Last night I started adding more to my signal system — after a long time. Building a signal bridge with BLMA heads and styrene plastic ... three heads for three tracks.
I built one head and plugged in to an existing SE8C ribbon cable via the SMBK board.
I already have one signal on this SE8C “channel” which is connected to Red Hi/ Yellow Hi/ Green Hi/ Common Hi — so I connected the new one to Red Hi/ Yellow Hi/ Green Hi/ Common Lo. The orientation of the connector is the SAME for both signals, so I expected the new one to respond on a different address.
It didnt! The Common Hi and Common Lo were both bound to the same address (263/264). I am a bit stumped ...
NP.
The Commons I believe are indeed common, so you'd get your 4 sets of signals heads from the Red/Yellow/Green(RYG) Hi & (RYG) Lo pads, and then with the SMBK spun in the socket, RYG Hi and RYG Lo. Swapping the commons I do not believe changes the result.
The Terminal breakout kit does function differently. I struggled with a friend setting up signals on a module as its not wired the same way as the Signal Head breakout kit.
-mike
Sounds like you DON'T have the connectors in the same orientation. That's the only way this could happen - connector on the wrong way, pin 1 becomes pin 10 and vice-versa. If you used colored ribbon cable, if both SMBC's are plugged in the SAME way, then they both will have the indicator mark pointing at the same color wire, either both black or both brown. There's an arrowhead on the board, also pin 1 is indicated with a square pad where the connector is soldered on.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy,
Thanks for your response ... I was hoping you will jump in here. But -
I moved the new signal Common to Common HI (ie wired to SMBK exactly like the existing signal. And No change! Same "duplication problem" ... your theory would have been correct if that changed the address.
So-
Really stumped. Haven't reset command station yet, maybe that will help.
Neeraj
What happens if you try the test mast as mentioned in the quick test section of the instructions? Turning it to face the opposite direction should make it respnd to the next 2 addresses.
Wait - I knew something seemed odd - 263/264 are the addresses for head C in the BC orientation already - using common high. Switching pin 10 to pin 1 - or just reverseing the connector, should make it respond to 257/258 or 259/260 - if you just move the common wire it should go to 267/258 but if you flip the connector in the socket it should move to 259/260.
Unless you are really really sure you will never need a second SE8C, I would change the board address from the default.
Hey NP-
My help almost always adds confusion, so I will try to not muddy the waters too much . . .
Does your OP state that you have two wires connected to each of the red-hi, green-hi, and yellow-hi terminals? And one annode to the common-hi and another annode to the common-lo? Anything connected to the red-lo, green-lo, or yellow-lo terminals?
Each SE8C driver will control four heads via 10-conductor cable, and each TSMK will control two heads. It doesn't really matter which is high or low on the mast.
Robert
LINK to SNSR Blog
Randy-
Correct. The existing signal mast is C in the BC orientation. It’s a single head, on one SMBK. Red Hi/Yellow Hi/ Green Hi/ Common Hi.
The second SMBK was plugged into the ribbon in the same orientation, and it was Red Hi/Yellow Hi/ Green Hi/ Common Lo. I expected it to respond on 257/258. It didn’t. Still respond on 263/264.
Even though the orientation is correct, I suspected that I messed something up somewhere. So, I switched Common Lo on the new signal to Common Hi, and GOT THE SAME RESULT. I.E. Both signals responding on 263/264.
Before I started on this, I first tested that all 4 addresses were responding using a test SMBK (so far uncut). It worked fine on 257, 259, 261, 263. Of course had to be plugged in two orientations to test all addresses. So I don’t think the SE8C is the problem.
This afternoon I should get some time to review this.
Robert-
It is a confusing topic, and any help is appreciated. You are correct ... I have two signals wired to the same RGB, but anode is wired to Hi in one case and Lo in the other. I am not using TSMKs on this one, I do have a TSMK based install ... in a different place and one SE8C channel it is nicely driving 4 heads fully independently based on JMRI logic.
Thanks
Try one that works on 263/264 and just turn the plug around, make NO wiring changes. See if it goes to the other address.
Or possibly try another channel. Or the standard SMBK on the problem line to verify it's working correctly. It's acting like it's not multiplexing between common low and common high, but I think that would affect all channels, and the only wat that's going to happen is if there is a short between pin 1 and 10 in the ribbon, which is next to impossible, or the microcontroller is blown. You ARE using resistors, right?
Resistors are built into the SMBK and the TSMK.
There could be a short in the cable if the plastic plugs were squeezed down a little crooked.
My first thought was to check and double check to make sure the arrows for pin 1 are aligned. My second thought is to wire one signal head to the red/green/yellow-hi to the common-hi and the other signal head to the red/green/yellow-lo to the common-lo. Then see if the multi-plex signal is separating before reaching the terminals.
1. Yes, using resistors which come with the SMBK
2. I was just thinking of the short. I am going to test now.
The problem is, the short for these symptoms would have to be between pins 1 and 10, which are opposite sides of the cable. Yes, putting a connector on crooked could short adjacent pins - but one side to the other just isn;t going to happen.
rrinker The problem is, the short for these symptoms would have to be between pins 1 and 10, which are opposite sides of the cable.
Unless it was intentional. I have no idea why Digitrax would do this, but on the two SMBKs I have, Pin 1 is connected to both Common Hi and Common Lo pads. (they are solid short). Pin 10 is not connected to ANY pad, but on the front side, there is one place a trace from Pin 10 comes up to a small solder pad (next to the resistors you see a pair of pads on the front side .. one is Pin 1 and one is Pin 10.
So, on my signal bridge -- I disconnected the anode from Common Hi/Common Lo and connected to this tiny pad of Pin 10. Voila! I could address the head. Now I have to do two more heads and I will check if all works OK.
The question is, when I tested ... I was able to test both A1/A2 and B/C orientations on the SMBK I have ... and this layout error did not matter. I am still stumped by this ... I have to think more.
My other set of 4 signals is based off of a TSMK ... and I had no such trouble when I wired four signals to it. I do not have a TSMK handy right now otherwise I would have checked if this problem exists there.
NP01 I am still stumped by this ... I have to think more. NP.
I am still stumped by this ... I have to think more.
I'm stumped too, but I don't think thinking about annodes will get you anywhere. I use NJI double-head signal masts and there is only one common annode wire, and it connects to the common-lo terminal. I use TSMK connectors, but I think the SBMKs are the same. Namely, that the multi-plex info is differentiated by the SE8C through the R/G/Y leads, and that the common-hi and common-lo are common. I think the colored leads are the issue, not the positive grounds. Maybe.
Common-hi and common-lo definiutely are not common to one another, look at the diagram in the SE8C manual. The top and bottom 3 LEDs will swap if you flip the connection over, and what was pin 1 will connect to pin 10 and vice-versa. If the common-hi and common-lo were the same thing, then the top head of the A signal would show the same aspect as the C or siding signal on the B/C side. ANd you wouldn't need a second pair of addresses. The SE8C multiplexes on each line by alternating between common-hi and common-lo. The value set in one pair of CVs controls what is put on the 8 pins when common-lo is active, and the other pair of CVs controls the 8 lines when common-hi is active. Calling them common-lo and -hi is probably a mistake as it confuses them with the 4 hi and 4 lo lines which reference which head on the mast is being controlled. The common-lo and -hi really reference the orientation, not the top vs bottom head.
Yes, the SMBK and the TSMK are effectively the same. I did go back and notice you said uncut SMBK - does the one you are connecting your signals to still have the stock LEDs connected as well? That could be a problem.
Also, as you sure you have the wires from the signals themselves correct?
rrinker ... Calling them common-lo and -hi is probably a mistake as it confuses them ...
Amen! It actually took me a while to understand how two sets of RGB lines can drive four signals. Digitrax could have been clearer in their documentation.
rrinker ... I did go back and notice you said uncut SMBK - does the one you are connecting your signals to still have the stock LEDs connected as well? That could be a problem ...
On the new signal I am building, I cut the mast before attaching a painted styrene tube on it. I tested Common Lo/Common Hi short on both the uncut test mast and the cut mast for the signal bridge being built.
rrinker Also, as you sure you have the wires from the signals themselves correct?
Definitely. I now wired a second head: Red Lo, Yellow Lo, Green Lo and my own "Common Hi" wire (not the SMBK pad) ... working perfectly on 257/258. If the LEDs weren't wired right, the four states would not match expected colors.
Next up will be Red Lo, Yellow Lo, Green Lo, Common Hi (existing pad) and that should get 261/262. Then I would have a working signal bridge -- but no explanation for why it works! Too late for soldering now, so I will work on this in the morning.
NP
I think I got it. Digitrax took a shortcut on SMBK. You see, A1 and A2 both use Common LO but pins 4,6,8 (A1) and 3,5,7 (A2). B and C both use Common HI with the same pins 4,6,8 (C) and 3,5,7 (B).
When you are in A1/A2 orientation, Pin 1 on the SMBK is connected to Pin 1 of the ribbon cable, and BOTH the Common Lo and Common Hi Pads are connected to Pin 1 of the ribbon cable which is linking to Common LO on the SE8C. Doesn't matter because you can address both signals using the same Common.
When you flip the orientation, Pin 1 of SMBK connects to Pin 10 of the ribbon cable, and this combined common line is driven by Common HI (Pin 10 of SE8C).
So ... this layout issue does not matter, so long as your SMBK is using only 2 signals where both are using same anode and seperate sets of cathode.
Soon as you need same set of (3) cathodes and different anodes, you have a problem.
I wish they didn't do it this way. I need to design an SMBK-Advanced where things will be much easier.
Hmm, interesting. It doesn't LOOK like they have the two connected anywhere, but then it's hard to follow circuit board traces from an illustration in a user guide.
NP01 When you are in A1/A2 orientation, Pin 1 on the SMBK is connected to Pin 1 of the ribbon cable, and BOTH the Common Lo and Common Hi Pads are connected to Pin 1 of the ribbon cable which is linking to Common LO on the SE8C. Doesn't matter because you can address both signals using the same Common.
This is true.
NP01 So ... this layout issue does not matter, so long as your SMBK is using only 2 signals where both are using same anode and seperate sets of cathode.
Also true.
NP01 Soon as you need same set of (3) cathodes and different anodes, you have a problem.
True, but not really a problem; you just need another SMBK (or TSMK, and as you probably already know, the TSMKs are easier to piddle with). Then the issue becomes limited by the ten wires in the ribbon cable. There are higher-count ribbon cables and pin connectors available if you want to freelance something.
Good luck. Sorry I wasn't much (or any) help.
Thanks Robert and Randy. Finally assembled the entire bridge and soldered and programmed. Right now no YELLOW indication because the following block is not signalled fully and I need to read the state of the next signal (=RED) for Yellow indication. Glad this is working! Was drivnig me nuts for a week!
Robert, you are right TSMKs can be easier, but you do need a breakout board. TSMK itself isn't good for directly wiring to the signal heads. I installed a TSMK next to four 6p/6c phone outlets and wired it so that I could plug in signals. I have did this five years ago so I have to reverse-engineer it a bit. This works well when you have one head per mast signals.
By the way, below is the hack I had to do to access Common Lo when SMBK is plugged into the BC orientation. See the white wire. And no, please don't comment on my poor soldering skills.
NP01 By the way, below is the hack I had to do to access Common Lo when SMBK is plugged into the BC orientation. See the white wire. And no, please don't comment on my poor soldering skills.
Hey, I have no comments about your soldering skills. None at all. I know just how small those solder pads are. I took one look and chickened out immediately. Hence, the TSMKs.
Glad to see you can put this in the finished pile.
OK I give up, none of this makes any sense. I wonder how Digitrax is number the 10 pin connectors. If you have saw the black wire on the right, and the connector facing up, NORMAL pinoust for that would have the right rear as pin 1, connectec to black, the right front would be 2, the alternating back to front (odd numbers on the back, even on the front) so the left front pin would be pin 10, on the brown wire. The result matches all the other pins as shown in the SMBK instructions, but the two pins that have traces that run up to the pads marked for common lo and common high are NOT the ones that would be pin 1 and pin 10, they are 2 and 9.
Again this is trying to trace from the photo in the instruction sheet, so maybe they are getting away from me, but if you hold the SMBK so that the resistor side faces you, the left front pin should be either common high or common low, and the right rear pin should be the other one (simple continuity check if you have a spare SMBK).
You have to follow a couple of vias, so not straightforward to follow in the picture. Pin 1 goes to Common Lo and Hi. Pin 10 goes to the "tiny pad to nowhere" ... I just don't know why they lied about this. I will call them, but I am usually pretty busy during work hours so might not get to it.
I did not trace 2 and 9, they are AUX LO and HI, and are "reserved" anyway. But it now that you have got the pin numbers in your head -- 3,5,7 and 4,6,8 are mirrors of each other in the middle part of the connector. Whichever way you plug the mast in, the pair of signals you get has independant cathods and both have the same anode. So the short does not matter.
Interestingly, because they floated Pin 10 ... the Pad 1/Pad 10 short on the SMBK does not propagate over the ribbon cable and mess up the entire channel. Now I really have to talk to the engineer who did this.
Funnily enough ... there are a couple folks here on the forums who have used SMBKs are mast bases and installed them using SMHK (signal mounting hardware kit). I was wondering how they didn't have a problem. I guess they never tried to drive 3 lights from one SMBK ...
I don't like to do tons of signals (cost, wiring) so I have deviated from the American prototype and designed my own signalling scheme. At some point I will post my signalling rules ...
Oh, I was seing the vias, and since the conveniently provided pictures of both sides with it flipped over it wasn't too hard. The pad where you soldered the jumper wire to seems to correspond to a via on the other side.
However - if common high and common low pads are tied together on pin 1, then if you flip the way it's plugged in to the ribbon cable over, pin 1 becomes pin 10 and you should get the common lo on both of those pads. 1 becomes 10, 2 becomes 9, 3 becomes 8, etc.