Maximum Gain Values with 'No Sensor Status'

  • Hello Richard et al,

    I've experienced some unexpected extreme oscillations on an aircraft I've had set up with iGyro SRS for a couple of years and many flights. So I have confidence in the gain and speed factor settings.

    When landing I've noticed that the display is showing 'No Sensor'. A receiver power cycle returns the status to 'searching' and then 'Logged In'

    This has happened on 3 separate occasions, so I investigated (yes I'm an engineer). This is a summary of what I found.

    1. It only occurs if your power up the receiver before the transmitter - I know you shouldn't but it's easily done and in the era of 2.4GHz gear it's no longer an issue - normally.

    2. When you power up the transmitter and the receiver locks - the 'No sensor' status persists and the gain is at its maximum level. On a GPS II device the slow flashing green led changes, after 10-20 seconds to rapid flashing.

    3. If you restart the receiver then normal 'searching' and 'logged in' status results.

    I can't be sure but I think the behaviour is different on version 23 - only this one aeroplane had version 24. now all are at v25 and behave the same way. My other devices were all on version 23 and I think they consistently worked with the GPS sensor and soon as the Tx was switched on. I can't revert to v23, because I upgraded to v25 before I suspected v24/25 might be a problem.



  • Hello,

    V25 only has changes in Spektrum protocoll.

    1. If you have no receiver signal (because transdmitter is oof) then the "No Sensor" is normal. Once the receivers signal is comming one time then it works. If you disconnect the GPS or it has no signal anymore it goes to "LOST" and the gain is reduced to a minimum

    2. If the GPS is not commanded by the iGyro because of missing receiver signal, the GPS goes into "PC-mode" ready for setting it by BlueCom or USB.

    So all your cases are normal- this is nothing special inV25, it will be the same in V23 and V24

  • Richard

    The situation I experience is that the iGyro will not change from 'No sensor' ever if the tx is powered up after the iGyro, so this means it's possible to fly with the 'No sensor' condition and maximum gain.

    I've done some more checks and the results are not consistent. However I get this state in two separate iGyro SRS and GPS II combinations both v25. For what it's worth, I cannot reproduce it on v23 /GPS version 1. ( I forgot I have two still aeroplanes on the older version.

    Since I can reproduce it on two separate set ups i don't think it is a faulty unit causing it.

    It's possible the fault occurs at power up after a long period powered off - the fault was evident the first time I switched on one device after 20 hours off. Subsequent attempts with only a short period off did not show the fault. Power supplies are either Sensor Switches or Gemini II



  • Hello Richard,

    I have taken a short video, but I can't see how to attach to this thread. The allowed file types and size do not permit.

    I've uploaded it to my web site:

    You can hear the receiver power cycle as the Gemini II beeps at power on and off. The Futaba 14SG beeps when transmitting too and of course you can see and hear the servos working when the signal is established.

    There are two Rx power cycles with Rx power on before the TX, the 3rd Rx power on is with the Tx already transmitting. It is only on this last Rx power on that the iGyro display changes to 'searching'.

    As I indicated earlier this situation consistently occurs after a long period powered off.



  • Hello Richard,

    I can now reproduce this situation reliably and consistently. It's all about the timing of the Rx/iGyro/GPS and the Tx power up.

    The 'No Sensor' status will always persist after TX power up and Rx sync, if the TX is powered up after the GPS II led starts flashing rapidly.

    I can reproduce this every time I try it with three different iGyros and three different GPSII devices.

    I cannot reproduce it with a GPS mk1 device - I know this has no LED, but I waited 30 seconds after Rx power up before powering up the TX.

    This all seems to fit the original observation on an aeroplane that I had flown without the problem for many flights before swapping the faulty GPS I for a GPS II.

    I now know that this can be properly avoided procedurally, and that there is no functional failure once locked. However I think an update is preferable.



  • Richard,

    I realise that it's the intended function and there is no fault - as I indicated in my previous post.

    However, it's less than desirable to rely on a procedure to avoid a misconfiguration that impacts flight characteristics.

    Don't get me wrong, I love the Igyro - all my aeroplanes have one version or another - SRS, 3e or Mercury