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Old Nov 10, 2012, 05:36 PM
Thermite + ice = Big boom.
boaterguy's Avatar
Canada, ON, Ottawa
Joined Apr 2009
2,275 Posts
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Getting a radio signal immediately (dx7s)

I've got a dx7 and I've noticed something different about it. When the receiver is first powered it does not instantly send a signal to the ESC, servos, etc. Unlike any other radio i've ever dealt with. For most of my setups this is okay but I have one ESC (twin boat ESC) that just really doesn't like it. RX is an AR8000 w/ satellite.
Is there any way of getting this to work somehow? I don't even have any ideas other than a BEC (Really can't afford the extra weight)
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Old Nov 10, 2012, 06:20 PM
AndyKunz's Avatar
Illinois
Joined Sep 2001
23,478 Posts
Turn on the transmitter first. As soon as the rx sees the tx (which will happen instantly with DSMX) the rx will begin driving servos. If you were in DSM2 mode there could be a short delay while the rx goes looking for the transmitter.

Andy
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Old Nov 10, 2012, 08:31 PM
Air, Ground & Water
freechip's Avatar
Canada, ON, Rockland
Joined Aug 2008
23,834 Posts
Turning ON the Radio first is one of RC's most recommended things to do.

What exactly does the esc not like and do?
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Old Nov 10, 2012, 10:09 PM
Thermite + ice = Big boom.
boaterguy's Avatar
Canada, ON, Ottawa
Joined Apr 2009
2,275 Posts
It is dsmx, and I am turning on the transmitter first (I know it's very recommended)
The ESC is going into lost signal mode, when it is booted up with no signal it won't run, it has to be rebooted (ie. when booting up PWM must be present).
It's only about a half second of connection time, but it's still too much for the ESC.
How do I switch between DSMX and DSMX2?
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Old Nov 10, 2012, 10:32 PM
Air, Ground & Water
freechip's Avatar
Canada, ON, Rockland
Joined Aug 2008
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In the frame rate is where you can change it on a DX8
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Old Nov 11, 2012, 01:36 PM
AndyKunz's Avatar
Illinois
Joined Sep 2001
23,478 Posts
Which ESC are you using, anyway?

There was one old ESC, I forget which, that you had to power up the transmitter, turn on the rx, and this would acquire the signal after a couple seconds (DSM2). The ESC would go into stupid mode, so you would power cycle the model again and then it would work because Quick Connect would instantly connect to the tx. DSMX connects quickly and didn't need to go through that. That's why I'm wondering which ESC you got there.

Andy
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Old Nov 11, 2012, 04:18 PM
Thermite + ice = Big boom.
boaterguy's Avatar
Canada, ON, Ottawa
Joined Apr 2009
2,275 Posts
It's a twin 120A boat esc made by fliermodel (two 120A ESC's in one package with a PWM splitter)
What's this quick connect thing?
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Old Nov 11, 2012, 08:55 PM
AndyKunz's Avatar
Illinois
Joined Sep 2001
23,478 Posts
Neat. That's how I did the twin Victory controls back when I was manufacturing them.

Quick Connect is what a Spektrum receiver does in DSM2 mode when it comes on. The first thing it does is check for signals on the last two frequencies it was using, in case it lost power before the transmitter. A DSM2 transmitter will always come onto new frequencies when powered up, so this would enable the rx to know if it has experienced a temporary power loss (called a brown-out).

DSMX mode doesn't need to do that because of how it operates, on 23 frequencies instead of 2.

Since you are using a DX7 I assume you're in DSM2 mode. What you need to do is make the initial connection to the model so you can control servos. Your ESC will be in "stupid mode" - it is hearing the rx, but won't do anything. Now you power down the ESC and rx, and then power it up again - LEAVE THE TX ON! Quick Connect will cause it to immediately hear the tx and the ESC will be satisfied and arm properly.

Andy
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Old Nov 12, 2012, 06:06 AM
Thermite + ice = Big boom.
boaterguy's Avatar
Canada, ON, Ottawa
Joined Apr 2009
2,275 Posts
I'll rebind in dsm2 mode and try that, right now it's in dsmx (that was default when I got it.
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Old Nov 12, 2012, 07:04 AM
Air, Ground & Water
freechip's Avatar
Canada, ON, Rockland
Joined Aug 2008
23,834 Posts
Boater guy, are you part of OVR?
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Old Nov 12, 2012, 02:03 PM
Thermite + ice = Big boom.
boaterguy's Avatar
Canada, ON, Ottawa
Joined Apr 2009
2,275 Posts
Ottawa valley racers? No, I might join next year but I'm not sure, with a part time job it's hard to coordinate.
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Old Nov 13, 2012, 07:30 PM
Thermite + ice = Big boom.
boaterguy's Avatar
Canada, ON, Ottawa
Joined Apr 2009
2,275 Posts
I tried both DSMX and DSM2 and neither of them worked with the quick connect, oh well back to the tactic system.
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