Low cost communicator anticipates trouble

Tom Shelley reports on a small clip on module that turns an overload trip into a sophisticated monitoring device

Rockwell Automation has just brought out a small, low cost DeviceNet module that clips onto the side of a standard overload relay and can advise of potential problems before they lead to breakdown. The 193-EDN Starter, or DeviceNet Starter Module mounts directly onto an E1 Plus unit, and can be used to transmit not only information about rising currents or percentage of thermal capacity likely to lead to an overload, but also low currents indicating underloads. Overloads tend to indicate that something has got stuck, but underloads indicate situations such as load drive shaft failure, pumps running dry, or loss of a conveyor belt. Only 18mm wide, it is designed to report to a PLC, PC or HMI, which can in turn connect to a wider automation line or plant control system. The current range 0.1 to 800A is covered by five overload relays and one 193-EDN. Entry price is only about £20, on top of a typical £40 for a circuit breaker and overload relay, so it is an exceptionally low cost way of being made aware of what may be very expensive damage about to occur. Rockwell Automation