Secure Cellular Communication for Water-treatment Applications

In a water-treatment plant, thousands of water quality parameters have to be measured and monitored as raw water goes through the treatment and purification process to produce drinking water that is safe for human consumption. In addition to water treatment and purification, the handling and distribution of water after it is processed is equally important to ensure the quality of drinking water. A common practice to avoid recontamination of water in the distribution system is the retention of residual disinfectants in the treated water. To ensure that the disinfectants do not reach dangerous levels, the quality of water is monitored by equipment installed inside roadside cabinets along the distribution lines. Water meters monitor the quantity of water consumed. Since these equipment cabinets are located in remote areas, a reliable, secure, and fast communication solution, such as an LTE cellular connectivity, which can send the consumption, diagnostic, and status parameters to the control center, is required for effective centralized management of the plant.

Secure and Reliable Transmissions and Other Requirements

To ensure effective centralized management, an efficient water-treatment system requires:

• Secure and reliable long-distance transmission of process parameters
• Internet access for centralized management and control
• Easy troubleshooting to deal with connectivity issues
• Solar-powered battery supply

LTE Gateways

LTE gateways are the key to remotely access sensors and devices that constantly monitor the quality of drinking water. As water-treatment plants usually cover a wide area, using solar-powered batteries as the main power supply is common. Due to their low-power consumption design, LTE gateways can reduce power consumption when a monitoring device is idle, making them suitable for a solar-powered battery operation.

More Features

The OnCell 3120-LTE-1 gateway provides two standby modes to reduce power consumption when the device is idling, enabling it to use solar power. Sleep mode effectively reduces the power consumption to below two watts. The OnCell gateway can be activated from sleep mode with remote SMS control commands or by a preset schedule. Hibernation mode reduces the OnCell gateway's power consumption to under 40 milliwatts. The gateway can be reactivated through a preconfigured schedule or the schedule management function.
OnCell LTE gateways are designed to provide continuous connectivity. The dual-SIM cellular operator backup provides automatic switchover when one of the links goes down. In addition, GuaranLink technology implements a four-tier connection check method that makes continuous connectivity a reality.
Furthermore, OnCell LTE gateways provide secure VPN communication in both server and client roles. Network protocols, such as IPsec, GRE, and OpenVPN, are supported to help you easily establish secure and reliable connections between two networks. The OnCell 3120-LTE-1 also meets the technical security requirements of the IEC-62443 security standard to provide high device-level security.
OnCell gateways also facilitate remote access through OnCell Central Manager (OCM) for efficient system operation. The OCM tool provides centralized private IP connections that enable easy device management, data exchange, and device access control over the Internet.
With the deployment of LTE gateways, water-treatment companies can save travel expenses by remote controlling the devices in real time.

Moxa Solutions

• Moxa's OnCell LTE gateways comply with the technical requirements of the IEC 62443-4-2 cybersecurity standard to prevent unauthorized access of network resources.
• Multiple VPN tunnel options are available for secure and reliable communication over a cellular network.
• The LEDs on the front panel of the OnCell 3120-LTE-1 indicates the current signal stream and cellular mode status.

For more about Moxa’s OnCell product applications, read our application note.