Eaton MTL831B IS analogue multiplexer transmitter

Product description

The MTL831B analogue transmitter can transfer a number of

hazardous area input signals to the safe area down a data highway

consisting of a single twisted pair cable. It is intrinsically safe and can

therefore be mounted in Zone 0 hazardous areas or Class I, Division

1 hazardous locations.

The MTL831B can monitor up to 16 inputs from THC or millivolt

sources or up to 15 inputs from 2. 3 or 4-wire RTDs.

Two (i.e. dual redundant) data highway outputs are provided that can

carry both signal and power over distances up to 3km, depending on

the application, the cable and the (noise) environment - see Section

4.4. The highway cables can be simple twisted-wire pairs or pairs of

wire within an IS multi-core cable.

At the other end of the data highway, MTL838B-MBF receivers are

used to translate the information transmitted from the MTL831B. The

MTL838B-MBF provides a Modbus®serial data output representation

of the inputs together with status information.

When the MTL831B transmitter is mounted in the hazardous area,

each data highway mustbe protected by an MTL3052 digital isolator

mounted in the safe area.

GETTING STARTED

Installation of the MTL831B multiplexer transmitter is divided into

three main topics.

♦ Mechanical Installation - how to mount the MTL831B and

how it may be fitted into our enclosure.

♦ Electrical Connections - the sensor and highway

connections. If units are installed in our enclosures, it details any

special wiring arrangements.

♦ Configuration-  the address and input mode selection by the

setting of internal switches.

Note:  A new user might find it helpful to set up the system, or a

simple version of it, in an indoor test area to gain familiarisation

before undertaking installation on site.

MECHANICAL INSTALLATION

Location

The MTL831B can be installed in either safe or hazardous areas

(including Zone 0 or Division 1) depending upon the requirements of

the application.

Mounting options

The unit can be mounted on T-section DIN-rail or onto a flat surface.

Eaton has a range of enclosures - ENC8. ENC8-SS, ENC83 or

ENC83-SS - to provide suitable IP67 protection if the transmitter is

located in an exposed area.

Mounting on T-section DIN-rail (Figure 1)

Hook the side opposite the central mounting clip onto standard 35mm

DIN46277 T-section rail and push downwards until the unit clicks into

place.

To remove, ease the central clip below the base of the unit outwards

(with a screwdriver) and unhook the clips on the other side.

Mounting on a flat surface (figures 2 and 3)

Turn the unit upside down.

With a screwdriver, apply an anti-clockwise force against the

retaining arm of one of the base clips to release it from its recess.

Hold the arm in this position and slide the clip outwards.

Release the retaining arm to engage the tooth in the base moulding.

Adjust the position of the other two clips with a similar procedure.

Mount on any flat surface using three M4 bolts or screws (or other

suitable fasteners with a shank diameter of 4mm or less) through the

three clips according to the mounting centres shown in figure 3.

Mounting in an ENC8. ENC8-SS, ENC83 or

ENC83-SS enclosure (figure 4)

Remove the upper and/or lower undrilled gland plates and drill

suitable holes for the entry glands required. Possible hole

configurations are listed in the table.

Mount the unit on the internal T-section rail of the enclosure as

described in (1).

Mount the enclosure on any flat surface using four M8 bolts (or other

suitable fasteners with a shank diameter of 8mm or less) through the

four fixed lugs according to the mounting centres shown in figure 4.