Depth Sounder Offset

[migs]

I sent this to both Simrad and Airmar Support but neither replied to my question.

I recently replaced a faulty Airmar DST800, but now find that I am unable to enter a depth offset into the transducer from our Simrad AP28 panel (as I used to be able to do with the old DST800).
If I select a depth offset value on the AP28, the offset resets to zero after about 5s and the offset is not entered.
I can enter an offset on our B&G Triton displays, but the offset is only held locally in the display rather than being sent to the transducer so the depth shown on our OpenCPN plotter is incorrect.
Please advise how I can enter a depth offset into our new DST800.

The supplier of the DST800 did try to help with the problem but couldn’t come up with a solution. Does the forum have any suggestions?

PS. I appreciate that the DST800 is an obsolete product and that perhaps buying a DST810 transducer might have been better (offsets entered via Bluetooth?). However, replacing the faulty DST800 with the same product should have been a straightforward like-for-like swap, so I wasn’t expecting any problems…

 

[Daydream believer]

Are you trying to set a depth offset that is too small? My old one on a smaller yacht, from quite some years ago, would not accept less than 1 metre. I have no idea if that applies to yours, but it might depending on boat size.

 

[migs]

Good point, but the old DST800 accepted an offset of +0.7m. I was expecting the new one to behave in the same way...

 

[Sandy]

I recently replaced a faulty Airmar DST800, but now find that I am unable to enter a depth offset into the transducer from our Simrad AP28 panel (as I used to be able to do with the old DST800).
If I select a depth offset value on the AP28, the offset resets to zero after about 5s and the offset is not entered.
I can enter an offset on our B&G Triton displays, but the offset is only held locally in the display rather than being sent to the transducer so the depth shown on our OpenCPN plotter is incorrect.
Please advise how I can enter a depth offset into our new DST800.

I wonder why you think that any adjustment is 'sent to the transducer', all of the processing will be done by the chips on the display unit? Even my 40 year old kit that came with the boat worked that way.

You will need to find some way of making the adjustment on the OpenCPN plotter. The transducer just makes a ping and listens for the time it takes to receive the echo, nothing more, nothing less.

 

[PaulRainbow]

I wonder why you think that any adjustment is 'sent to the transducer', all of the processing will be done by the chips on the display unit? Even my 40 year old kit that came with the boat worked that way.

The DST800 stores the depth offset, so it's available on all display devices, otherwise, if you had more than one display, you would need to set the offset on every display.

 

[JohnGC]

Assuming the offset is stored in the "smart" transducer (it looks as though it is in the 810 but I can't find anything definitive on the 800).

Then this has the hallmarks of an incompatibility introduced with a firmware update. Is new firmware available for your AP28?

 

[PaulRainbow]

Assuming the offset is stored in the "smart" transducer (it looks as though it is in the 810 but I can't find anything definitive on the 800).

Then this has the hallmarks of an incompatibility introduced with a firmware update. Is new firmware available for your AP28?

See post #5

 

[PaulRainbow]

I can enter an offset on our B&G Triton displays, but the offset is only held locally in the display rather than being sent to the transducer so the depth shown on our OpenCPN plotter is incorrect.
Please advise how I can enter a depth offset into our new DST800.

I think the Triton has two methods of setting the depth offset, locally and on the transducer. I might be wrong, i suspect you are setting it locally, on the "calibration" menu.

Try "Advanced settings", "Device List", then select the DST 800 from the list. You'll see some info about the DST 800, with an "Options" button, click the button and you should get an option to set the offset.

 

[migs]

Thanks for that; I did set the depth offset using the "calibration" menu. When I can get back to the boat I'll try again using the Triton's "Advanced Settings".

Incidentally, the boat has first generation Triton instruments, and it's possible that Triton2s may behave differently?

 

[migs]

Good suggestion from JohnGC about updating the AP28 firmware as it might have solved the problem, but unfortunately there isn't anything available.

 

[PaulRainbow]

Thanks for that; I did set the depth offset using the "calibration" menu. When I can get back to the boat I'll try again using the Triton's "Advanced Settings".

Incidentally, the boat has first generation Triton instruments, and it's possible that Triton2s may behave differently?

That's should be your problem, the "Calibration" menu calibrates the display, not the transducer.

 

[Sandy]

The DST800 stores the depth offset, so it's available on all display devices, otherwise, if you had more than one display, you would need to set the offset on every display.

Thanks Paul, I was unaware of the DST800 ability to store the offset.

I originally had Stowe kit onboard and the adjustment was a manual lever. Just love the new Garmin digital kit where you type it in.