SignalTraffic Forums

by **DigitalMCO** on Sun Jun 02, 2013 5:23 pm

A while back I opted to add an MMU, (EDI MMU-16E) on my 8-phase cabinet. The back panel in question had been modified to work without an MMU but was wired up to run with one. I figured an MMU would complete the “look” of my cabinet so I figured why not add one. I’ve been dealing with someone who has been more than helpful in trying to isolate my problem regarding the MMU, however I thought I’d open it up to the entire group to see if I was missing something obvious.

The error I’m getting is a conflict between channels 2 & 4 with the Red, Yellow and Green flashing on 2 and only the Green flashing on 4.

The Load switch layout is as follows:
LS1-2V South Thru Vehicle
LS2-2P South Ped
LS3-4V East/West Vehicle
LS4-4P East/West Ped
LS5-1V North LEFT
LS6-5V South LEFT
LS7-6V North Thru Vehicle
LS8-6P North Ped
*All unused load switches have been given jumpers so as not to cause a Red Fail.

The four jumpers on the MMU program card are:
1-5
1-6
2-5
2-6

I can also confirm that the MMU I'm using was in working condition with no known problems when I received it.

Any help you can give me is as always greatly appreciated.

Thanks :wave:

by **EPAC-EPIC-MARC** on Sun Jun 02, 2013 5:36 pm

Are you using one of Joes backpanels? Your going to have issues because the load switch layout isn't standard. MMUs operate with Load Switches 1 through 8 being vehicle, and 9 through 12 as peds 2,4,6,8.

For example, Load Switches 2 and 4 are normally vehicle channels 2 and 4. Because you are using channel 2 for a ped, and yellow is lit do you have a resistor tied to the yellow load switch output?

Does channel 4 cycle properly, is channel 2 static R Y G on all at once?

Trying to narrow down the possible issues

by **EPAC-EPIC-MARC** on Sun Jun 02, 2013 5:38 pm

Also, the way your MMU is set up you should be getting a conflict from the get go.

If Load Switch 1 is South Vehicle Thru, and Load Switch 2 is South Ped, 1 and 2 cannot come on together. Its not jumpered on the program card to do so.

by **TacomaJoe** on Sun Jun 02, 2013 5:59 pm

Although the loadswitch to phase associations is changed, so is the monitor wiring:
LS1-ch2
LS2-ch2ped or MMU ch9
LS3-ch4
LS4-ch4ped or MMU ch10
LS5-ch1
LS6-ch5
LS7-ch6
LS8-ch6ped or MMU ch11

The MMU should drop into 12 channel mode and work fine. I would lean towards a bent wire/terminal that's mixing things up. Something to look at would be when it trips, match the controller display and the loadswitch indications up with what the monitor says. With a 2-4 conflict, read the controller to see which one should be on, look at the loadswitch LEDs to see what the controller is trying to turn on.

by **EPAC-EPIC-MARC** on Sun Jun 02, 2013 6:15 pm

TacomaJoe wrote:Although the loadswitch to phase associations is changed, so is the monitor wiring:
LS1-ch2
LS2-ch2ped or MMU ch9
LS3-ch4
LS4-ch4ped or MMU ch10
LS5-ch1
LS6-ch5
LS7-ch6
LS8-ch6ped or MMU ch11

The MMU should drop into 12 channel mode and work fine. I would lean towards a bent wire/terminal that's mixing things up. Something to look at would be when it trips, match the controller display and the loadswitch indications up with what the monitor says. With a 2-4 conflict, read the controller to see which one should be on, look at the loadswitch LEDs to see what the controller is trying to turn on.

Ahh ok, I didn't know that the monitor wiring was changed to reflect the new switchpack arrangement. I would also check your wiring and connections for improper/loose hookup.

Throwing this out there...Type 12 mode will run when the MMU is not talking to the controller via the SDLC port. Its a backwards compatible feature to use on a TS-1 controller system. Type 12 / TS1 have a walk output wire on every channel. R Y G and W. TS-2 mode eliminates the walk wire, and uses R/D, Y, G/W. I never used Type 12 mode so I have to ask if the different modes require different wiring hookup for the walk monitoring?

by **2070** on Sun Jun 02, 2013 9:03 pm

Did it ever work in your cabinet, or problems since day one?

Use another switch pack in 2

Check the heads on SP-2 for a loose neutral/walk out.

Disconnect the ped head(s) on SP-2 and use 3 light bulbs. 1 on each color output and to neutral. If that works take the yellow one off, If it trips then you have a "Yellow Inhibit" jumper on the MMU that should be looked at, Joes says SP-9.... On the card.

by **DigitalMCO** on Sun Jun 02, 2013 9:55 pm

Success!

I swapped out the switch pack, still no change. So I went with Phil's suggestion and ran a different signal to the offending channel and Voila! it started working upon power up. I'm not sure if there was a loose connection somewhere or a questionable LED module in the original signal head, but now everything seems to be running smoothly.

Thanks for everyones help on this. :good:

by **TacomaJoe** on Sun Jun 02, 2013 10:17 pm

The usual problem when you're looking at at G-Y-R indication is an open neutral. We run all our cabinets in the shop with a resistor loaded LED display panel. They run fine in the shop. When you toss in cables and signals there is plenty of room for mix ups.

by **EPAC-EPIC-MARC** on Sun Jun 02, 2013 10:32 pm

Glad you got it straightened out Ron! Loose or open neutrals have plagued me in the past too. In my case i overthink the problem and rip everything apart to find out it was single loose wire! :crazy: