Rel-Tek offers several stand-alone systems with monitoring and control functions. These units are available with displays, and relay outputs. The PLC Express is expandable to work with the Millennia/DX System. The RMcalibar is UL approved and has I.S. barriers. The Telecon-400 is modular system incorporating several different enclosures and power supplies, along with being able to monitor up to 8 sensors and having up to 16 output relays. The Telecon-400 and RMcalibar use the RM420i module. This module also has the ability to let the 4-20mA signal flow through to another monitoring device if need be, such as a recorder or data logger. RM420i gives you the peace of mind if for some reason your remote monitoring were to fail this unit can do the controls locally.