View Full Version : TAC to Alerton Backnet
03-20-2007, 01:27 PM
i have two sites , one with an Alerton System, and the other one is TAC system, the alerton system uses backnet protocol, and the TAC system uses LON protocol, how can i connect both systems, i read that using Xenta 913 gateway it is possible to connect such systems, but my question is: is it possible for Envision workstation to connect to TAC devices through there gateway, or only TAC vista will be able to connect to Alerton field devices ??
03-20-2007, 08:42 PM
From what I was told it is only a one way street: from BACnet to LON (meaning you can bring BACnet points into Vista) but controllability is a question I don't have the answer to.
You might want to look at this from Loytec, never used one but it might be your answer.
03-21-2007, 06:23 PM
Just get yorself a Fieldserver bridge.
If you need config, go to Mac over at Sierra Fothills integration
It can be problem with Xentas as TAC Xentas and Vista system are normally (?) built not to use SNVT-s but own explicit messages on LON. Loytec or Fieldserver can help after someone (?) had modified Xentas to use/support SNVT-s.
03-22-2007, 09:46 AM
All their ASC are based on SNVT, but the freely controllable controllers (Xenta) generally use Vista points and only have 15 nvi and 15 nvi that you can map Vista points to in the 300 series and alot more in the 400 series (can't remember the count off the top of my head).
Unless the originally t.a.c. contractor programmed the system to be as fully open as possible (with the above limitations) you won't see any points in the freely programmable controller.
I think the 511 can be a gateway to map Vista points to SNVTs, but this has to be done on the Vista side through Menta if I remember correctly. Remember that if you want to control a point in a freely programmable controller it will take up 2 ncis (one to tell the controller to be externally controlled and one to set the value in Menta) and additional programming will be required on the Menta side.
This knowledge is all 12-18 months old, things might have changed in that time and if any of the other members have updated knowledge please fell free to post the correct updated information.
The t.a.c. gateway is for the Vista front end to have the ability to see and control BACnet points, not for BACnet OWS or devices to control t.a.c. devices.
03-22-2007, 10:47 PM
Kphreak - here's an update.
The asc's do use SNVT's but it is up to the programmer on the 280/300/400 series to use either SNVTs or TACNV's (tac network variables). On the 280/300 series the limit is 15 nvi's and 30 nvo's. Again one is taken up in the address table and service pin setup and the other is taken for TANV's so on the nvi's there is only 13 available for SNVT's. On the 400 series it is 125 nvi's and 125 nvo's.
On the 511 you do not need Menta at all. You need xbuilder to program the 511 and that is where you can setup SNVTs in/out of the 511.
03-23-2007, 01:23 AM
Thanks for the update. It's been awhile since we dealt with Vista. Started with the new company on Monday and have been at t.a.c. Andover school all week. I must say I am really impressed. We did 2 projects at my last company and they went well (one involving 90+ heat pumps on 4 wireless networks), but I hadn't been to training.
Since I will be commissioning Andover for the next 2 years the new company sent me to training my first week.:D
Great system (I'm training on the old proprietary system) and I am really impressed. The BACnet is actually a dumbed down version of it, even though it is open it takes a lot more work to configure it to be compatible with other systems.
One of the funny/interesting things I learned was that their proprietary system use an Echelon chip and LON on their IO net. So much for LON being "open" to any LNS based database, as only Continuum works with their bastardized LON. Seems they had planned to bring out a whole LON line before they decided to jump on the BACnet bandwagon.
So far I have been impressed and actually like their proprietary line a lot.
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