolated to high RPM range only, a simply sensitivity adjustment is probably all you need. E-1 manual says some Rotax engines (2-strokes mainly, I think?) may require a 220 ohm ballast resistor fitted between the rev counter input and the ground terminal if you cannot obtain stable RPM throughout the range regardless of any setting of the rev counter sensitivity adjustment screw.

Once I get the RPM hooked up, I'll let you know if I run into any high range fluctuation issues and if the sensitivity adjustment screw on the back solved it for me.

Appreciate the help.

[dholly 718]

I've found Rotax Service Instruction SI-13-1996 (INSTALLATION INSTRUCTIONS OF REV-COUNTER PART NO 966403 AND 966408 FOR ROTAX® ENGINE TYPE 912 AND 914 (SERIES) SI-13-1996 R2 ) which confirms the top right pin on tach is Ground, and lower center pin is the RPM engine feed.

 

Still looking to answer the other questions, thanks.

 

 

si-13-1996-r2.pdf

[wypaul 448]

I don't recall off hand were I set the values for my 912 but I will take a look next time I get to the hangar. 

[dholly 718]

Thanks Paul, I'm thinking I may have set the spans too wide. Also not sure whether to set OP low alarm at 15psi (min OP at startup per Rotax manual) or 22psi (min OP during normal ops). And another question arises regarding max OT. The Rotax manual specifies a normal oil temperature range of 190-230 deg F. For short periods, the temperature may go as high as 285 deg F with synthetic oil. Since I use SportPlus 4, was thinking 120*F for low alarm (min OT for take off) and something between 230 and 285, say 260 or so?

[jerrytex 1]

I see you figured out where to hook it up. Here are some screenshots of how mine is set. Will give a starting point.

 

 

 

 

 

[wypaul 448]

Doug, Sorry I am so long getting back on this.  I have mine set about the same as Jerry with the exception of the oil temp alarm which I set to 270 F which is 15 F below Rotax max.

[dholly 718]

Guys, I'm still having trouble with the RPM function.

I identified the proper polarity then spliced the Rotax rev counter feed from the engine and connected to the proper input on the MGL E-1. The E-1 has a direct ground to the engine as required. On my initial E-1 RPM function setup, which was exactly the same values as Jerry showed except for high/low alarm thresholds, the tach read high. I had to change the Pulse/Rev value from 1.0 to 4.0 to get the correct RPM reading. Why would that be?.

Additionally, the value was jumping around pretty good so I played with the Filter: Scale input. I had written in my notes that typical base value = filter 10-30, which is what I tried, but that didn't seem to make much difference. So back at home I decide to actually [RTFM], and see that filter value should be set to 140 when using Scale: 7000.

Obviously, I will try that filter value next time at the plane, although I wonder if I will need to increase that by a factor of x4 because of my 4.0 Pulse/Rev value?? Hmm, can I even input a filter value of 560?? Manual shows 380 RPM max with Scale: 19000.

In any event, Jerry's screen shots didn't show his RPM filter setting. What filter settings have Rotax 912 drivers / E-1 users find work best for them?

For the moment, I have (3) tachs in the cockpit and all read different. Interestingly, the oem Rotax analog rev counter reads closer to the E-1 than my TinyTach. Now I need to find a prop tach to find out which is most accurate!

Thanks again.

------------------------

The E-1 unit contains a digital filter. This filter is used to achieve a higher resolution of the digital rev counter than is available in ordinary operation. In digital rev counters, resolution is largely dependant on the amount of time given to measure RPM. The more time that is available, the higher the resolution will be. However, on the downside of this, the more sluggish the display will react to changes in engine settings. Resolution with the E-1 is dependent on the number of pulses per rev and the type of measurement method you have selected (pulse fast/slow). The update rate for the measurement is a fixed, fast 0.5 seconds. The digital filter is activated whenever input revs are fairly constant and this results in a very high resolution of the digital RPM display in a short time span. The filter needs to be setup for the expected base resolution. This can be between 10 and 30 RPM for most setups. The filter has the following settings:

Scale -The setting is made dependent on your scale selection from 500 to 20000 RPM. The filter factor is fixed as follows:

Scale 500 – 10 RPM

Scale 1000 – 20 RPM

Scale 1500 – 30 RPM

Scale 2000 – 40 RPM

Scale 2500 – 50 RPM

Scale 3000 – 60 RPM

Scale 3500 – 70 RPM

Scale 4000 – 80 RPM

Scale 4500 – 90 RPM

Scale 5000 – 100 RPM

Scale 5500 – 110 RPM

Scale 6000 – 120 RPM

Scale 6500 – 130 RPM

Scale 7000 – 140 RPM

Scale 7500 – 150 RPM

Scale 8000 – 160 RPM

Scale 8500 – 170 RPM

Scale 9000 – 180 RPM

Scale 9500 – 190 RPM

Scale 10000 – 200 RPM

Scale 10500 – 210 RPM

Scale 11000 – 220 RPM

Scale 11500 – 230 RPM

Scale 12000 – 240 RPM

Scale 12500 – 250 RPM

Scale 13000 – 260 RPM

Scale 13500 – 270 RPM

Scale 14000 – 280 RPM

Scale 14500 – 290 RPM

Scale 15000 – 300 RPM

Scale 15500 – 310 RPM

Scale 16000 – 320 RPM

Scale 16500 – 330 RPM

Scale 17000 – 340 RPM

Scale 17500 – 350 RPM

Scale 18000 – 360 RPM

Scale 18500 – 370 RPM

Scale 19000 – 380 RPM

[dholly 718]

Also, I have set Topscale function to ON. Any reason you all have it off?

Select this function to “ON†if you want the bar graph display to show the upper half of the temperature range only. This results in a higher resolution of the temperature range that you may be interested in. For engine temperature measurements we recommend that you set this to “ONâ€.

[jerrytex 1]

I'll try and get by to check to see what my RPM Filter setting is. Since I haven't fooled around with the RPM sensitivity to get mine working right, I might be in the same boat as you and will have to adjust the filter as well. Truth be told, I don't even really look at the RPM on this gauge since I have an analog Rotax gauge and I am Just so used to looking at it. 

[dholly 718]

Jerry - I went to reset my filter to 140rpm and found it will only allow 10-100 in 10rpm increments. Apparently, when you set the Scale the filter is automatically set per the table shown above. I didn't have my jeweler's screwdriver set with me to change the sensitivity screw on the back of the instrument, will try that next.