[TG] [TG11] ACU 300 energising relays

[MEPCOLTD]

Hi Raymarine people,

The boat we just installed an EV1 /ACU 300 system on has an original tiller control/constant running hydraulic pump that switched the negative leg and had a common positive connected to the port and starboard solenoids. Rather than reverse the wiring (that affects a lot more than the steering solenoids), we planned to use a simple system that uses the 24v +ve output from the ACU to energise relays and the contact in the relays to complete the circuit on the -ve leg of the original steering circuit

There is no sign of the 24v signal being produced by the ACU, either with the indication LEDs on the relays, nor with a multimeter when the relays are disconnected.

The rudder reference hasn’t been installed yet so we are trying to commission the autopilot without this information.

1. Will the ACU send a 24v signal to another device (solid state relay or multimeter)? Or does it require a certain resistance that a solenoid would provide?
2. Does the drive test in the dockside wizard have to be completed before we see the signal?
3. If the power supply is 24v into the ACU, would we expect a 24v signal to come from either ‘A’ or ‘B’ outputs when we operate the Raymarine power-steer/nfu tiller port and starboard?

Thanks for any further clues!

Cam

[Tom - Raymarine - Moderator]

Hello Cam,

Quote:The rudder reference hasn’t been installed yet so we are trying to commission the autopilot without this information.

1. Will the ACU send a 24v signal to another device (solid state relay or multimeter)? Or does it require a certain resistance that a solenoid would provide?

An ACU300 system won't do anything without rudder reference. This is for safety: with other pilots we can use drive current to detect a stall condition, but of course can't do that through relays/solenoids so have to know if the drive is stalled. ACU300 will not enter Auto unless there's a rudder reference connected, and won't stay in Auto unless it sees the expected movement in response to its drive output.

Quote:2. Does the drive test in the dockside wizard have to be completed before we see the signal?

No. We'd always recommend doing so, but as long as you have a complete system you can just apply power and press Auto.

Quote:3. If the power supply is 24v into the ACU, would we expect a 24v signal to come from either ‘A’ or ‘B’ outputs when we operate the Raymarine power-steer/nfu tiller port and starboard?

Yes, the solenoid output is the same as (or very close to) the supply input.

Regards,
Tom