How do you maintain a facility at optimal temperature and
humidity conditions for a textile weaving process, yet maintain
reasonable energy costs? Answer: you put in new high efficiency
lights, install insulated windows and doors, add sky-lights,
a highly efficient centrifugal chiller; and finally, you put
in an intelligent environmental monitoring and control system
like the one at the Interface Fabrics' Weave 2 facility. Working
with the client's environmental consultants, we designed and
implemented a PC-based control and monitoring system.
Because temperature accuracy is important to determine the
performance of HVAC systems, thermistors and a highly accurate
data acquisition/switch unit were required to achieve the
accuracy needed. Normally, the data acquisition/switch unit
must be located close to a PC. In this case, however, communications
with the switch unit was accomplished with a Lantronix Ethernet
to serial "device server". This decision allowed the unit
to be located centrally, minimizing thermistor installation
cost. And we were also able to locate the PC an office environment,
away from the harsher environment of the plant floor. We also
minimized the cost of control wiring to the chiller and air
handler units by using fieldbus I/O.
We used Wonderware FactorySuite for the operator interface
(InTouch), control software (InControl), and remote alarming
and paging software (SCADAlarm). Descartes OmniServer collects
data from the data acquisition/switch unit. We developed the
necessary "protocol" to instruct the unit to acquire and send
the desired environmental information, and soft PLC and OPC
software interface with the fieldbus I/O.
Because environmental consultants and engineers were located
throughout the U.S., remote control and dial-up connectivity
was essential. Using native Windows 2000 dial-up networking
and Netmeeting, the consultants are able to dial-in, view
the system status, and retrieve historical system data.
- Fuzzy control algorithms for chilled water valve, hot
water valve, damper and fan speed control.
- Operator interface and controller software on one highly
- Ethernet fieldbus I/O.
- Oversized buttons for touch-screen operation.
- Trending for problem diagnosis and system performance
- Data storage in a MS Access database.
- Data retrieval with MS Excel.
- Serial-over-Ethernet communications to Agilent 34970A
data acquisition/switch unit..
- Remote control and dial-up networking.
- Wonderware FactorySuite 7.1 (InTouch, InControl & SCADAlarm)
- Descartes OmniServer OPC Server
- Beckhoff TwinCAT I/O & OPC Server
- Microsoft Windows 2000 Server
- Microsoft Access
- Microsoft Excel
- Microsoft Netmeeting
- Lantronix Port Re-director
Client Comments: "This innovative system utilized fuzzy
logic to control difficult temperature loops and gave us the
tight control that our process demanded."
Chatham Project Manager