What's New on the PRR Panhandle Division?

[gtfan]

How do the DZ-2500s get their TMCC signal? Do they have antennas or do they get it directly from the outside rail?

[jlong]

George, have you considered a "Moon Amtrak" scene?

[G3750]

How do the DZ-2500s get their TMCC signal? Do they have antennas or do they get it directly from the outside rail?

GT,

The DZ-2500s get their TMCC signal from the Command Base via something called the DZ-2001 Data Wire Driver (rightmost label on the diagram). That component plugs into the Command Base and sends the signal down an accessory buss. See the top edge of the diagram below.

20091116_Panel.jpg (100.49 KiB) Viewed 4074 times

The buss runs all over the layout and provides the TMCC signal to each of the 21 switches machines.

George

[J. S. Bach]

Updated 12/17/2013:

From the "Two Steps Forward, One Step Back" department:

I started re-installing the new replacement DZ-2500C switch machines on the layout last night and encountered some bizarre behavior.

http://ogrforum.ogaugerr.com/topic/biza ... tmcc-issue

I'm not really sure what's going on, but I've got e-mails out to the manufacturer and some gurus. If I don't hear back from anyone, I'm going to install the next switch machine in the string (no. 19) and see if the problem "jumps" to it. This is very strange, but there has to be a logical reason for it.

George

I am enjoying reading all of the responses that you have gotten.

[jlong]

I am enjoying reading all of the responses that you have gotten.

It's way over their heads. Not even Barry or Dickle have an answer.

[G3750]

I am enjoying reading all of the responses that you have gotten.

It's way over their heads. Not even Barry or Dickle have an answer.

Well, the reason you haven't seen the responses on the forum is because they have been e-mails. I've been talking to the company owner for Z-Stuff and an electrical guru on the West Coast who dabbles in add-on TMCC devices and electrical troubleshooting.

Yeah, the forum response has been "crickets" and I was expecting something.

The DZ-2001 is a serial device driver. And all the devices (DZ-2500C switch machines) on the data wire are low speed. The only limit of the device that I might be exceeding is the length of the wire (30-40 feet). That's because I am running a loop around the entire layout. If I shorten the loop and add another, I might be OK. I'm still thinking about it.

George

[Roy]

"Background:

1.This layout is all TMCC - no Legacy.
2.I recently replaced 5 flaky DZ-2500A switch machines with new DZ-2500C machines.
3.These are located in my lower level hidden storage yard (naturally ). Switches are supposed to work via both CAB-1 and pushbutton (DZ-2502P).
4.The switches were all reprogrammed off the layout using a spare Command Base, 15 VAC tap from a K-Line PowerChief 120F transformer, and a brand new DZ-2001 Data Wire Driver. All programming went well and these switches (numbered 17-21) throw correctly via CAB-1. At the time, they were not tested using the pushbutton.

The Problem:

1.I installed Switch No. 17 back onto the layout and added power. It would not throw using the CAB-1 remote but would operate via pushbutton (DZ-2502P). Some other switches (DZ-2500A's) that had been working for years would also not work via CAB-1. Some would. Pushbuttons seemed OK. After cycling the power and trying this again several times, all functionality returned to all switches (including the new No. 17).
2.Feeling like the gremlins had been banished, I then installed Switch No. 18 back on the layout and added power. Same behavior. Works using pushbutton but not via CAB-1. All other switches (including No. 17) work fine both ways. This has still not resolved itself."

This is not my department, but I'm wondering if all the new switches need to be physically installed, and the system restarted, in order to be recognized by the TMCC (and the CAB-1's)?

[gtfan]

Some things I would try to help isolate the cause:

1. Replace the data wire driver with the new one that you programmed the new switches with. Is it the same model as the "production" driver? Maybe there is a difference that makes the new driver more compatible with the new switch machines.

2. Remove one or more of the "old" switch machines temporarily to see if the newest one starts working. This could indicate a load issue on the data wire driver.

3. Try running a wire directly from the DZ-2001 to the new switch machines. If wire length is the problem, perhaps running more of a "star" configuration rather than a long bus network may help. There should be no timing issues as there doesn't appear to be any response from the remote devices, and it even states in the documentation that you can have multiple machines on the same address, indicating that each switch machine is "receive-only."

[jlong]

George, did you try magic lamps???

[G3750]

[This is not my department, but I'm wondering if all the new switches need to be physically installed, and the system restarted, in order to be recognized by the TMCC (and the CAB-1's)?

No, I don't think so, but thank you for the suggestion. I am installing in numerical order, by the way. And Switch No. 17 is now recognized by TMCC.

George

[G3750]

Some things I would try to help isolate the cause:

1. Replace the data wire driver with the new one that you programmed the new switches with. Is it the same model as the "production" driver? Maybe there is a difference that makes the new driver more compatible with the new switch machines.

That's a possiblity, but a very low probability of a fix. Still, I will keep it in my back pocket...

2. Remove one or more of the "old" switch machines temporarily to see if the newest one starts working. This could indicate a load issue on the data wire driver.

Based upon speaking with the manufacturer and confirming my meager knowledge of RS-232 serial protocols, we would need 5x more switch machines to create a load issue with the data wire driver.

3. Try running a wire directly from the DZ-2001 to the new switch machines. If wire length is the problem, perhaps running more of a "star" configuration rather than a long bus network may help. There should be no timing issues as there doesn't appear to be any response from the remote devices, and it even states in the documentation that you can have multiple machines on the same address, indicating that each switch machine is "receive-only."

This is an approach that I may try sooner rather than later. Wire length might be an issue. But right now, I am exploring a potential programming mode with the manufacturer.

Thank you for the suggestions. More when I know it. My schedule gets a little hectic between now and Saturday. I'm hoping to get to this sometime Saturday.

George

[bluelinec4]

George
We ot rid of the DZ-2500's because of their problems Went back to the DZ-1000's which are much more reliable. We had 60 DZ-2500's on one data wire driver. We had them wired for TMCC and also DCS operation (DCS using the non-derailing wires for the AIU ) . We had to troubleshoot these things for months The biggest problem and it sounds like you may be running into it is that if you have one bad or flaky motor it will affect everyone of them on the data wire. There were times when all 60 motors hung up Only way to isolate it was to start disconnecting them one at a time. Since there isn't any manual throw this caused major problems on the layout. The throw springs are junk and the version A 2500 used to switch by itself HAd a few head ons as a result. I would never try them again. I don't think you have a length problem on the wire

[gtfan]

It sounds to me like your switch machines may have worked previously more out of luck than anything else. If the method of communication on the data wire is truly RS-232, then the designers chose the wrong medium. RS-232 is the specification for a point-to-point communication system of up to 25 feet maximum. While it can support (and has supported) much longer distances, the key is "point-to-point," which means ONE transmitter and ONE receiver. Driver and receiver chips designed to this specification are not intended to be placed in a circuit with multiple drops and multiple receivers. Instead, the designers should have used RS-422, (http://en.wikipedia.org/wiki/RS-422) which allows for a multi-drop architecture, and uses differential signalling, as opposed to RS-232's single-ended signalling scheme.

That said, it sounds like the best thing you can do to make and keep your current system working, is to ensure that ALL devices on the network have a solid ground reference. This ground reference is necessary because it is what the devices use to determine what is a "one" and what is a "zero" in the data stream.

[G3750]

George, did you try magic lamps???

Hey John, did you take a close look at the wiring diagram? See those bulbs between the terminal strips on the lefthand side?

They were "magic light bulbs" left over from when I tried DCS. Now they simply tell me that juice is flowing to each of the power districts.

George

[G3750]

George
We ot rid of the DZ-2500's because of their problems Went back to the DZ-1000's which are much more reliable. We had 60 DZ-2500's on one data wire driver. We had them wired for TMCC and also DCS operation (DCS using the non-derailing wires for the AIU ) . We had to troubleshoot these things for months The biggest problem and it sounds like you may be running into it is that if you have one bad or flaky motor it will affect everyone of them on the data wire. There were times when all 60 motors hung up Only way to isolate it was to start disconnecting them one at a time. Since there isn't any manual throw this caused major problems on the layout. The throw springs are junk and the version A 2500 used to switch by itself HAd a few head ons as a result. I would never try them again. I don't think you have a length problem on the wire

Ben,

Wow, that's not good news.

I'm not actually sure I can go back to the DZ-1000s. I think that would require a DZ-2000 for each DZ-1000. And I don't think the DZ-2000 is made anymore. Plus, except for these 5 DZ's, the rest work great. I'm working with Dennis Zander to try and isolate the problem. So far the suspects seem to be (in no particular order):

• Data wire length: I measured my data wire driver buss ring and it's 75 feet long. I don't know if that is OK or not. I may be looking into daisy-chaining DZ-2001s or splitting the buss ring into two rings.
• Possible mis-programmed address for the troublesome machine: I don't believe this to be the issue, but I'm going to reprogram it and see what happens.
• 1 faulty machine screwing up the rest: fortunately, we only have 5 to sort out, not 60. I'm not convinced of this either as I checked out all these machines prior to installation (programmed off the layout).

It's a game of attrition. Remove all the variables and what's left is the truth. Have to say Dennis Zander (Z-Stuff) has been responsive and given me some good information.

George