Actisense EMU-1 Engine converter analog to Digital

Possibly look into a low pressure switch (10 PSIG) and install in the engine oil system. Use that to turn on the channels that are alarming via relays only when oil pressure is above say 10 PSIG (engine has started and running).

That's a great idea, I could tee the one that's there and put that in series with the alarm line. Something to think about. Thanks Tom.
 
https://www.jegs.com/i/JEGS/555/11200/10002/-1
555-11200_1.jpg
 
Perfect! thank you!

EDIT: Funny I was so focused on the relay board I didn't think about the alarm itself.
Sometimes the obvious isn't. I used these switches, back in the day, in my nitrous oxide systems; they were installed in the fuel side of the system so that nitrous oxide could not be injected unless there was fuel pressure. Saved many an engine....
 
So I think I have all the pieces figured out and will be ordering a 2nd EMU-1 over the winter and have it wired up for spring.

The tach issues I was seeing may be fixed. My preliminary testing seemed to work so far. I made a conditioning circuit from a 1A voltage rectifier and a 1W 12v zener diode with 150 ohm resistor. With the generator and both engines running the tach's seemed very smooth through 1600 rpm. If it wasn't raining here again, I would take it out for a real test run. But this is a whole lot closer then I ever got with the RS11.

I only wish the calibration software for the G2 was more reliable. I feel like I am in the never ending story with this N2K conversion I started back in 2016 ...
 
So it seems there is an issue with the EMU-1's latest firmware and tach signals. Also some other temp issues I am seeing.

https://desk.zoho.eu/portal/actisense/en/community/topic/emu-1-tachometer-issue

They tell me they will have a new firmware fix out shortly, but the date on that article is two years old. They say the older firmware doesn't have an issue and works flawlessly and to downgrade to that. The problem with that is the older firmware doesn't support the custom gauges so that doesn't work either!

Man does any company have their act together these days!?

I will say this, Actisense has some cool tools to use with there NGT-1. They have an NMEA2000 reader that will let you monitor all PGN's and the selected one live and record them. All PGN's on the network are recorded and may be sorted and you may select only the ones you want to view even though they are all there to see. They also have a virtual scope the call ActiScope and that will let you record and monitor every input of the EMU-1 and display it like a scope would. It allows you to record it and display is back later in a loop if you like. I will try and post a pick of that, really cool troubleshooting tools. But of course the best device would not need to have those tools and just work as advertised. Wouldn't that be something!

So for now I am going to go with this and order a second unit and hopefully be done and back working this spring. The things I like most about this are and the reason for sticking with this:

1. Custom sender curves
2. Tach is supper easy to calibrate and tweak
3. Real NMEA 2000 Engine alarms. Meaning engine over temp will display as such on any MFD that supports engine alarms. So no need for a seperate engine display screen or monitor. They come up on all of my MFD's. Still keeping the system monitor as described in @ttmott's awesome write up.
 
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Pretty cool tools to have when you have problems. Especially if there alway hooked up. I have the USB to N2K adapter wired in to the dash with a remote plug in at the helm. And I leave an old laptop on board for just such an occasion.

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upload_2020-11-18_15-34-59.png
 
Not quite sure how I managed it but I am part of Actisense's beta testing for the firmware release of a two year old bug (previously documented on there site) that I saw instantly with my EMU-1. The tach inputs are partially tied together (through firmware???) and weird things happen besides bad tach readings. The N2K outputs for engine data also fluctuates wildly for an instant and gives bad readings which can also alarm, not good. The new firmware fixes some of that along with editable engine hours, nice perk. My EMU-1 is mirroring the tach inputs when only one is connected. They say their not seeing that, so now I have requested an exchange in hope most of what I am seeing is defective hardware. I guess I will see what happens with that and decide if I am staying with this or not. Hopefully this all works out as this is a really cool device now that they have added all of the right features. The EMU-1 really could be a generic ECU like device and bring the older analog engines into the modern era of NMEA 2000 correctly.
 
So I received my RMA replacement and it does the exact same thing as the original unit did. I guess that's a good thing in a strange way. I tried using a zener diode clamping circuit on the tach signal and that fixes everything. So since I am going to use the EMU-1 one per engine this isn't really isn't going to affect me anyway. I am ordering another for the 2nd engine and possibly a third for my generator if the engine hours are fixed right for that. Right now the engine hours are triggered off of the tach signal and I don't have a tach signal for my generator so that is the obstacle there. I could possibly use the alternator for that and not care about the actual reading and only use it for triggering the hours. Looks like spring will be a busy time for the boat. Can't wait! I truly hate winter.
 
After some discussion with Aetna Engineering and Actisense - I came up with this simple clamp circuit to help stabilize the sender output.

upload_2021-1-6_13-24-39.png



These are before and after pics of the signal.

This is with a 10x probe setting:

Note the lower left reading 7v. Thats divided by 10 so it's really 70v signal.

upload_2021-1-6_13-28-58.png


This is after the circuit with a 1x probe setting:

Note the voltage is now ~17v p-p.

upload_2021-1-6_13-31-30.png



Hopefully this will help the eraticies I was seeing with the RPM. Bench testing with an 8901 sender it looks promising. I probably should have gone this route when I was testing the Noland RS11 unit a few years ago.

EDIT: I have posted this info in case anyone is having trouble in general with any of the engine boxes available. These senders are quite popular on the older non-ECU engines. This should work for any conversion box on the market, perhaps the zener would need to be replaced with a lower voltage one.
 
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Thanks for the tip and good luck being the beta tester Guinea Pig.
I know you previously used the Chetco box, but do you have any knowledge or experience with the Veratron EngineBox? These are the listed specs:
• 2 Models for single engine and dual engine configurations
• Status LED
• Operating temperature range -40 °C / +85 °C
• 1x J1939 (2x J1939 Dual Engine)
• 1x M12 5 pins NMEA 2000®
• 1x Input 0–4 kHz for RPM (2 inputs with Dual Engine Model)
• 4x Inputs 0 – 400 Ω (up to 8 inputs with Dual Engine Model)
• 2x Inputs 4 – 20 mA
• 1x Input 0 – 5 V (2 inputs with Dual Engine Model)
https://us-shop.veratron.com/index....onid=50FCDCFA3427C007F0DC59169C36984A.cfusion
 
Man, for all the hassles of the Chetco unit, the RPM was always the easiest part to get set up. Is it possible that the senders are the issue??

I finally came to the conclusion that the easiest way to implement the Chetco was to replace the senders with a pre calibrated model # on the engine.
 
Thanks for the tip and good luck being the beta tester Guinea Pig.
I know you previously used the Chetco box, but do you have any knowledge or experience with the Veratron EngineBox? ...

Yes, unfortunately I do. Varatrons Engine Box allows for manual voltage plotting for each gauge, 5 points if I remember correctly. The biggest issue with Varetron was they did not report the alternator voltage in the 127489 PGN or any other for that matter. They also did not support any type of engine alarm that reports on N2K. I spoke with them directly and they didn't seem to think the battery voltage mattered at all and actually said I should use there new battery monitor instead, which does not report on the engine PGN at all. They clearly do not understand engine monitoring. Which is why I am staying with Actisense.

The G2 is a great analog to digital converter box and would still be using it had my alternator not taken it out, but they never fixed the programming software as promised when I first went with a few years ago. Actisense just released there custom gauge manager which seems to work great, so far with limited testing.
 
Man, for all the hassles of the Chetco unit, the RPM was always the easiest part to get set up. Is it possible that the senders are the issue??

I finally came to the conclusion that the easiest way to implement the Chetco was to replace the senders with a pre calibrated model # on the engine.

Yep, the G2 was awesome with handling the RPM and the rest to be honest. Just wish the software would have worked. Would be nice to reliably program it.

The issue with the EMU-1 is they have a cross-talk problem between the tach channels with large signals. The Aetna Engineering senders have too large of a signal output ~70v @ cruise RPM. So that's why I made the clamp circuit, no signal should be that large and be expected to be usable without conditioning of some sort.
 
Orlando - a couple of curious questions:
Did you put the scope directly on the sensor signal output? If I remember correctly, and if correctly a air gapped Hall effect sensor to the flywheel it should be a clean 5V alternating square wave revealing a frequency of tooth count times RPM.
Why in the world would a product convert a good square wave to a sine wave?
I noticed a frequency of 133 hertz, how is that derived? Assuming you are counting flywheel teeth shouldn't it be closer to 80KHz at idle and 380KHz at high idle?
I'm obviously missing something basic here..... like you aren't using the flywheel....
 
Orlando - a couple of curious questions:
Did you put the scope directly on the sensor signal output? If I remember correctly, and if correctly a air gapped Hall effect sensor to the flywheel it should be a clean 5V alternating square wave revealing a frequency of tooth count times RPM.
Why in the world would a product convert a good square wave to a sine wave?
I noticed a frequency of 133 hertz, how is that derived? Assuming you are counting flywheel teeth shouldn't it be closer to 80KHz at idle and 380KHz at high idle?
I'm obviously missing something basic here..... like you aren't using the flywheel....

Tom, You guessed it, no flywheel counter. I wish I had the nice gear tooth counter for RPM. It would make life a whole lot easier. But I just couldn't find a way of mounting one and didn't want to drill and tap a 3/4 hole that might not work out right and possibly get filings in my rear seal.

But the sender I am using or I should say Detroit was using is Aetna Engineering 8901/2. I have the 8902's on my engines, but I bought a spare single station 8901 for testing way back when I tried to get the RS11 working. The AE senders are AC generators @ 8 pulse's per revolution.

For testing I setup a 3K RPM DC motor with a digital controller coupled to the sender and ran it like that. I also used a laser RPM meter with reflective tape to verify the exact RPM. The scope was across the output unloaded (sine wave) and then with the clamp circuit (square wave). With the clamping circuit and the double digit ratio scaling on the EMU-1 I was able to get within 10 RPM at all speeds. I have since used a 12v zener instead of the 16v. I went with the 16v originally because it was half of what the EMU-1 max signal was, but got better performance with the 12v zener.
 
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So I decided to stay with Actisense based on the testing I have done and how Actisense is responding to my findings. They are also working on getting the ability to have generator hours working as well. Hours based on oil pressure rather then tach. So I ordered a second unit and installed them this past weekend. I also plan on getting a third this spring and left a place to mount it between the other two. Still need to finish up neatening up the wires a bit. I had to cut all of the wire ties on the right hand side to run more yellow wire for the engine alarms.

EDIT: updated electronics pic to include the third EMU-1
PXL_20230301_000824572.jpg
 
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Well I added the third EMU-1 for the generator last month and set all of the engine alarms up for the system monitor that also pop up on the engine displays (GMI20's) as NMEA2000 engine alarms as if they were actual ECU's posting the alarms. Today I spent the day running new wires and replace the sending units and alarm senders. Still have to finish up the wiring a bit but the bulk is done. I am also changing the antifreeze in both engines while I am at it. Hopefully this early start on this stuff will allow a great season ahead!
 
Looking good! Good luck with the sea trial. What are the Maretron boxes?
 
Looking good! Good luck with the sea trial. What are the Maretron boxes?

From left to right is a DCR100, CLMD12 (Digital Switching - moved RIM to side panel) and an IPG100. The DCR100 is being used for zoned alarms triggered by DSM410's and a DSM150. The zones are Helm, Salon and Stateroom. There are a red lighted/sounder for Alarms and a yellow light for warnings in each of those zones. The RIM100 is for part of the systems monitor and the IPG100 is for remote monitoring.

Edit:
PXL_20230301_000824572.jpg
 
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