(DG) ST4000+ and 10 Hz sensor

[vshtonov]

I am trying to figure out if the ST4000+ (5000+) can use/benefit from a 10 Hz heading sensor.

I have an ST4000+ with a rudder sensor, connected to an E80 Classic via Seatalk. The E80 gets its heading from a KVH1000 10 Hz compass. It understands it and uses it for radar/MARPA. The ST4000+ refuses to switch into auto mode (it says OFF COURSE). If I connect the fluxgate to the ST4000+, then it works. The E80 initially gets the heading from the fluxgate via Seatalk but as soon as I switch on the 10 Hz compass, it locks to the faster heading.

I do not mind using the system as it is but Raymarine advises not to have two heading sources active at the same time. I have tried various combinations to get the fast heading into the autopilot (fed the signal to the NMEA0183 port, fed the signal to the ST6001 control head, etc.) and it does not get it.

So, where is the constraint? Am I doing something wrong, is the 10 Hz heading too fast for the ST4000 so it ignores it? What is the recommended way to connect a fast heading sensor to the E80 while disconnecting the fluxgate?

Thank you,
SV Pizzazz

[Derek - Raymarine - Moderator]

Hi vshtonov
Thank you for your enquiry.

The ST4000+ will not benefit from the 10Hz heading sensor and there is no point connecting it to the unit. it will only use the Fluxgate coils connected directly to the rear of the ST4000+control unit.

The ST4000+ will not operate if the fluxgate is disconnected from it.

Regards

[vshtonov]

Thank you, Derek, this makes it clear regarding the 10 Hz sensor. Now, there is the Gyro 2 plus that I also have. If I use this instead of the 10 Hz sensor, it says it has a 10 Hz output for the radar and a 2 Hz output via Seatalk. Would the ST4000+ take that slower heading input via Seatalk or would it still require the fluxgate coils?

On one hand, it looks as if it should work, on the other hand it is too much trouble (the gyro 2 plus needs to be initialized via the E80, etc.). What would be examples of early (Seatalk) autopilots that can benefit from the 10 Hz sensor but are still Seatalk?

[Derek - Raymarine - Moderator]

Hi vshtonov,
The ST4000+control unit still needs the fluxgate compass coils connected direct to the control head.

You could connect the Gyroplus 2 direct to the NMEA input on the E80, but not to SeaTalk, make sure that you turn OFF the Heading bridging within the E80 System integration menu.

thanks
Derek

[vshtonov]

A further question. I managed to get the ST4000+ to work when the 10 Hz heading sensor is connected to an RL70+, which then feeds the autopilot via Seatalk at a reduced data rate. There is no flux gate compass attached to the system.

The E80 does not work (i.e. it sends the heading via Seatalk, the autopilot displays it but does not use it (i.e. it will not engage without the fluxgate)

The Gyroplus I cannot get to work but it is supposed to be workable with the ST4000+ per the instruction manual.

So why does the RL70+ work?

Thanks

[Derek - Raymarine - Moderator]

Hi vshtonov

The St4000+must have a fluxgate connected to it even if there is an external 10Hz compass feed into the system, the reason for this is that the ST4000+ uses the fluxgate for it's short term heading control, but then uses the external 10Hz for the longer term heading control.

The Gyroplus must have the fluxgate connected to it for it to work, but even so, the ST4000+ must have a fluxgate connected to it anyway.

The RL70+is only looking at the heading input and doesnot care what the source is, whereas the ST4000+ always wants to have a fluxgate connected to it.
regards