Can I use two temp guages on one engine temp sensor?

[centrix29]

Hi all,

I've been trying to add a temp sensor on my dash so I don't have to look back or ask my family to tell me if the genset is running hot.  We have an info panel installed on our cupboards but I can't see it while we travel.  I bought this guage and I'm trying to hook it up to the same sensor my genset info panel uses on the engine.  I get the correct reading on my info panel but nothing on the new guage.  If I connect only the new one, I get the correct reading.

Any thoughts would help!   

Thanks!

Pat

[Len Silva]

That's not going to work like that.  You can buy dual output senders that will operate two gauges.  They are often used on boats.  The gauges and sender must be properly matched.

[robertglines1]

easiest is to put a T into sensor hole and run two sensors..are you wired to sensors parallel or series ? Lin noticed you post while typing.what if he wired them in series would they only read 1/2 of actual?

[centrix29]

Those are two great ideas guys!  Thank you so much for your expertise.

Pat. 

[Sean]

Datcon makes a pair of gauges designed to run from a single sender (one output).  That's what we use on our genny -- one gauge at the genny enclosure and one on the dash.  Same with oil pressure.

-Sean
http://OurOdyssey.BlogSpot.com

[luvrbus]

I have always ran 2 gauges of 1 sender from the generator like Sean never a problem for me

[TomC]

How about just using a video camera.  Many yachts have just one set of mechanical gauges in the engine room with video cameras to watch from the bridge.  Good Luck, TomC

[Len Silva]

I have always ran 2 gauges of 1 sender from the generator like Sean never a problem for me

It depends on the type of gauge.  Tachometers may work as they are just counting pulses.  Resistance dependent gauges like pressure and temperature, even if they work, will not be accurate because the resistance is divided.  There are both senders and gauges designed for dual positions.

In addition, the gauge must be matched to the sender as there are several different resistance types out there.

[Don4107]

How about a switch to select the gauge you need at the time? Wire it to the control location you have now.

[luvrbus]

Centrix you will find out here you try your idea first then if doesn't work then you ask  lol

[JohnEd]

How about a switch to select the gauge you need at the time? Wire it to the control location you have now.

This is how I did it.  I drilled out the drain plug for my differential and pipe threaded it for the sender thread.  I used a sender identical to my engine coolant and connected it to a switch on the dash.  When it is in the differential temp sensing posit I get a red led light over the gauge.  This would work with a lot of sensors we use and would be reason enuf to change out sensors and meters to accommodate.....I did.

MORE importantly:  While you are in there and mucking about and running wires and such consider this:  Nobody is ever watching when the needle pegs.  Gauges are not for anything but verification and seeing trends develop.  Install "idiot type" sender units that switch on(make contact) when alarmed.  That means the water temp alarm unit goes to ground when over temp is sensed and the oil pressure sw goes to ground when the oil pressure drops below acceptable limits.  You can run these all in parallel and to a single red light AND A LOUD ALARM but install a "cut out switch so you don't get and alarm for low oil when starting.   On that cutout posit have a large red light to alert you to the system being bypassed.  Test it by switching on the engine power with the disable.

If you are running a 2 Stroke with two thermostats you should have a temp sensor and alarm for both heads.

Admittedly, I am sort of anal on this topic.

Good luck,

John

[Sean]

...  That means the water temp alarm unit goes to ground when over temp is sensed and the oil pressure sw goes to ground when the oil pressure drops below acceptable limits. ... run these ... to a ... LOUD ALARM ...

Actually, I disagree with all of this in the present situation (generator coolant temperature).  Rather than using up a good coolant sender location for a sender for an alarm that should, by rights, never sound, you should use (or, more precisely, the generator manufacturer should have used) that location for a two-wire, normally closed sender wired into the "run" circuit.  When the temperature reaches the set point, the contacts open and the generator immediately shuts down.  A similar switch, with normally open contacts, is used for oil pressure; when the pressure drops below a set point, again the contacts open and the generator shuts down.

You need to use two-wire senders for this purpose, because you want the fail-safe shutdown circuit to be power-to-run (meaning any loss of power causes a shutdown).  Most diesel generators include these common safety shutdowns as a matter of course.

A grounding sender for an alarm and light is a good idea for engines you can't allow to shut down inadvertently, such as the main engine.   Many buses commonly came equipped with Kysor modules to do exactly what you described (gang several fault conditions into a single light and buzzer or bell).

I am presuming the the OP's generator has two coolant senders; one would be the shutdown as I just described, and the other would be the sender for the gauge.  It is this latter sender which would get replaced with one made to drive a dual-gauge setup.

FWIW.

-Sean
http://OurOdyssey.BlogSpot.com

[JohnEd]

Sean,

I don't disagree with anything but your crit of me.  Your info only augments and compliments what I said.  All the systems, and mainly the older ones, didn't come with the level of sophistication that you mention.  Not that they all couldn't be modified to utilize all of the circuits that you noted.  We were talking about gauges for monitoring performance.  Emergency shut down circuits are a different topic.  I offered ideas on achieving that level of monitoring utilizing all of the extant equipment/gauges/senders in the current design and my advice was germane and possibly of use.

Lets look at this as three topics about the same equipment.  Those topics would be:

1) Monitoring with remote sensors and indicators.

2) Alarming with visual and auditory devices

3) Emergency shut down

I was referring to topics 1 and 2 and you seem to have  been into topic 3.  I agree with you on what you said about equip protection auto shut down devices.  I also don't see what I said about meters as in any way a repudiation of what you said.  You have often seemed, to me at least, to come out of the chocks with a resounding "YOU ARE NOT CORRECT" and in this instance, as others I have noticed, you are not justified in saying that even in the technical sense.  Sometimes you seem to be playing "gotcha".  The game is actually "How do we create the best and most full advice for any situation".  Not who did it or what degree(academic, not Fahrenheit) is at hand.

I would suggest you read DaleCarnegie but I suspect many before me have already done so.  Certainly I could be faulted for not utilizing his sage advice in this particular instance but I feel driven to baser approaches and I am sure you have been spoken to in velvet tones that haven't apparently gotten through.

Take this as on topic and clarification and intended as completely positive in tone and message.

Your friend,

John

[Sean]

I don't disagree with anything but your crit of me.

John, I did not intend to "criticize" you and I am sorry you read it that way.

Please go back and read my very first line: "Actually, I disagree ..."

That means just what it says:  I disagree with the recommendation.  Disagreement is not criticism.  Later in the same post I agreed with you that this was a good idea for engines that can not be automatically shut down, for whatever reason.

I stand by my disagreement, on many grounds, principally human factors.  I think it is a bad idea to have an alarm bell or warning light at the driver seat for a generator when, for the same effort to make such a circuit, a proper safety shutdown could be implemented.  That's an opinion (different from yours, apparently), and I thought I was clear about that.

-Sean
http://OurOdyssey.BlogSpot.com

[JohnEd]

Sean,

Perhaps my sensativity to your "disagreement" stems from how highly I esteem you professional opinion.  I was in a reactive frame of mind when I read and answered your post.  Even at that I now think I over reacted and extend the apology you deserve.  I'm sorry, Sean.

Back to bidness:  What do you say to splitting this sort off topic up into the three subsets I proposed?

*
Actually, I disagree with all of this in the present situation (generator coolant temperature).  Rather than using up a good coolant sender location for a sender for an alarm

For clarity, I never proposed giving up the temp sender hole for anything.....I think we can have our cake and eat it too. Just takes a smidgen of engineering, mostly.

I have always used a single wire sender where the sender was NO and went to ground.  That design, one that predominates in the industry, is deficient in that a broken wire defeats the alarm. a ground, on the other hand, will alert you to the circuit failure.  I incorporated a Bosh 30 amp relay(for overkill) into my circuit so I got the two wire system but only ran one wire into the engine bay.

Little emergency so I'llhave to finish later