relays failing??

[Steve]

I use the M1RB with 4 valves and it works great. I'm sure it will also work with the M1XOVR. The relay boards are just so much neater to use than individual relays plus they have power LEDs, etc. If you never need a relay for anything, then I guess I could agree on a dedicated controller like WGL, but if you will ever use a relay for anything else, the relay boards are definitely the way to go over 912's imho.

 

[brotsten]

I use the M1RB with 4 valves and it works great. I'm sure it will also work with the M1XOVR. The relay boards are just so much neater to use than individual relays plus they have power LEDs, etc. If you never need a relay for anything, then I guess I could agree on a dedicated controller like WGL, but if you will ever use a relay for anything else, the relay boards are definitely the way to go over 912's imho.

I agree, kinda. I have an M1XOVR board, but I have two remote locations I failed to run some 18 gauge, only Cat5. In one, I have a single watering valve and in the other I have a whole house water shutoff valve. The little 912's are perfect for this.

Brian

 

[jlegault]

Using an OVR and RB (912 also worked fine). OVR is about 100 feet from the M1, using Cat 5.

Problem I had with Homeseer killed a relay (Output hang) on the OVR

http://m1sprinkler.blogspot.com/

 

[BraveSirRobbin]

The problem here is not if those other techniques would work, the problem is that the OP purchased the 912 relays thinking they would work, now they don't and he is having to pay additional money for an alternate solution! I guess he could place a transistor in front of the coil, but what a hassle...

 

[wired-up]

Thanks everyone for their input:
I would have put in a M1XOVR if I could have gotten one this weekend, but I really needed to fix this without increasing my expenditure, and I needed to reliably water the new sod.
I tested a lot this weekend and ran about 35 cycles of the irrigation system (short 1 minute/valve). As my setup was, with 30 feet of Cat5e carrying the ouput from the elk to the relays, the relays were very irratic. almost never did they all fire sequentially, and all failed some of the time.
Spanky was right (of course he was, he's the Chief) it was the lack of appropiate power getting to the relays. I measured 11 volts at the wires at the relay end, but voltage was only about 7.3-7.5 when the relay was connected and getting power, whether it activated the solenoid or not (needs 9 v to activate per specs) as there is resistance in the relay.
WayneW asked about the type of wire and the length of the run. I'm sure someone knows how to calculate loss over distance for a given gauge wire. I was able to shorten my run of cat5 by about 10 feet and now measure 8.9 volts at the relay when activated instead of 7.4, and after 15 trials, there has been no failure in any relays.
Lessons learned:
1. Spanky is always right.
2. The folks at cocoontech are incredibly helpful.
3. Cat5 is great for moving data, but not great for supplying voltage
4. If you are using a relay for a critical circuit (water shut-off, for example) and it is at a distance from the elk, measure the voltage with the relay activated to see if it will work all the time (the irratic nature of my setup drove me crazy)
I'm still a little nervous as I'm just under the 9volt minimum, so I'll probably do something else later. For now I will watch carefully. I may try to figure out a way to use some of my spare water detectors to make sure each zone really works.
Thanks again for all your input.
If you want to laugh at another of my adventures (goof-ups) with this sprinkler testing check out my post in the "M1 dialer timing issue" thread in the Marketplace-->Elk Products forum
David

 

[politics123]

So... I've been following this thread with interest, since this is next weekend's project.

For those of us not so ohm and voltage intelligent, let me repeat it back to you just in case I misunderstood...
1) It would seem there are two options to implement the "pool man's watering system"

a) However, we only have one schematic posted -- perhaps we can get a schematic using the OVR?)
I'm not sure yet whether one solution is better or not. Can we get a summary for which solution is better (or, more likely, the pros/cons of each)
​

2) You shouldn't use cat-5 cable to the relays (if you use relays)

Thank you!

 

[Steve]

WayneW asked about the type of wire and the length of the run. I'm sure someone knows how to calculate loss over distance for a given gauge wire. I was able to shorten my run of cat5 by about 10 feet and now measure 8.9 volts at the relay when activated instead of 7.4, and after 15 trials, there has been no failure in any relays.

That seems like a big drop to me for only 10 feet even though Cat5 is only 24AWG. I like this site for calculating good 'rule of thumb' data. If you have a kink or something in the wire, that could also impact it. Replacing that Cat5 with 2 runs of 18/4 would probably help alot (unless the Cat5 is tied down, you could use it as a pull string to pull new larger wire). I think it also makes a difference where you place the relays. If you put them by the Elk (closer to the outputs) instead of at the far end by the valves, I think that may may a difference. My M1RB is setup pretty much the same way. The RB is in the can by the M1 and the 24V is at the old outside box. About 75 feet of Cat5 and it works fine (never took any measurements).

 

[BraveSirRobbin]

I was able to shorten my run of cat5 by about 10 feet and now measure 8.9 volts at the relay when activated instead of 7.4

I agree with Steve. Seems to me you should only get around two tenths of a volt or so drop if using 100 ft of Cat5e cable as those relays are only pulling 30 milliamps of current, unless of course that relay data sheet is another case of incorrect specifications listing...

Did you ring out your wiring with a multimeter as I suggested in a prior reply above? Something isn't adding up here...

 

[wired-up]

I agree with Steve. Seems to me you should only get around two tenths of a volt or so drop if using 100 ft of Cat5e cable as those relays are only pulling 30 milliamps of current, unless of course that relay data sheet is another case of incorrect specifications listing...

Did you ring out your wiring with a multimeter as I suggested in a prior reply above? Something isn't adding up here...

yes I did follow your instructions and the wiring was fine, no shorts, checked all connections. Maybe when I re-ran the wire I inadvertedly fixed something?? My meter is a cheap one that doesn't measure amperage unfortunately.
I like Steve's idea of using the cat 5 as a pull cord to replace with higher gauge. I'll have to check my pre sheetrock pictures to make sure that's possible. I put all my other relays in the box with the M1, but I didn't think it was a good idea to do that with the irrigation valves and run the 24 volts through the cat5 to the garage. Or is it? what do you think? Thanks for the link about the rule of thumb, I may learn a little about electricity yet. (Can anyone recommend a good book for basics?)
David

 

[Steve]

I put all my other relays in the box with the M1, but I didn't think it was a good idea to do that with the irrigation valves and run the 24 volts through the cat5 to the garage. Or is it? what do you think?

That's what I have. Wall wart is in box outside where old controller was. Relays back in can. Connected via around 75 feet of Cat5. Should be fine for running 1 valve at a time. I've even had 4 on once during a bug in programming and no meltdowns, but I wouldn't have more than 1 on at a time for any length.

 

[wired-up]

Steve,
It sure would simplify matters if I can put the relays back at the M1 in the can. Looking at the link to rule of thumb you posted, it says max amperage for power transmission for 24 gauge is 0.577. My wall wart is 24 volts, 1.67 amps. Would that be too much for the cat 5?
David

 

[Steve]

The wall wart can supply that much but I think the average valve is around .35A max, so thats all that should be drawn thru the wire assuming you only have 1 valve on at a time. Mine has been that way for a year a so and no meltdowns yet. I can't swear that it is proper or anything, but it works for me. Certainly 18ga wire leaves no doubt but I think Cat5 is ok, especially for shorter runs.

 

[Spanky]

As the current on the output increases, more voltage will be dropped across the protection resistor, thus providing less voltage to the coil of the relay. The relays tend to vary in current from the manufacturing process as well as the transistor gain that drives the +12V. If a relay is working, the voltage across the relay coil will probably be above 8.5 volts.

The protection resistor is on the M1 control board to keep someone from dead shorting the output and blowing the driver transistor.