Building Automation System

[gitargr8]

I've been tasked with coming up with a solution to replace an outdated Control Systems International (now called TAC and owned by Schneider Electric) I/Net building automation system with something current.

My background is in industrial automation, so my preference would be to use a CompactLogix 5330ER (capable of 32 Remote I/O nodes and 256 CIP connections) per building with remote Ethernet I/P IO racks, either PointI/O or WAGO 750. The customer also uses BACNet in other locations of their campus, so I would most likely utilize a Prosoft gateway to communicate with T-stats or VAVs. They have a GE iFix SCADA with the IGS driver, so I know I can tie in the Logix platform easily.

Another option would be to just use the WAGO controllers themselves, as it appears that they have a pretty decent library of building automation function blocks and even have a BACNet version. I'm leery of this solution though because CODESYS is not familiar to me, and I don't really know of it's capabilities / shortcomings. Better the devil you know...

My concern with this set up is that the existing CSI system uses discreet outputs that can double as PWM outputs. As far as I know, there isn't really a PWM card out there for AB or WAGO. I'd imagine that a 0-10V analog output signal can be converted to PWM via a signal conditioner, but I'd like to keep the installation as clean as possible.

I'm wondering if there's a better solution out there. Keep in mind, that this would be just a controls replacement, they'd like to leave as much of the existing equipment in place. That's not to say that we couldn't swap out actuators on valves / dampers, however.

Thanks for any input,
~Ryan

 

[harryting]

I looked into replacing a L&S (now Siemens) BCS with PLC a few years back.

The problem is the damper/VAVs. To do this you need VAV Controller that accept open protocal and after all the cost is figured in, I found that I was better off sticking with BCS type controller instead of PLC. The cost comparison wasn't close as BCS are not designed to stand up to industrial use.

Another consideration is that whoever manage the building won't have PLC expertise.

to draw a parallel, it's like control traffic light with PLC when there's specialized traffic light control system out there. You can do it, but cost wise and maintenance consideration it doesn't make sense. The only exception IMO is FDA type production environment.

 

[danw]

When my company was looking a larger facility, a building in a light industrial park, they toured one building which had a PLC for the building controls. It was immediately taken out of consideration.

My company, like many, hires a firm to maintain the building, and they weren't interested in finding someone for that particular brand PLC who knew building automation.

 

[Lancie1]

As far as I know, there isn't really a PWM card out there for AB or WAGO.

No I don't think there is a Pulse-Width Modulation Output module for the CompactLogix PLCs.

...replace an outdated Control Systems International ... I/Net building automation system...

Because the main use is for a building automation system, the only use I could imgagine for a PWM output would be if you have to build your own motor variable speed drives! Most building atomation system use off-the shelf VFDs, so your CompactLogix probably will only need to be able to issue Start/Stop commands to those drives.

A better question is: Does your Building Automation system have to be able to interface directly with the HVAC equipment speed controllers over a comm network such as Devicenet, Modbus, or Ethernet? For example the CompactLogix can communicate directly with a Allen Bradley Powerflex VFD. Does your new building automation system have to communicate directly with its VFDs? If so, what brand VFDS, and can they be made to use the CompactLogix communications protocols?

I agree with the others. If you need a building automation controller, then buy a special-purpose building automation controller, not a general-purpose PLC (which will not be compatible with much of the building HVAC system).

 

[gitargr8]

Thanks everyone for the feedback. As far as VFDs, it looks to me like all the motors are currently controlled via soft starts, which take a discreet signal. I'll have to verify that this is the case in the field, but I don't believe the control system is talking to the drives over a fieldbus.

Any recommendations for BCS controllers? Ideally it would be cheap, modular, and able to talk OPC to iFix and BACNet to field devices.

 

[harryting]

Funny, I googled PLC and open standard VAV and found my OWN posting in HVAC forums many years before.

Memory is fuzzy but I think I looked into Alerton which uses on BACnet. Another bunch of people uses IonTalk. At the time I also looked into just using the HMI which was RSView via OPC to the Siemens system but found out there's many limitaion on the OPC server that Siemens supplies (it was a weird protocol).

With BacNet you should have no problem find a better functioning OPC server from the major OPC suppliers. So, yes, I would go that route. You can keep all your VAV plus getting a few area controller from Alerton and view it via existing iFix installs. If you use IGS server, it's basically KEPware and I'm sure you can just order the BACNet portion from GE.

 

[gitargr8]

Thanks, I will check them out. They have already upgraded one of the buildings to Logix and BACNet, so I shouldn't have any trouble configuring another BACNet channel in IGS.

 

[JERA]

Any recommendations for BCS controllers? Ideally it would be cheap, modular, and able to talk OPC to iFix and BACNet to field devices.

Take a look an ABB AC500
I have used this for a building automation system

 

[JHarbin]

I've been tasked with coming up with a solution to replace an outdated Control Systems International (now called TAC and owned by Schneider Electric) I/Net building automation system with something current.

My background is in industrial automation, so my preference would be to use a CompactLogix 5330ER (capable of 32 Remote I/O nodes and 256 CIP connections) per building with remote Ethernet I/P IO racks, either PointI/O or WAGO 750. The customer also uses BACNet in other locations of their campus, so I would most likely utilize a Prosoft gateway to communicate with T-stats or VAVs. They have a GE iFix SCADA with the IGS driver, so I know I can tie in the Logix platform easily.

Another option would be to just use the WAGO controllers themselves, as it appears that they have a pretty decent library of building automation function blocks and even have a BACNet version. I'm leery of this solution though because CODESYS is not familiar to me, and I don't really know of it's capabilities / shortcomings. Better the devil you know...

My concern with this set up is that the existing CSI system uses discreet outputs that can double as PWM outputs. As far as I know, there isn't really a PWM card out there for AB or WAGO. I'd imagine that a 0-10V analog output signal can be converted to PWM via a signal conditioner, but I'd like to keep the installation as clean as possible.

I'm wondering if there's a better solution out there. Keep in mind, that this would be just a controls replacement, they'd like to leave as much of the existing equipment in place. That's not to say that we couldn't swap out actuators on valves / dampers, however.

Thanks for any input,
~Ryan

We have used Quickservers (Google it) for LON on one side and Modbus TCP on the other. We have used the Redlion DSPLE for BACNET to Modbus TCP.