RCU Forums - Powerbox Expander SRS

[HR][/HR] I thought I would share my experiences with the new Powerbox Expander and its use with my Jeti DS16.

As I had a little credit with Dave at Motors and Rotors so I decided to try out the PB Expander SRS . I called and ask M&R to send me one down along with a PB Gemini II reg, Dave as usual was very quick and both items arrived next day less than 20 hours after my call.

The PB Expander unit is very light at 25g and at 55x40x14mm about the same size as my Jeti 10ch Rx, it has a Multiplex power in socket in the centre of its top edge and the whole unit is rated at 30amp peak. Along its sides there are 18 ports for servo leads, 1-12 down the right edge and 13-18 on the lower left edge, there are also 4 more ports at its upper left edge for USB, 2x RX (Sats) and one marked Misc (S Bus-EX-Bus out?). I must admit I prefer to see the sockets along its edge rather than on the face like the 10ch Jeti and CB200 that I would normally use, its just looks a bit tidier to my eye when installed.
First thing I had to do was setup the Expander to enable it to be used with my Jeti as by default they come set to Futaba. This can only be done using a USB dongle and the Powerbox Terminal program you need to installe on a computer, I happen to have a PB USB dongle but I'm told the Jeti and Multiplex ones will also work . Unfortunately when I tried this the PB Terminal did not recognise the Expander, a quick email to Richard and his team revealed that the "Terminal program" was not yet ready to use with the Expander but give him an hour or so and he will let me have an update. True to there word they emailed me a program file to update the Terminal , I then installed as instructed and magicly a new tab opend up within the Terminal program, it was then just a case hooking it up and choosing one the Jeti options of Jeti EX or UDI.

PB have now updated there online "Terminal" program so you should not have the same hurdle to cross.
http://www.rcuniverse.com/forum/atta...879684&thumb=1

Jeti options are UDI or EX which one?
I chose to try EX first and in duel path mode so my Jeti Sats were set accordingly with servo timing at auto, 16chs and failsafe disabled using my explorer function within my TX, then they were bound in the duel path mode. This setup gives me outputs for all my TXs 16ch and the remaining outputs 17-18 simply hold the servo at neutral. One big drawback came to light with using the Expander with my Jeti in EX mode, that is there is no facility in the Expander itself for any telemetry so you don't get any telemetry ports, add to that the EX port on the Sat is now used to connect it to the Expander so that is now also unavailable.

I then decidided to try it with my second Jeti option and use UDI to see how that stands up, again I reset the Expander on my computer accordingly and reset my Sats to UDI mode. This setup also worked straight away and frees up the EX ports on the Sats allowing two inputs for telemetry. The trade off is unfortunately with Jeti on UDI you only get 12ch.

Setting up a failsafe.
This at first was a problem, you cant use the failsafe within the Jeti Sats themselves as this will confuse the heck out of the SRS built into the Expander just as it would with a Jeti Central Box. Unfortunately at the time I was trying out the Expander there was no failsafe facility within the Expander itself. A further email to Richard at PowerBox asking how to overcome this resulted in a promise to update the Expanders software but to give him the weekend to sort it out. Again "Team PowerBox" came through and V.02 software for the Expander was written now with a failsafe. With this update I have now been able to choose ether hold or present on all of the possible 18 outputs. The preset failsafe positions are set by using your Tx wile set to were you want the outputs to be with wile the Expander is also connected to your PC. With this in mind one thing you will need on site from now on with the Expander if you wish to reset failsafe will be your laptop.

Gemini II
Power supply to the Expander requires using a single multiplex plug, this is a bit of a faf if using the PB Gemini as its "power out" is delivered via two servo fly leads. To connect up to the Expander means having to cut off one end of each lead and solder them to a single Multiplex plug, not a big problem but would like to see the option of two servo type plug inputs on the Expander, perhaps over the top or along side the existing Multiplex socket. Im not sure if you can "back feed" through unused sockets on the Expander instead of using the multiplex socket, but I will ask and get back, also although the new Gemini is rated at 12amps the two light weight leads "it has to use" would in reality only cope with half this?
The other slightly awkward feature I've found wile using the Gemini II is that its inputs and outputs are arguably on its "underside". So if its to be mounted to enable its "Mag Switch" built in to the unit on its face results in the plugs dangling underneath the tray its mounted too, hence inaccessible. There is also no safety clip feature for the plugs so make precautions or there liable to "fall out" under positive "G". I guess if you really want to use the Gemini's Mag Switch you could mount it to the fusalages side and have the plugs facing horizontal and operate the switch from outside the airframe. For now I will mount it on its back and use the more usual PB switch that it comes with on a ribbon cable.

http://www.rcuniverse.com/forum/atta...879823&thumb=1 http://www.rcuniverse.com/forum/atta...879824&thumb=1 http://www.rcuniverse.com/forum/atta...879878&thumb=1

The Jeti MAX BEC would be ideal for The PB Expander, it has the right size leads and plugs, you can use its remote mag switch or even the RC switch if using Jeti. It also will give you full telemetry of the battery states and has higher amp potential. Oh and is its a bit cheaper than the Gemini.

http://www.rcuniverse.com/forum/atta...880010&thumb=1

If you are going to use a HV setup on the Expander and don't require a reg at all there of course is no battey backer built in as with say the CB 200 so a Jeti DSM 10 or PB 12 switch will ideal giving you full battery redundancy. The PB 12 switch has a traditional built in HD mechanical switch, the Jeti DSM 10 has a choice of magnetic failsafe switch on a fly lead or an arming plug.

http://www.rcuniverse.com/forum/atta...388756&thumb=1 http://www.rcuniverse.com/forum/atta...880049&thumb=1

Conclusion
The Expander gives me the use of all the DS16 channels but at the expense of loosing telemetry which is a shame as telemetry is one of the DS16 best features.
"With out" the ability to remap or duplicate the Expanders outputs which is std on "all" my Jeti RXs and Central Boxes its not really "Expanding" well not for Jeti users.
However For JR XG14-28X DMSS users and the DX18 it will be a very handy bit of kit and the only easy option if you need more than 11ch PWM chs.
(That's until JR and or Horizon wake up and make some 14-18 ch RXs.)
Its neat and tidy and PB units are well backed up so perhaps its software will be further updated making it more useful in the future?
For Me the using a Jeti CB 200 is cheaper and although it "only" has 15 active chs it dose have a battery backer, servo overload protection and full telemetry.
There is a "S" bus feature on the Expander but I have little use for any type of S Bus, I just don't see the point but that's a whole other discussion :rolleyes:
If you need to adjust its failsafe after the early flights on site once the airframes trimmed "I always do" don't forget you will have to bring a laptop along with you.

Hope you all find these ramblings usefull. Mark V