[charlesglace]

I HAVE A IO-360 LYCOMING. I NEED TO FIND A TACH SENDER TO WORK WITH MY DYNON EMS D-10 ENGINE MONITOR SYSTEM-DYNON SAYS THAT THE EMS NEEDS 10 TO 12 VOLTS. I NOW HAVE A WESTACH 303DH2T BUT CAN'T GET TO WRK. ANY SUGESTIONS?

 

[Dynon]

Is there a reason you want to use a tach sender rather than just picking the signal off the P leads?

 

[charlesglace]

i guess i will be forced to use that method

 

[RV6_flyer]

Is there a reason you want to use a tach sender rather than just picking the signal off the P leads?

Yes. The LASAR ignition signal only works when the LASAR system is on. The P-lead signals do not work with the LASAR ignition. On a hot day with a hot engine, the LASAR system will be turned off so that the climb can be made on the mags without the spark advance to keep CHT 40 to 60 degrees cooler.

Is Dynon telling me that the EMS D10 RPM will not work the way it is described in the manual? If that is the case, I need to get a RMA and return the unit I purchased because it does not work as Dynon said it would.

 

[Dynon]

We are well aware that some ignition systems do not work with the P-lead setup, and we do support external RPM senders. Do a google search for Dynon and Lasar and you can see that we have been helping people out with connecting this since 2006. Of course it works like we describe in the manual, which specifically requires a 12V or greater pulse, and the LASAR systems don't do this.

I was asking specifically in this case if there was a reason that the original poster didn't want to use the P-leads because some people are unaware that we support that method, which is the cheapest and easiest method we support. He didn't tell me what kind of ignition he had, so I was asking a question to make sure I had all the info I needed to give him an intelligent response. I was not making a statement that other senders do not work.

As for the original question. I have spent 10 minutes looking for a datasheet for the Westach 303DH2T, and I do not find one. We've had people asking about the 303DH2T before, and we have never been able to get a solid answer about what the output of this sensor is. Without that data, there's no way we can support the sensor or even help someone try and use it.

The RPM sender we like to recommend on the Lycoming engines is the one Van's sells under the part number VTACHGEN. They sell a version for engines with and without vacuum pumps. We've had lots of success with these over the years.

 

[RV6_flyer]

Thanks for the response.

I have purchased Westach stuff a couple of times. It either did not work out of the box or quit working shortly there after. I now will only buy Westach if nothing else is available and I have to have it. Yes I do not like Westach products.

I purchased the UMA T1A9-1. It cost more than the Westach. According to the Dynon manual, it should work. Its specs are:
Power: 5-24VDC 10 ma
Output: Magneto dependent pulses --- 95% Vcc Sq. Wave

I believe that this is the same sender that your competitor AFS uses or use to use.

I understand that the EMS D10 requires a 12 volt pulse. Bus voltage should be 13.8 to 14.4 VDC with the alternator working. 12.6 VDC with the alternator off line and a fully charged battery. This should give the Dynon EMS D10 a 13.11 to 13.68 V square wave pulse and as I understand the manual, it should work well. Now if my alternator goes off line and I am down to 12.6 V out of the battery, it most likely may not work at 11.97 volts.

I have a vacuum pump so if the UMA sensor does not work, I will need another one that is driven off my Lycoming tach cable drive. UMA makes one and it is the same spec sheet but input voltage is 5-16 VDC but output is 4 pulses per revolution and the same 95% Vcc Sq. wave.

If Dynon would like a scanned copy of the UMA spec sheet, I can send you one. Send me a PM or email with an email address to send it and I will get it off to you.