Intrinsically Safe Text Displays

MTL643/644 DISPLAYS
Intrinsically Safe Text Displays

Alphanumeric displays in hazardous areas Large LCD alphanumeric display Point to point or multidrop communication with PC, PLC or simple host RS232 or RS422 in safe area Easy to configure simple ASCII communication Tough impact-resistant field unit with separate terminal compartment DIN-standard panel-mounted version

The MTL643/4 IS text displays are located in the hazardous area where they display alphanumeric data from a safe-area host controller. This is transmitted by a serial data link passing through an MTL5051 isolating interface. This serves the dual purpose of isolating the IS indicator and converting RS232 or RS422 serial data to the MTL signal level and vice versa. Bi-directional communication permits operators to acknowledge messages and to request process action when necessary. If required, an audible or visual alarm can be connected to attract the operators attention.

A clear and unambiguous alphanumeric display is provided by liquid crystal module with two lines of up to sixteen 9mm high characters. All 32 characters may be alphanumeric so process values,engineering units, tag idents and operator messages are easily displayed.

Operator control is provided by three external switches (not supplied) which are connected to terminals on the indicator and which can be used to acknowledge alarm messages and change process information such as the resetting of the tare in a weighing system.

The controller maintains master control, requiring all remote display units to respond to its commands. In multi-indicator applications, it transmits a block of information which includes the indicator type, address and data. Data is transmitted in the form of ASCII characters interpreted by the appropriate ndicator which either updates the display or responds with a reply such as indicator status or switch status. In single indicator applications, the protocol may be simplified to direct data transmission for communication with less sophisticated host units including PLCs, dedicated control instrumentation and weighing systems.

A single alarm output (an opto-isolated open collector transistor output) is provided for connection to a suitable visual or audible alarm unit to attract the operator's attention.

Error checking routines are carried out by the indicator, the result being stored in the status data register where it can be accessed by the host computer.

MTL643 field mounting unit is housed in a tough impact-resistant GRP case designed to withstand the rigours of hostile weather conditions and harsh industrial environments. Ingress protection rating is IP66. It can be mounted directly onto a flat surface or with an optional PIP68 kit, onto vertical or horizontal pipes or posts.

MTL644 panel mounting unit is designed for DIN standard 72 x 144mm cut-out. The front panel fascia is protected to IP65 while, with standard 'snap-on' mounting clips, the panel/unit seal is rated IP40. This can be uprated to IP65 with the optional IPK68 sealing kit.

Data Sheet