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Crestron Systems - Programming? - Page 4

post #91 of 111
The shield is electrostatic, like a Faraday cage.

The twisted pair ensures that induced electromagnetic interference couples to both conductors equally, for effective cancellation at the differential receiver.

Differential signalling doesn't require a ground reference.
A telephone line has no shield or ground reference for the AC (audio) signal.
post #92 of 111
And the Faraday cage is used to reduce EMI.

Thanks for the help, Sam.
post #93 of 111
Quote:
And the Faraday cage is used to reduce EMI.

No, electrostatic interference.
post #94 of 111
Found a good reference that explains electrostatic and EMI. Chapters 2 and 3, from a recording studio design site.

http://members.ozemail.com.au/~tabbler/GndRule/GndM02.html

The foil shield is to reduce electrostatic interference, and the pair twists are to reduce EMI.

Now I think I've got it, with the explanation.
post #95 of 111
Sounds like youze guys are still up in the air about what to use for your own cresnet, so I'll tell you of my experimentation.
My whole house was wired with cat5e before I decided to get involved in a Crestron system. I have tried this both ways and have had no problems either way. I have used a twisted pair for each conductor (all four) and I have used a twisted pair for +, one pair for - and one pair for signal, leaving one pair for a spare. My system has been in for years now with no problems.

"So, then what's the purpose of the shield, for the Cresnet control pair?"

Just because the DC in the cresnet doesn't cause EMI, doesn't mean you didn't pull the wire in close to a AC motor feed or something.
That said, I have some of that cat5e I spoke of earlier pulled through the same chase as a 50 amp feed for my pilot arc plasma cutter and AC/DC TIG welder. My wife has not complained of any TP problems associated with that pull when I'm out working in my shop.
post #96 of 111
I bought a TP for learning programming. I honestly don't plan on installing it, but who knows what I'll eventually end up doing.

On the test bench, I'll use 18/2 x 2. For the 2 feet, twists (and probably shield) won't make a difference.

My only obstacle is free time.
post #97 of 111
Quote:
Just because the DC in the cresnet doesn't cause EMI, doesn't mean you didn't pull the wire in close to a AC motor feed or something.

Google "differential signalling" for the answer , it's like you're not even reading this thread.
post #98 of 111
Quote:
Originally Posted by SAM64 View Post

Google "differential signalling" for the answer , it's like you're not even reading this thread.
Would be also good to google common mode rejection ratio (CMRR) while you are at it to realize balanced interconnect doesn't mean you are immune to noise smile.gif. There is a reason shielded twisted pair cable also exists.
post #99 of 111
He's goading you, Ace.

Thank you, Amir. I've spent enough time reading about the esoterics of RS485 design, common mode noise rejection, foil shielding, and electrostatic interference. It's interesting, but not too relevant for practical purposes.
post #100 of 111
Quote:
There is a reason shielded twisted pair cable also exists.

Tell us about it then wink.gif
post #101 of 111
Quote:
Originally Posted by SAM64 View Post

Tell us about it then wink.gif
I am not going to do that. The guys are trying to learn about programming Crestron. It has nothing to do with arguing about shield vs not when they are just building a test fixture. Let them be please.
post #102 of 111
It's true that I have not kept up with this thread from start to now but if you read all of page one including the title of this thread you will see that this is a learning programming thread not how wire design works on paper. I have a friend who claimes to be able to tell the difference in sound with his speaker wires elevated off the floor. One of these days I'm going to challange that with blind side test, a switch and a roll of 12-2 romex.

Now if we are still talking about hooking up a test system on the bench, you could straighten out four coat hangers for your Cresnet and it will work just fine as long as they are not touching.wink.gif
post #103 of 111
Hi all,

Firstly thanks for sharing your experience and advice.

I also am interested in a career change and am wanting to get into the home automation\control programming line.

I have done a few systems successfully over the past 5 months with Axium and Elan products.

I realize that Crestron is the industry leader in this regard and would like to get up to speed. I am aware of the steps to begin.

1. Subscribe to the Crestron yahoo group.
2. Sign up for training.
3. View the intro videos on the Crestron site.
4. Download the programming software.
5. Look through the demo programs.
6. Skip anything that says System Builder/SB.
7. Get your hands on an MC3 controller.
8. Play with it.
9. Attend training.

Before i dive head first and get this ball rolling i would like some advise please. We have a few Crestron products @ the shop and was wondering if they would be a good place to start.

http://www.crestron.com/resources/product_and_programming_resources/catalogs_and_brochures/online_catalog/default.asp?jump=1&model=st-1700c

http://www.crestron.com/resources/product_and_programming_resources/catalogs_and_brochures/online_catalog/default.asp?jump=1&model=cnx-pad8a

http://www.crestron.com/resources/product_and_programming_resources/catalogs_and_brochures/online_catalog/default.asp?jump=1&model=cnmsx-pro

Any advice in this regard would be greatly appreciated.
post #104 of 111
Most importantly, you'll need access to Crestron software. Crestron equipment cannot be programmed without the sw.
post #105 of 111
Quote:
Originally Posted by AceInfinity View Post

Not really, the touchpanel can be powered via Cresnet because 24 and G are power, Y and Z are both data. I'm not even using any other ports, the only connection I have to my TPS-4000(L) is through Cresnet by phoenix connector. I don't have the TPS-IMPC or TPS-IMW, it's just my MC2E processor and the TPS-4000L. Connected by Cresnet. No interface module is required really (from what I know anyways).
Typically because 24 and G are power, red being hot would go to 24 and black would go to G. You'll notice with Cresnet wire that the Red and Black wires are a bit thicker than the white and blue. That's the reasoning behind this smile.gif
But then, from there for my system that i've been working on, i've also got IR emitters on the Serial/IR output which is controlled by touchpanel actions.
Cresnet on the TPS-4000L back to the MC2E:
NZr8e.jpg


What's with the terminal blocks for composite and Svideo? We have standard industry connectors for these - Svideo standard 4pin miniDIN and RCA or BNC for composite.
post #106 of 111
Quote:
Originally Posted by Glimmie View Post

What's with the terminal blocks for composite and Svideo? We have standard industry connectors for these - Svideo standard 4pin miniDIN and RCA or BNC for composite.

Y/C (S) was often run as two-wire for the best quality over distance. On larger equipment it was common to have two BNCs for Y and C (S-Video) plus a BNC for CVBS (Composite). I imagine that they did this to save space. Plus it's a lot easier to terminate using screw terminals than field-terminating a bunch of BNCs.
post #107 of 111
Quote:
Y/C (S) was often run as two-wire for the best quality over distance.

If it was for 'best quality' they would have used BNC's and 75 Ohm coax.
post #108 of 111
Quote:
Originally Posted by SAM64 View Post

If it was for 'best quality' they would have used BNC's and 75 Ohm coax.

Agreed, that's my point.
post #109 of 111
Thread Starter 
Bringing this thread back to life to ask the knowledgeable members that contributed in this thread when I first started it. I have a question about relay triggering, as simple as it should be...

Right now, I've figured out a lot of things for my system, on a basic level. I've figured out how to poll the projector for information and update the UI on my touchpanel to give some meaningful user feedback. I'm curious about perhaps a couple things now, hints or anything at all is appreciated.

For my screen control, it's closed contact, I've got the screen going up and down by relay outputs, projector control via serial, and I've got my wallplate control for the screen paired with the screen motor as well. The wallplate works with Up, Down, and Stop. My touchpanel can only control up or down, and I can't tell it to stop, regardless about my relay timings, because in order to physically stop the screen I would need to trigger 2 output relays at once. I've tried a few guesses within Simple Windows to try and do this, but it appears the second relay will only trigger after the first one goes back into position; they don't open/close at the same time.

Is this a limitation of the MC2e controller I am using, or am I just not doing this right within programming?

@Glimmie - I didn't design the control interface for the touchpanel I have, and in fact, it's actually a discontinued product... I would agree though. I got it for free, the only downside is it's outdated style and low resolution (~640x480) for my current application. smile.gif I'd love to get into some UI where I can actually use Core3UI for my own home system though eventually.

I'm playing around with lots of equipment as it is. I've automated some DMX-512 based lighting just recently for my pool system.
Edited by AceInfinity - 3/14/14 at 6:23am
post #110 of 111
The relays should operate independently. Are they being triggered in programming via the outputs of a Toggle or Set/Reset Latch (only one output high at a time?)


You should be able to take the signal from a button press and pass it through a buffer to the trigger signal for both of the relays.





If the relay triggers are attached to the output of a toggle, s/r latch, etc you'll need to buffer those outputs as well to avoid compiler warnings.
post #111 of 111
Thread Starter 
Quote:
Originally Posted by weddellkw View Post

The relays should operate independently. Are they being triggered in programming via the outputs of a Toggle or Set/Reset Latch (only one output high at a time?)


You should be able to take the signal from a button press and pass it through a buffer to the trigger signal for both of the relays.





If the relay triggers are attached to the output of a toggle, s/r latch, etc you'll need to buffer those outputs as well to avoid compiler warnings.

Hmm, I'll go and try the advice I've been given and see how she goes, thanks for the guidance. smile.gif

EDIT: It worked. I got it working putting them through a buffer. Great!
Edited by AceInfinity - 3/13/14 at 8:00pm
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