Ethernet communication is rapidly gaining popularity in industrial applications because it enables the real-time exchange of information between processing equipment and companies Ethernet-based management systems.
One temperature controller designed for such automation solutions is Watlows EZ-ZONE PM controller. EZ-ZONE PM provides a wide range of serial communication choices including EtherNet/IP, Modbus RTU and Modbus TCP. These protocols offer the ability to easily and inexpensively connect to a PC, programmable logic controller (PLC) or human machine interface (HMI) to remotely configure, manage and monitor the systems performance. With the EZ-ZONE PM controller, the engineer has the option to configure a panel mount controller as a high amperage power controller output with a high-performance PID controller, an over/under limit controller or these functions can be combined into an integrated controller.
Watlow's SERIES PD process controller utilizes embedded Ethernet technology to provide a convenient, economical means for setting up and viewing key process variables. The SERIES PD controller is suited for a broad range of temperature and process control applications where the operator interface is supported from a remote location. This single- or dual-loop DIN-rail mount controller offers up to four control/alarm outputs plus up to two digital/current transformer inputs. To support access by remote users, the SERIES PD provides a web server for configuration and operation via a web browser. An e-mail can be sent to service personnel for notifying operators of alarms and other conditions.
Watlows EM gateway offers Ethernet connectivity for existing devices that communicate via the Modbus RTU protocol on an RS-485 network. The EM gateway provides a quick, convenient and economical means of adapting controllers to Ethernet connectivity by bridging communications from Modbus® RTU on RS-485 to Modbus TCP on Ethernet. The EM gateway also acts as a web server for supported temperature controllers, allowing users to remotely monitor the process variables and alarms. The user can remotely set the set points for temperature controller in an Internet browser. Users can receive e-mail messages when alarms occur in supported controllers. The features of Ethernet protocols act as extensions of the user interface, making it more convenient for operators and supervisors to monitor processes and equipment.
For industrial automation solutions the gateway bridges messages from, for example a PLC supporting Modbus TCP on Ethernet to a 485 network of devices communicating via Modbus RTU.
According to the Open DeviceNet Vendors Association (ODVA), the agency that sponsors both the DeviceNet and EtherNet/IP protocols, EtherNet/IP is a member of a family of networks that implements the Common Industrial Protocol (CIP) at its upper layers. CIP encompasses a group of messages and services for manufacturing automation applications including control, safety, synchronization, motion, configuration and information. EtherNet/IP provides users with the network tools to use standard Ethernet technology for manufacturing applications while enabling Internet and enterprise connectivity.
Traditionally, performing temperature control in a PLC can be difficult or can interfere with other program functions, so temperature is often controlled separately from the PLC. But in the past, due to differences in the supported protocols, getting standalone temperature controllers and PLCs to communicate has been time consuming, costly and difficult, says Watlow product manager, Sean Wilkinson. He adds that customers prefer temperature controllers outside of the PLC when performance of control loops is important or when the PLC application could be negatively impacted by incorporating the temperature controller, i.e. where there is significant motion control.
