Redundant receiver Jeti module

[graham stanley]

The new Jeti "intelligent switch" seems a solution to my concerns of two Rx driving two sets of servos. I appears that with this device the signal from two Rx is compared and the best one fed to a servo. So if one Rx fails the "intelligent swiches" (more than one as each only protects one channel, though with outputs for two parallel servos) select the remaining valid signal and feed is to the servo(s). In addition a failsafe function is built in, presumably in case the Tx or both Rx fail. The main advantage is if one Rx fails ALL the servos should continue to function.

This sounds similar in principle to other Rx sensing devices, but with the advantage (or otherwise) of having one per channel, giving greater redundancy, albeit with more components and thus greater probability of failing.

Please can those with greater knowledge and experience than I comment on the virtues (or otherwise) of this module. The cost is £31.90 for two units, to cover two channels and up to four servos.

Text below is the suppliers wording -
The Jeti EnLink 2RS is an intelligent switch for redundant control of 1-2 servos. Using parallel Duplex receivers (Or one Duplex receiver and a 35mhz receiver), the Enlink 2RS connects to both receivers and provides a redundant signal and power-supply for the attached servo. Two servos can be connected, where both servos serve exactly the same function.

The Enlink 2RS units are sold in pairs. The quoted price is thus for two units.

This intelligent switch will automatically choose the best signal from the two receivers and will power your servos from the highest input voltage. The Master and Slave receivers do not need to be operating at the same voltages, but the EnLink 2RS will always supply any servos with the highest voltage available.

All wires are heavy-duty, supporting a maximum burst current of 12A and a continuous current of 3A.

Please note that the EnLink 2RS does not regulate the input voltage and will not serve as a standalone voltage regulator.

The master receiver must be a digital receiver in order to provide a true 'off' signal to the Enlink unit in case of signal failure.

[Rob Buckley]

Looks like a clever little thing!

The trouble is, it reintroduces a single point of failure into critical flying controls.

If one of these is fitted to the elevator channel, if it fails you could well be left with no elevators at all. All the multiple batteries, redundant switches & dual receivers are bypasses by the failure of this little device.

Admittedly, being solid state with no moving parts, it should be fairly reliable, but the manufacturers always seem reluctant to publish reliability figures & failure modes.

Unless both receivers were turned on & tested in sequence, these modules would mask a failed receiver or battery by automatically using the signal from the good receiver. If not detected before flight, this could lead to the model being flown with just one working battery / receiver.