Trend Controls 3XTEND

**PBW28** · 03-30-2011, 02:49 AM

Hi There,

Hoping some of the Trend experts might be able to help out !!

Is there a recommended number of LON devices to hang off a 3XTEND? Like anything I imagine there is a maximum number of devices however there is also an OPTIMUM number of devices to ensure fast response etc.

I am looking at a job that has 300 IQL-VAV devices on one 3XTEND, divided up by routers (IQL Router) could this be percieved as excessive??? In attempting to solve some issues we are considering adding some 3XTENDS so it would be nice to know what the optimum number of VAV's for good response time would be.

Any comments welcome.
Cheers

**orion242** · 03-30-2011, 09:15 AM

I personally would not put that many on devices on a single extend. Mainly because if it fails I just lost the whole dang building. Also if your not careful with the amount of traffic passing through it, it will likely lock up. This would happen really often on the old firmware, which I would make sure its current on this one for sure. If I designed this system I would have broken the lon network over at least two extends.

In the past I have had little issue with ~150 devices to the extend pending my comms over the network are in check.

**PBW28** · 03-31-2011, 02:29 AM

Hi Orion,

Thanks for the advice there are around 2,500 IQL's in the building so when they lose one they lose about 6-8 floors. However even this is a bit dodgy.

Is it possible to alter the points exposed to the LON network in the IQL-VAV?
Our advice so far is that the device is not programmable....or shall we cannot be altered.

The second issue was that the best update times (say to poulate a screen of VAV data) is about 40-50 seconds for around 30 values all from the same device would you expect this sort of population speed normally?

The 3XTENDS are being polled by IQ3 controllers used for logging and they are logging around 5-7 values (VAV type dependant) every 15 minutes which would cause a fair amount of traffic.

The worst part about the way the system is configured is that all data from the buildings comes through a "master" 3 XTEND for each building, if this falls over ALL access to the building is lost.

Anyways I think spreading the love by adding 3XTENDS may be a worthwhile excercise.

Thanks for your assistance

PBW

**orion242** · 03-31-2011, 07:26 AM

>Our advice so far is that the device is not programmable....or shall we cannot be altered.

That's not totally true. They can be programmed, however you need to send in the files and have them compiled, then you can do a firmware download to install them. Programming them is less than straight forward.

>is about 40-50 seconds for around 30 values all from the same device would you expect this sort of population speed normally?

Nope, that seems excessive. It’s likely due to the traffic.

>IQ3 controllers used for logging and they are logging around 5-7 values (VAV type dependant) every 15 minutes

Yikes, hope that is staggered out and not hitting all at once on the quarter of the hour. If it's not, that is going to be nothing but problems.

**PBW28** · 03-31-2011, 08:02 AM

Thanks for the feeback Orion.

This helps a lot. I was sure the Trend systems I had seen in the past were significantly more responsive.

The reprogram ability sounds like a possibility our client would be happy to think about.

Its quite a significant sized system and the local agent is doing stuff all to assist....not only are there lumps every piece of carpet but the cupboards are bursting at the seams with skeletons!!

I appreciate the heads up!

Cheers
Brendan.

**xarralu** · 04-20-2011, 10:12 PM

Originally Posted by orion242

>Our advice so far is that the device is not programmable....or shall we cannot be altered.

That's not totally true. They can be programmed, however you need to send in the files and have them compiled, then you can do a firmware download to install them. Programming them is less than straight forward.

So Orion, with Trend you are not able to do your own program changes?

**orion242** · 04-21-2011, 07:43 AM

This only applies to the lon controllers, which in all fairness are sold as a non-programmable ASCs. All other controllers, including the new BACnet line, are fully programmable without any extra bs.

**xarralu** · 04-23-2011, 09:39 AM

Originally Posted by orion242

This only applies to the lon controllers, which in all fairness are sold as a non-programmable ASCs. All other controllers, including the new BACnet line, are fully programmable without any extra bs.

Thanks for the reply thus far Orion. I got another question for you. What type of
Programing language do they use? Is graphical block style or line coding? TIA