Sept 2002 EUROPE (EMEA) Tel: +44 (0)1582 723633 Fax: +44 (0)1582 422283 AMERICAS Tel: +1 603 926 0090 Fax: +1 603 926 1899 ASIA PACIFIC Tel: +65 487 7887 Fax: +65 487 7997 E-mail: enquiry@mtl-inst.com Web site: www.mtl-inst.com 1 Module carriers - Overview General Carriers are the building blocks on which the MTL8000 system is assembled. They distribute the basic power supply services to the modules, and provide the communications route between the Bus Interface Module (BIM) and I/O modules. Carriers can be mounted on DIN rail or directly to a flat surface and may be joined end-to-end to extend the size of an installation. Multipin connectors at the end of each carrier carry the system power supply and internal “Railbus” communications across to the next carrier. All I/O module carriers have their own independent earthing/ grounding strip, with screw terminals, to terminate the screens/shields of field-wiring cables. At each end of the strip there is a separate terminal to enable it to be linked to other carriers, or to the system ground, as required. Node services carrier-NSM This node services carrier will accommodate one BIM and a node services module. It is the recommended BIM carrier for all AC powered nodes because it supports “power health” management. This carrier will support Modbus or Profibus-DP BIMs. It is also recommended for DC powered nodes that are exclusively 2/1, i.e. where no 2/2 I/O modules are required. For these applications, it is commonly used with the power supply carrier (see this page) . BIM-only carrier This carrier provides an alternative to a node services carrier - NSM when a node services module is not required. This carrier will support Modbus or Profibus-DP BIMs. It is commonly used with the power supply carrier (see this page). Node services carrier-BIM These two node services carriers will accommodate one BIM, a node services module, two system DC power supplies and four 2/2 I/O modules. One carrier (8711) supports the Modbus BIM and the other (8712) supports the Profibus-DP BIM. These carriers are recommended for DC powered nodes that use 2/2, or a mixture of 2/2 and 2/1 I/O modules. I/O Module carriers I/O Module carriers are available in general purpose (2/2) and 2/1 format. As a safeguard, these two types cannot be connected to each other because of the different multipin connectors used. The only way to connect the two types is by placing a Railbus Isolator (on its carrier) between them. Within each format, 4 and 8 module carriers are available and they may be joined in any combination to suit node requirements. Power supply carrier This carrier is used to mount the 8910-PSDC system power supply module which provides system power for DC power nodes. It is often used to support the node services carrier-NSM or the BIM-only carrier. IS power supply module carrier The 8920-PS-DC field power supply module provides power for 2/1 I/O modules and requires its own carrier to mount it. The carrier mounts in-line with 8- and 4-module 2/1 carriers, maintaining the Railbus connections through its edge connectors. Railbus isolator carrier When a node has intrinsically safe field wiring terminating on it, an 8922-RB-IS Railbus isolator must be used between 2/2 and 2/1 carrier types. This is to prevent possible mains-voltage fault conditions from being propagated, via the Railbus, to the IS field wiring. The Railbus isolator has its own carrier – 8723-CA-RB. Carrier extenders If the chosen field enclosure will not accommodate a single, end to end line of carriers, extenders can be fitted to enable the carriers to be continued on another line. The extenders are left and right handed and connect to the ends of the I/O module carriers using the multipin connectors. A multicore cable is used to link the data and address bus between the carriers. General purpose (2/2) and 2/1 extenders have different connectors to prevent accidental cross connection of the two types.

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