Connecting two sprinkler controllers to one system

[sunknee]

I searched the web but could not find an answer to my question. Perhaps someone could help me out with this one.

I purchased a serial RAIN8net and expansion module. I have an existing Rainbird controller in my garage and would like to keep this connected as well so the sprinkler company can use it to easily service/test my zones. I would like to connect both of these controllers to the same zones so I could use either the Rain8net by computer or the Rainbird controller manually. I would not be using the Rainbird to run my irrigation schedule of course (that is why I purchased the Rain8net).

I sent this technical request to RAIN8 tech support first. As I understand from RAIN8 tech, there is a big problem connecting both controllers in parallel. If the phase of one transformer is not in phase with the second, a dead short will occur and destroy both controllers. Next I asked RAIN8 tech if they thought I could just connect all zones together except the common line and switch that one only by a non-shorting toggle or relay (could do this with my ELK M1 and the relay board). This will not allow a complete voltage circuit to the other controlled. They thought that may work and stated be sure and test it by reversing the connections on one transformer.

Next, I sent this to my Rainbird Controller tech support and they replied:
"I think you have a good understanding of the danger of sharing common wires.I can not recommend your solution, except to say the circuits should never actively share each others common. What ever solution you decide on, be sure that if the switch was to fail, it would not fail by shorting the commons together."

Any comments would be appreciated.
Thanks,
Sonny

 

[BraveSirRobbin]

Do you have the capability now with your Elk or anything else to detect wireless X-10 signals? Do you have a PC and/or automation software connected to something that can receive X-10 (is this PC also connected to the Rain8?)? If so get a Palm Pad remote and have your landscapers check the sprinklers that way (this is what I do while troubleshooting my sprinklers, works out great).

If not, maybe consider getting at a minimum an RR501 and PSC05 so you can receive a signal from a palm pad. Of course an MR26a or W800 receiver tied to an Elk via a serial expansion card would be optimal, though a lot more expensive.

I would recommend against running parallel relays as you bypass the internal limiting clock of the Rain8.

 

[sunknee]

Thanks BraveSirRobbin. Using the Palm Pad remote is another option. I have a few of those. As for bypassing the internal Rain8 clock, I would keep the RAIN8 connected to the sprinkler setup 99% of the time by switching the common sprinkler controller wire to the RAIN8.