This unprecedented flexibility comes from characterization module (CHARM) technology, which allows field wiring of any signal type to be terminated anywhere. A CHARM is simply a single-channel component with an A/D converter and signal characterizer inserted onto the terminal block where field wires are landed. Each device can be landed anywhere on the strip regardless of its signal type: AI 4-20mA, AO 4-20mA, AI 0-10V, TC, RTD, DI Dry or Namur, DO High Side, Relays Contact Outputs or Isolated DI and DO for higher currents or higher VAC Voltages. Simply click in a CHARM with the corresponding signal type, and the landing is done. After the CHARM is in place, the channel is electronically marshaled to any controller in the system. This means no marshalling cabinet or cross-wiring, fewer wires, much less work, and fewer contact points for potential failures.
Electronic marshalling and the CHARM technology have proven thier flexibility in installations, delivering up to 50% wiring savings over traditional wiring as well as eliminating traditional marshalling cabinets and cross-wiring. At the same time, they increase reliability while reducing maintenance costs, responding quickly and easily to late changes with no impact on startup scheduling.
Intrinsically Safe CHARMs
The addition of intrinsically safe (IS) CHARMs provides significant savings with Electronic Marshalling, with the added intrinsically safe circuitry for field wiring into hazardous areas, including Zone 1, Zone 0 or Class 1 Div1. I/O in hazardous areas traditionally requires costly explosion-proof mounting or isolation barriers, along with added space for barrier and termination, and ongoing maintenance to ensure compliance with safety requirements. IS CHARMs deliver a reduced footprint and eliminate the need for separate barriers and the associated inter-cabinet wiring. A smaller footprint and fewer connections improve reliability and deliver significant cost savings.
IS barriers are integrated inside the IS CHARM to provide single channel fault isolation, as well as electrical isolation and energy limiting circuitry that meets IEC Ex ia ratings. First available IS CHARMs signal types are: IS AI 4-20mA HART, IS AO 4-20mA HART, IS DI Namur, and IS DO 24 VDC.