JCI/Metasys System N2

[noskilltech]

All the programming in the NAE is viewed through internet exploded. I'm not exactly familiar with the Z series with the lon, but I would assume that all they are doing is reading data and commanding some setpoints. I would highly doubt with all the OEM equipment I've dealt with in the past that you will be able to control the VFD output once you do get into the NAE.

I know in the past what I've done on your type of situation is use my own DP sensor and sent my own signal to the RTU controller. Your factory transducers will be your run of the mill "economically priced" transducer that we all can buy from Kele, ACI, etc. They should have a 4-20ma, 0-5vdc or 0-10vdc signal going back to the carrier control board. What I would do is take the factory transducer out of the unit, install it in your common duct work and run that to your own programmable controller. Then take 3 seperate AO's out of your controller back to the input on the RTU controller. You can program your controller or three controllers with logic so that all three units are getting the same exact static signal all the time. You'll have less labor doing that than beating your head against the wall trying to get the factory controller to do it.

[apprentice3]

All the programming in the NAE is viewed through internet exploded. I'm not exactly familiar with the Z series with the lon, but I would assume that all they are doing is reading data and commanding some setpoints. I would highly doubt with all the OEM equipment I've dealt with in the past that you will be able to control the VFD output once you do get into the NAE.

I know in the past what I've done on your type of situation is use my own DP sensor and sent my own signal to the RTU controller. Your factory transducers will be your run of the mill "economically priced" transducer that we all can buy from Kele, ACI, etc. They should have a 4-20ma, 0-5vdc or 0-10vdc signal going back to the carrier control board. What I would do is take the factory transducer out of the unit, install it in your common duct work and run that to your own programmable controller. Then take 3 seperate AO's out of your controller back to the input on the RTU controller. You can program your controller or three controllers with logic so that all three units are getting the same exact static signal all the time. You'll have less labor doing that than beating your head against the wall trying to get the factory controller to do it.

Yeah I thought about doing something like that, but I just wanted to make sure that nothing was inside of the NAE that was doing this. There current JCI tech had told him that this sequence exists, but I cannot see anyway that they are currently even doing this. Maybe I will set up a Carrier controller to take control of some of these sequences if all the NAE is doing is monitoring and writing setpoints. If I wanted to log into the NAE through internet explorer would I just have to have the IP address of the controller, and the metasys user name and password?

Thanks!

[berg2666]

Go to Johnson Controls website In the search bar at the top right hand corner type in Product literature. In that type in or look for NAE Commisioning and or technical bulletin. This will go into more detail. Up front you need internet explorer. Also there is an IP address of the NAE.... You open IE(not firefox) Type in http://IP address/metasys or http://hostname/metasys The building staff can provide this. Also they can provide a user name and password. If you find the NAE commisioning guide you will find the factory password in it also. Again you will find lots of information in the product literature and with more information you can get further help on here. The first time you get on there go to the "help" tab at the top of the browser and find the metasys revision. It will be a number like 1.1 all the way up to 5.2.. It will prove helpful in the future. And look on the computer you are using onsite and see if the is a program called SCT, system configuration tool, It is used to do offline program and archiving of the NAE. And of you can get a back up of the NAE other here can help you further.

[alcomech]

Are you sure that the 3 RTU's are feeding the same supply air duct. I guess this can be done but this is not that common. What kind of building is it. Is it office space, individual tenants, or open areas. How many floor does this building have?
Have you verified actual duct static pressure with a magnehelic gauge, down stream of the duct work and also at the static pressure transducers. And if so what static pressure are you trying to maintain.

Have you tried running the units in test mode or stand alone through the use of it own schedule. How about checking the the set up of the VFD whether it is set up as unit control or external control. Have you checked the ramp up time for the three VFD's.

[apprentice3]

I will check into that information. Thanks a lot. As far as the SCT software goes the customer doesn't have that. Where can I get that at? Do I need that software to view all of the internal logic? Or can everything still be done in Internet explorer?

[apprentice3]

Yes all 3 RTUs do feed into a common duct. Trust me I know that it is not typical. This is a office building with VAVs on the RTUs

[apprentice3]

[QUOTE=alcomech;14046341]Are you sure that the 3 RTU's are feeding the same supply air duct. I guess this can be done but this is not that common. What kind of building is it. Is it office space, individual tenants, or open areas. How many floor does this building have?
Have you verified actual duct static pressure with a magnehelic gauge, down stream of the duct work and also at the static pressure transducers. And if so what static pressure are you trying to maintain.

The building has 6 floors. I have verified the actual duct pressure with a magnahelic. The static pressure they are trying to maintain is 1.5" w.c. Typically on these type of systems I have noticed that all of the units should reference the same static pressure pick up. At this building they are referencing the internal sensors to the unit. 2 of them a reading pretty close to the actual pressure in the duct. One of them is about 1.2 " w.c. low. I have already made recommendations to fix this problem.

The ramp up time on the three VFDs is identical. The VFD is also currently being controlled internal to the unit as well.

Thanks!

[alcomech]

Sounds like you are on to something here. Have you checked the maximum static pressure set point which will put the unit in alarm.
And if so what is the set point.

Also were is the static pressure transducer/ or velocity pick up located at. It should be located 2/3 down stream of the unit so that it will maintain true static to the last VAV's

[alcomech]

I wonder if your actual static pressure set point is set too low at the Carrier control panel. At 1.5' W.C. there may not be enough pressure in the duct to the last and final 1st floor. Check the static at you last VAV to verify this. In addition you can get the required velocity set point by using the equal friction method

In addition you will want to balance out a couple of the VMA VAV controllers so that you know what they are doing.
You will need to use the VMA balancing tool through the use of HVAC Pro software or with the use of the VBT VAV balancing tool. If you have gotten into the front end it is possible to verify air flow and static there. But each VMA should have been balanced at start up along with its actual CFM out put and Pick-up gain/coefficient value

Equal Friction Method:
Area (Sq Ft.) = CFM divided by velocity FPM
where as: area = 15000 CFM divided by 1500 FPM = 10 Sq
10 Sq. Ft x 144 (Sq. Inches per Sq. Ft)/24" = 60"
Therefore, select 60"x24" supply duct


5400 CFM ÷ 1700 FPM velocity = 3.18 Sq Ft. Duct Area


Aspect Ratio = 48/12= 4
Aspect Ratio 4 = 144%
Round duct = 66%
Differance = 78%

Velocity FPM = airflow CFM/ area in Ft Squared

Velocity x Area = CFM

To Figure CFM by known Sq Ft area and Static Pressure.

External Static Pressure Method:
This called total external static Pressure.
A differential manamoter is used to measure the air pressure at the inlet and outlet of the blower assembly. This pressure is the same pressure a balloon has pushing against its internal walls. Air Blowers have the same type of pressure at the inlets and outlets. The measured air is compared to design charts provided by the equipment manufacture to determine how much air volume is flowing in cubic feet per minute. (CFM).

[apprentice3]

Sounds like you are on to something here. Have you checked the maximum static pressure set point which will put the unit in alarm.
And if so what is the set point.

Also were is the static pressure transducer/ or velocity pick up located at. It should be located 2/3 down stream of the unit so that it will maintain true static to the last VAV's

The maximum static pressure setpoint that will put the unit into alarm is 3" w.c.

The location of the static pressure pick ups are definitely problems. It is right off the discharge of each unit. So basically each unit has its own pick up. I know that this is definitely a problem. I told the customer yesterday about installing one pick up 2/3 down the duct and referencing that one value back up to all 3 units.

[apprentice3]

I wonder if your actual static pressure set point is set too low at the Carrier control panel. At 1.5' W.C. there may not be enough pressure in the duct to the last and final 1st floor. Check the static at you last VAV to verify this. In addition you can get the required velocity set point by using the equal friction method

In addition you will want to balance out a couple of the VMA VAV controllers so that you know what they are doing.
You will need to use the VMA balancing tool through the use of HVAC Pro software or with the use of the VBT VAV balancing tool. If you have gotten into the front end it is possible to verify air flow and static there. But each VMA should have been balanced at start up along with its actual CFM out put and Pick-up gain/coefficient value

Equal Friction Method:
Area (Sq Ft.) = CFM divided by velocity FPM
where as: area = 15000 CFM divided by 1500 FPM = 10 Sq
10 Sq. Ft x 144 (Sq. Inches per Sq. Ft)/24" = 60"
Therefore, select 60"x24" supply duct


5400 CFM ÷ 1700 FPM velocity = 3.18 Sq Ft. Duct Area


Aspect Ratio = 48/12= 4
Aspect Ratio 4 = 144%
Round duct = 66%
Differance = 78%

Velocity FPM = airflow CFM/ area in Ft Squared

Velocity x Area = CFM

To Figure CFM by known Sq Ft area and Static Pressure.

External Static Pressure Method:
This called total external static Pressure.
A differential manamoter is used to measure the air pressure at the inlet and outlet of the blower assembly. This pressure is the same pressure a balloon has pushing against its internal walls. Air Blowers have the same type of pressure at the inlets and outlets. The measured air is compared to design charts provided by the equipment manufacture to determine how much air volume is flowing in cubic feet per minute. (CFM).

Wow this is a lot of information. Thanks for all of you help. Next week I will get into the VAVs and review some of there setpoints. I was also looking into this SCT software on JCIs website. Is that software absolutely necessary to view the logic? Would JCI typically leave that on the end users main computer?

[TommyC11]

I have more of a service controls background. I have worked on a lot of different systems out there. I have only done some mild programming. I usually catch on pretty quick once I get going though. So I think some sort of training would be good. I have thought about upgrading this system to a Tridium system. My company hasn't got into Tridium yet, but I have been on them for a few years now letting them know how big of a player Tridium is in the controls market. They are strongly considering sending a few of there programmers, and myself to AX training. I agree this would definitely be the best solution to the problem. On this job there is some pretty custom logic that the JCI system doesn't contain that I would have to put into the Tridium. Do they have a lot of different programming blocks for most applications?

apprentice3... if you want some assistance, please send me a private message. I am in the Columbus, OH area and can help you with whatever you need... figuring out what you have, where you need to go, accessing your current site, etc...



Tommy C...

[MatrixTransform]

http://IP address/sct or http://hostname/sct
u:metasyssysagent
p:XMG3-Rel.1
http://cgproducts.johnsoncontrols.co...DF/1201519.PDF

and if he stuffs it up then somebody from JCI will get a call
...and if he doesnt then ... well, thats the way it should be.