Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 09-10-2013, 15:15   #16
R_C
Registered User

Join Date: Oct 2009
Location: Florida
Boat: 38' Marine Trader
Posts: 115
Re: Simrad Robertson RF300 Testing

Quote:
Originally Posted by tayana55 View Post
Can you send a photo or attach to this thread ?
Here are two photos. The red circles highlight the two green caps in question.
Attached Thumbnails
Click image for larger version

Name:	J300 board.jpg
Views:	128
Size:	140.7 KB
ID:	68406   Click image for larger version

Name:	J300 caps.jpg
Views:	119
Size:	121.1 KB
ID:	68407  

__________________

__________________
R_C is offline   Reply With Quote
Old 09-10-2013, 15:47   #17
Registered User

Join Date: Apr 2012
Posts: 61
Re: Simrad Robertson RF300 Testing

Quote:
Originally Posted by R_C View Post
Here are two photos. The red circles highlight the two green caps in question.
Thanks for the photos.
I'm pretty certain that they are inductors
__________________

__________________
tayana55 is offline   Reply With Quote
Old 09-10-2013, 22:01   #18
R_C
Registered User

Join Date: Oct 2009
Location: Florida
Boat: 38' Marine Trader
Posts: 115
Re: Simrad Robertson RF300 Testing

Thanks for the inductor tip. I'll do some investigating.
__________________
R_C is offline   Reply With Quote
Old 14-10-2013, 12:12   #19
Registered User

Join Date: Oct 2013
Location: Netherlands
Boat: Gibsea 33
Posts: 3
Re: Simrad Robertson RF300 Testing

Dear R C,

I have a Simrad AC12N autopilot together with parts that I "canabalized" from my broken Simrad AP14 autopilot. Unfortunately I do not have access to my rudder making it nearly impossible to install an RF300 rudder feedback unit. It is however very easy for me to design a circuit that determines the rudderposition based on counting the number of rotations of an axis inside the drive unit. I would however now need to emulate a RF300 unit.

When I was reading through this thread I noticed that you wrote that the RF300 produces a 3400 Hz signal at its center position with a 20 Hz change for every degree, so for -50 deg to + 50 deg the RF300 produces a 2400 to 4400 Hz signal. Is this correct? Do you know if I can use a square wave form or do I need to use a sinus? Do you also know the amplitude of the feedback signal?

Thanks in advance for any help/advise given,
__________________
mdejong is offline   Reply With Quote
Old 14-10-2013, 13:54   #20
R_C
Registered User

Join Date: Oct 2009
Location: Florida
Boat: 38' Marine Trader
Posts: 115
Re: Simrad Robertson RF300 Testing

mdejong,

That is correct. According to the RF300's specs it produces a 3400 Hz signal at center and +/- 20 Hz for each degree of change.

Unfortunately, I do not have a scope so I cannot test the RF300 directly. However, according to the help I received at Simulate an auto pilot's rudder feedback unit | Electro Tech Online the output of the 555 timer circuit I used to test is a square wave with an amplitude of a little under 12V.
__________________
R_C is offline   Reply With Quote
Old 15-10-2013, 13:05   #21
Registered User

Join Date: Oct 2013
Location: Netherlands
Boat: Gibsea 33
Posts: 3
Re: Simrad Robertson RF300 Testing

Dear R C, thanks for the information. I'll build some kind of emulating circuit (most likely by using a microprocessor). Out of curiosity, how did you power your 555 circuit? Did you power it by means of an external PSU or did you power it over the 2 connections wires?

I am wondering how Simrad manages to send a feedback signal to the auto pilot whilst powering the RF300 over the same wires. They must be superimposing the feedback signal onto a DC supply voltage but without a scope and a working RF300 it will be hard to find it out for myself.
__________________
mdejong is offline   Reply With Quote
Old 15-10-2013, 15:42   #22
R_C
Registered User

Join Date: Oct 2009
Location: Florida
Boat: 38' Marine Trader
Posts: 115
Re: Simrad Robertson RF300 Testing

mdejong,

I powered my circuit with the two connection wires. I tested voltage between the two RF300 connectors and ground on the J300 board. The one that tests close to the supply voltage I connected to Vcc on the 555 circuit. The other tests at about 1.1 VDC, which I connected to the 555's output pin. Oddly, it works without connecting the 555 circuit's ground to the J300 ground.

I want to learn more so I ordered a DSO yesterday. This will be my first use of an oscilloscope but I'll let you know what I learn when I look at the RF300's signal.
__________________
R_C is offline   Reply With Quote
Old 17-10-2013, 12:58   #23
Registered User

Join Date: Oct 2013
Location: Netherlands
Boat: Gibsea 33
Posts: 3
Re: Simrad Robertson RF300 Testing

RC, I agree that is seems odd not to connect the 555's GND. But if your simulator is working with a 2 wire connection, I will skip my idea of using a micoprocessor and simply use the 555 circuit design. I would be verycurious to see the wave form on an osiliscoop. Thanks again for the information, it is really usefull.
__________________

__________________
mdejong is offline   Reply With Quote
Reply

Tags
paracelle, simrad

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 08:21.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.