SeaTalkNG power with ACU-400 - Best Practices

[Keith Pleas]

Chuck (Moderator) pointed to a power FAQ he wrote here: http://forum.raymarine.com/showthread.php?tid=410

...where he listed (among other things) ST70 instruments and the ST-STNG converter. But when using the converter then any ST60 instruments (and other classic SeaTalk(1) devices) are also getting power from the bus. Can they also be "switched" with the power to that bus? Will they behave the same viz power buttons as ST70 instruments? Or do they need to be powered up and down separately?

My particular installation (see signature) has an ACU-400 which powers the STNG bus so the ACU and bus (with P70R, et cetera) are on one breaker. What are the best practices for turning off the AP power? I have an ACU-400 so my STNG bus is powered by the AP. And I have the breaker switch in my pilothouse so I can turn the AP off if it mis-operates while underway (I don't think Raymarine documents an interrupt / kill / emergency switch as some other manufacturers do). And I can turn the internal GPS on my a78 back on if necessary (plus I have a redundant nav system power isolated on a N2K network). And I have configured that other nav system (Coastal Explorer on a laptop) to use the EVO to keep it in sync with the AP per our other thread. If I turn off the STNG bus (by opening the AP breaker), it has a secondary nav source it can switch to so I'm not particularly worried there. But, ideally, I'd like to just leave the AP - and STNG bus - powered up all the time (95% at the dock on reliable power). So...is leaving the AP system (and STNG network) on 24x7 a good practice? Or are there some discrete components in the Raymarine gear in my signature - like capacitors - with a finite life, even if that life is in years?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Keith,

General comment regarding power: When considering power circuits for a vessel, consideration should be given to how the equipment within the system will be used and maintain the greatest level of system functionality in the event of a catastrophic failure of any single piece of equipment. Hence, it is considered a best practice to NOT power the SeaTalkng backbone featuring critical devices (ex. Raystar 130 GPS Sensor, etc.) from an autopilot ACU/course computer, as a catastrophic failure of the autopilot may prevent the autopilot ACU/course computer from supplying power to these system critical devices.

Q1. ...where he listed (among other things) ST70 instruments and the ST-STNG converter. But when using the converter then any ST60 instruments (and other classic SeaTalk(1) devices) are also getting power from the bus. Can they also be "switched" with the power to that bus? Will they behave the same viz power buttons as ST70 instruments? Or do they need to be powered up and down separately?
A1. ST60 instruments will be powered ON whenever power is present within the SeaTalk bus. As the ST60 instruments will be powered via the SeaTalkng backbone via a SeaTalk to SeaTalkng Converter(s), switching power ON to the power circuit supplying the SeaTalkng backbone will cause the ST60 instruments return to the ON power state.

Q2. My particular installation (see signature) has an ACU-400 which powers the STNG bus so the ACU and bus (with P70R, et cetera) are on one breaker. What are the best practices for turning off the AP power?
A2. Switching OFF the autopilot control head will not switch off power to the ACU or any SeaTalkng component other than the autopilot control head itself. The best practice for shutting down the autopilot is to switch OFF the power circuit supplying the ACU.

Q3. ideally, I'd like to just leave the AP - and STNG bus - powered up all the time (95% at the dock on reliable power). So...is leaving the AP system (and STNG network) on 24x7 a good practice? Or are there some discrete components in the Raymarine gear in my signature - like capacitors - with a finite life, even if that life is in years?
A3. Raymarine neither publishes mean time between failure nor expected life data for its products. The bottom line is that product life will typically be maximized by not power/switching the product OFF when it is not in use.

[Keith Pleas]

I would be OK leaving everything on but that includes the P70R and I'm not thrilled about leaving displays on continuously. The a78, of course, has its own power control. And the ST60 RAI has some background lighting that must have a finite life given its now ancient technology.

I guess I'll just leave the Evo and the STNG bus powered up except for extended downtime through the winter, and individually switch the displays (a78, P70R, ST60 RAI) manually.

[Chuck - Raymarine - Moderator]

Keith,

There are no hard/fast rules for powering equipment and as indicated previously, how one intends to use the equipment should be taken into account. Unlike the i50/i60/i70/ST70 products, the ST60 instruments do not feature power buttons. Should it be desired to maintain power to the SeaTalkng backbone, but have the ST60 instruments OFF at times, then it would be recommended that the power lead (red) of the SeaTalk bus (not to be confused with the SeaTalkng backbone) be interfaced to a switch which may be use to open or close the SeaTalk bus power circuit.

[Keith Pleas]

Thank you Chuck.

Since it appears that pushing rudder data to ST via the STNG gateway is not supported and that the Evolution AP cannot make use of RFU data via ST (other than to display on STNG instruments like the P70R), then I'm going to take the ST60 RAI off of the ST network and go back to operating it standalone. And I'll have to think about whether I want to run a second RFU or whether I should go back to "Y"-ing the signal from the one I have and just putting up with the needle dithering. Or maybe dump the ST60 RAI altogether and just use the ribbon atop my P70R.

[Chuck - Raymarine - Moderator]

You're welcome.