Raymarine SPX5 heading data conundrum

[Ric]

I have a Raymarine SPX5 wheel pilot, connected to Seatalk1 and flux-gate compass for its heading data.

I have now installed an Evolution linear drive autohelm with EV-1 heading sensor and ACU-100 course computer connected to a powered SeatalkNG backbone (then to MFDs, radar etc).

I have decided to keep the SPX5 setup as backup autohelm, and also possibly for times when I need to conserve electricity such as night passages. I have connected a waterproof ON-OFF-ON switch at the helm to select which autopilot (if any) is in use.

I have a conundrum about what heading data the SPX5 will use when it is the selected autopilot. Since the Seatalk1 and SeatalkNG networks are connected with the appropriate converter, the EV-1 heading sensor will still be putting its data onto the SeatalkNG and Seatalk1 networks, even when the ACU-100 is switched off. If I leave the fluxgate compass connected to the SPX5 will there be a conflict with the EV-1 data? I'd prefer to keep the fluxgate compass if possible, as my idea is to have as much redundancy as possible between the two autopilots.

 

[Ian_Edwards]

I can't really answer the question directly, but I have just replaced an SPX30 with an EV-1 system and removed the fluxgate.

If I remember correctly the fluxgate is connected directly to the SPX and samples it at a higher rate than the rest of the seatalk 1 system, so my guess is that the SPX will still use the flux gate. Will there be a conflict when using the SPX? There is a page in the i70p autopilot set-up which allows you to select the which sensor you use, so it you have more than one depth, wind or whatever sensors you can select, or leave the automatic box ticked.
I was also told by Raymarine technical people that the the flux gate wasn't compatible with the EV-1 or ACU.
You could always go for a test run and try the various combination and see what works and if there are any conflicts.

 

[prv]

If I remember correctly the fluxgate is connected directly to the SPX and samples it at a higher rate than the rest of the seatalk 1 system, so my guess is that the SPX will still use the flux gate.

I don't have any hard info, but I'd agree with this supposition. The fluxgate on the older autopilots is an analogue connection; although the box is mounted remotely, in a system architecture sense it's "part" of the pilot, not a network-connected external device. I would expect the older pilot to use this and ignore any heading data on the network; if you're lucky it might even fall back to network heading if the fluxgate were disconnected.

At the end of the day, why not just get out there and try it?

Pete

 

[laika]

To those that have just upgraded their Raymarine autopilots....do you notice a difference?

My ST7000 is rather sick (not the simple duff relay I thought it was and the control head's keys have been a nightmare for years). I'm weighing up getting it fixed vs. buying new. I do understand that I'll see rather more of a difference with new vs my non-gyro unit than you folks with your SPXs would have, but are you happy with your new autopilots?

 

[Ian_Edwards]

I had a S2G auto pilot complete with 6002 control on my previous boat. The G was the rate gyro option. I upgraded to an SPX when I change boat and didn't notice any difference, in fact the I think the SPX was a lemon, I had no end of problems with it, which cost me a lot of time, but fortunately not alot of money because it was under guarantee. Last winter I change to the EV-1 and an ACU400. I think this is a much better system, so far (about 500 miles) I haven't had a problem and it seems better at keeping course than the SPX.

 

[Ric]

I don't have any hard info, but I'd agree with this supposition. The fluxgate on the older autopilots is an analogue connection; although the box is mounted remotely, in a system architecture sense it's "part" of the pilot, not a network-connected external device. I would expect the older pilot to use this and ignore any heading data on the network; if you're lucky it might even fall back to network heading if the fluxgate were disconnected.

At the end of the day, why not just get out there and try it?

Pete

I spoke with Raymarine technical support this morning, and they weren't sure either what would happen, though they leaned towards the opinion that the SPX5 would be conflicted when in stand-alone mode, because it would be getting information from the EV-1 as well as the flux-gate compass.

To add to the confusion, I note from the EV-1 manual that it is capable of combining its own data with other heading data when multiple sources are available, so perhaps it will just de conflict itself from the flux-gate compass.

However, despite Raymarine's pessimistic opinion, I tend to lean towards prv's theory that the SPX5 will automatically prioritise the heading data from the directly connected fluxgate compass since it presumably is programmed to already discard any other heading data on the network (which in earlier days would be slow gps derived data).

As IE writes, I don't think the problem will be solved until I test the new system hopefully next week. If there is a problem I will still be able to hack into the EV-1 spur cable and connect the red/black power cables to the ACU-100 so that the EV-1 is only powered up if I have selected the Evolution autopilot.

 

[Ian_Edwards]

If you are using an i70 p or r autopilot control head you can select the heading the autopilot will use. I've just checked the manual, page 59 provides the info'. On my system where I only have the EV-1, I get the options, in the form of boxes to tick, of auto and EV-1, I guess that if the system can "see" the fluxgate it will show up on that page, and you can select the one you want to use. However, I was told by Raymarine tech support that the fluxgate isn't compatible with the ACU.
I don't know what the situation is if you are using an older control head, or whether they are compatible with the ACU.

 

[Ric]

Raymarine also told me that the EV-1 is not just a heading sensor, it is also the course computer. I thus don't think I will be able to select heading input when using the SPX5 as I suspect the SPX5 will either default to the flux-gate compass or will be conflicted by the course correction data being outputted by the EV1. Anyway, I hope to finally finish the refit by the weekend so will know for sure in a few days.

 

[Ric]

I finally tested the system to see what happens.

If I select the ACU-200, everything works fine.
If I select the SPX-5, the P70 detects the EV1 on the network, but finding no AC-200, it gives an error message "no drive actuator connected". There is no option to force it to "see" the SPX5.
I therefore carefully opened up the EV1 spur cable and wired the red & black power cables to the ACU-200, so that the EV1 is only powered when the ACU-200 is selected. This works - when the SPX5 is selected, there is no power to the EV1, so the P70 sees the SPX5, and system works fine (the SPX5 gets its heading data from a flux-gate compass attached to it directly). The only problem now is that when both autopilots are off, there is no heading data supplied to the network. I have therefore wired a five-pin relay to the SPX5 power supply, controlling power to the EV1, so that the EV1 is disconnected when I select the SPX5. Everything now works fine, and I have two independent autopilots with a substantial degree of redundancy between them, since they each have their own heading data and are on two separate data networks.

 

[ianj99]

For the sake of completeness, the SPX autopilots must have the fluxgate compass connected and cannot be made to use heading data via Nmea, ST or STNG by disconnecting it and there is no option to select the source manually.

I found this out myself because Raymarine were not 100% sure, and I wanted to 'improve' my SPX30 by using an Airmar gps/heading solid state sensor. (the yacht being all steel, the fluxgate compass has to be 5feet above the wheelhouse / 10' above the waterline, so is exposed to greater pitch, yaw and roll accelerations)

The older S3 autopilots will prioritise heading data from Seatalk or Nmea even if a fluxgate is connected (which sort of tells you what Raymarine think of their own fluxgate compass!), I expected the same from the SPX30 but wasn't to be.