DMX End Address & Passing all 512 channels

[soakes94]

Is it possible to set a DMX end address? So that maybe I have a Ren48LSD and I'm only using channels 1-32. Just so I'm then not sitting with 16 empty channels taking up room and making things complicated when it comes to sequencing. Also is it possible to have the firmware pass on all 512 channels so it doesnt matter what order I set my display up in each light still reacts to its pre-programmed channel if that makes sense.

My aim at the end of this is to have lots of 8 channel DC circuit boards that use a pic16f688 (Same as the ren48lsd, if I remembered the pic name correctly). I want to be to set each citcuit board to only react to a set number of channels, so while the PIC can output 8 channels I would only want it to lets say output 5 for a specific light fitting or in other cases maybe 6 channels. I also want it to pass on all channels so each light will be the same channel every year.

How easy would it be to change the firmware? In a summary the change would be adding an end address and passing all 512 DMX channels on.

Thanks
Steve

[mschell]

Anything is possible with firmware changes.

Back when I started hanging out here on DIYC, I was asking for the same thing, mostly because I was used to the DMX world, where all the channels get passed to the next controller. In the Renard world, with the exception of doing the wireless thing, the expectation is that each controller will take all the channels that it uses and pass on the rest. There were a few times when a board designer would give you a "pass-thru" port to enable all the channels to pass thru, but some of them stuck and some of them didn't.

I think the new Ren4Flood or some other board mentioned here recently does have a pass-thru.

The issue is that with most of the current Ren hardware design, the signal passes from PIC to PIC and is then sent on to the next controller from the last PIC. It's just easier to strip off the bits that it's using and not pass them on. That also makes it easier for the firmware settings on each PIC, since all it has to do is listen to the first 8 signal levels and so can be set at address 1 each time.

Since I'm using DMX for all my DIY boards, I just chose to use some DMX splitters before the signal for that DMX universe goes to any controllers. That way, my CoroFlake gets it's channels, and the Ren48LSDs get all the channels it needs. If I wasn't using the last 16 channels of the Ren48LSD, I could just set the starting address of another fixture to address 33 and it would work.

Non-isolated DMX/RS-485 splitters are fairly inexpensive and can fix inside a TA-200 box or just stay inside in the garage.

[P. Short]

Like mschell says, anything can be done in firmware. Well, anything within the capabilities of the processor involved. You, or anyone else, is welcome to create new versions of the firmware. The only request that I have is that you pay a lot of attention to documentation and avoiding confusion wrt the existing firmware.

As to why things are the way they are, remember that the DMX firmware for Renard was created after there were already a significant number of Ren64 controllers already built up, as well as the 16-channel Xmus boards and 24-channel boards from Frank Kostyun. The firmware was intended as a retro-fit onto those existing boards, as I figured that people starting out with DMX from the very beginning would chose some other board design. My basic (and pretty much only) goal was to make a Ren64 board to appear as a single 64-channel DMX controller, generally requiring an up-front splitter. The 'pass-through' capabilities of that board was an unintentional result of making a board with eight micros appear as a single device.

So, I second Mark's suggestion: use DMX splitters as the 'pass-through' mechanism, not the RS485 output connector on the Renard controllers.

[soakes94]

If I take this design http://www.diylightanimation.com/wiki/index.php?title=Manual_Splitter

Would I take the feed for the circuit board from the input and then make the output, Output 1? Or would I split it and take the feed for the circuit board from output1 and the output from output2? If that makes sense?

Thanks

[P. Short]

It appears that the input and output1 connectors are wired together. If you were to use that device, I'd run the input cable to the input connector of that device, use either output1 or output2 to go to the Renard, and outputs 2 (if available) and 3 to go to downstream devices.

If you are willing to rework the Renard board, you could cut the trace going from the last PIC to the input of the RS485 transmitter and jumper the output of the RS485 receiver to the input of the RS485 receiver. This disadvantage of doing this is that your board is no longer 'original', and the downstream devices would quite working if your Renard controller loses power.

[soakes94]

Im designing my own PCB based on a ren48lsd instead of 48 channels it will have 8 but it will operate the same so I am happy to make a modification.

To make sure I get this right I wouldnt connect pin6 of the pic to anything.

And I would connect Pin1 of the recieiving ST485 (Pic-Rx) to Pin4 (Pic-Tx) on the transmitting ST485?

And I would also connect Pin1 of the recieving ST485 (Pic-Rx) to pin 5(Pic-Rx) on the Pic16f688?

If thats correct I will finish my schematic and upload here and maybe someone could look over it?

Thanks

[soakes94]

I made a rough schematic, so applogies if its not very tidy. Its the first one I've ever made haha. Ive attached it along with the schematic for the ren48lsd which I based it on.

Will this work? Or does it need some adjusting?

Cheers

[P. Short]

Yes, although my inclination would be to add jumpers so that pin 4 of the transmitting ST485 could be connected to either pin 1 of the receiving ST485 or pin 6 of the PIC. If you are going for DMX only, I'd use the standard pins for the DMX RJ45 connector (see the sticky thread in the DMX forum). And if you are trying to use the Renard pinout, pins 4 and 5 are reversed (what you show is the LOR pinout, I think).

[soakes94]

If you hadnt said that I would have looked over that completely and then would be so annoyed when I had to build cables and things to sort it so thank you! I will get those changes made.

Apart from that how does the circuit look? I noticed I left out some .1uF caps over the Pic and IC's. I also left out the zener's by accident so I will update it and reupload it :)

Steve

[soakes94]

Ive attached an updated schematic, I'm a bit confused around the zener diodes and 27K resistor as they connect to pin 2 of the output but my DMX out is also connected to that? Is that right?

Also I notice that alot of the RJ45 pins are connected together but dont seem to be connected to anything else, do they need to be linked?

Steve

[P. Short]

The zener diodes are present on the Renard design only to allow the board to be directly connected to the RS232 output of the serial port. They are not needed for a pure DMX design.

[soakes94]

That makes me life even easier, if I take them out, from what you can see, should this design work? I'm going to try and build something on a bread board later.

Cheers Steve

[P. Short]

Also, some of the RJ45 input pins are connected to the RJ45 output pins in order to allow power for the controller and the ZC signals to be passed from the first controller down to the other controllers. This is not needed for your design. This pass-through aspect is a Renard-only feature that is only used by a few people, if at all.

[soakes94]

Built it on a breadboard and it works! I still need to connect up another board to check that the DMX pass works but so far its looking good :)