TNS Asia Pacific Pte Ltd

Overview

The City of Carmel owns and operates a wastewater treatment facility that processes and treats sanitary waste from Carmel, Clay Waste District, Westfield, and Hamilton Western Utilities. The plant runs continuously 24/7 and has the capacity to treat 12 million gallons of wastewater a day. The wastewater facility's innovative strategies and high standards were recognized by the Environmental Protection Agency when it was named the "best municipal plant in its class."

The Wastewater Treatment Plant needed to expand and upgrade their SCADA system. The main objective was to create a reliable network that incorporated existing equipment sites along with additional locations, while ensuring that scalable technology and bandwidth were available for future growth. Fiber was required in many areas because it was easier to deploy for longer distances throughout the facility, and it offered both immunity to EMI and RFI, while eliminating any potential for ground loops.

Industrial ethernet networks must be highly reliable and continue to operate during harsh environmental conditions, accidental network disruptions, and equipment failures. Network downtime can be extremely expensive, such as when pollution control failures lead to the contamination of the water supply. Reliability is usually provided through equipment and communication redundancy, coupled with firmware in the network devices that instructs the network to switch to alternate paths upon specific failures.

Once reliability has been addressed, security becomes a prime concern. These concerns may pertain to user security, as well as unwanted interaction between multiple systems connected to the same network. Regardless of whether the network includes wireless or wired communication, there are numerous levels of security options available in the market. Ranging from simple password protection, to VLANs (which allow a single physical network to be divided into multiple virtual networks), to the use of authentication servers (e.g., RADIUS), the level of security and sophistication is often determined by budget and specific needs.

Solution

The Carmel WWTU needed to network a combination of components within several existing and new buildings at their facility. However, the main objective at the plant centered around the industrial Ethernet network. The plant chose MOXA EDS-728 26-port managed gigabit Ethernet switch for the Control Building because it provided multiple, easily-configured, modularized ports that support multimode fiber for the long distances necessary to cover the entire plant site.

Fiber optic connections provided speed and bandwidth that are orders of magnitude greater than twisted-pair. Equally important, fiber optic connections are not affected by EMI, RFI, lightning strikes, and other disruptions that could compromise both the performance and reliability of industrial networks.

EDS-728 can handle all of the PLC data collection needs required for central control by mixing and matching both copper and fiber ports while leaving room for additional expansion ports in the future. Although gigabit bandwidth was not needed at the time, EDS-728 offered the ability to utilise gigabit ports in the future.

The plant utilised a combination of managed EDS-508A and unmanaged EDS-308 switches for direct connections between PLCs, HMIs, and peripheral devices located in the other 7 buildings. These switches allowed 10/100 Mbps bandwidth, along with a combination of copper (RJ45) and fiber port (SC or ST) connections.

The use of Simple Network Management Protocol (SNMP), allows network managers to configure and monitor network performance remotely. This enabled them to identify potential problems before network capabilities were threatened. Furthermore, all of Moxa's managed switches offered excellent reliability via self-healing network recovery.

Should a fiber is break or a network switch fails, a Moxa Turbo Ring network will self-heal in less than 300 ms. An additional benefit of a ring topology network is the reduced cost of network cabling compared to a Rapid Spanning Tree Protocol (IEEE 802.3D) network.

To increase the security levels of the network, a combination of features available in Moxa's managed switches were activated; Password Protection, Port Locking, MAC ID Filtering, and IP Masking.

Ultimately, the Moxa solution provided the facility with cost effective network redundancy and security between the Control, Biopast, Centrifuge, Return, and North Galley buildings, and the new Ultraviolet Building.

Related Products