MTL Instruments MTL647, MTL646 Specifications

IS indicators

MTL646/647 DISPLAYS

◆

IS display certified to ATEX

◆

High contrast LCD with backlight

◆

Communication from a safe area
via a galvanic isolator

The MTL646/647 Serial Text Displays are

intrinsically safe instruments that can display text
and simple graphics in a hazardous area. Having
a number of push-buttons and two solid-state
switched outputs, they provide a low cost operator
interface ideal for simple machine and process
control applications. In addition to new installations,
the legacy protocol enables existing MTL643/644
display systems to be easily upgraded.

Data and power are normally supplied by a 2-

wire serial data link from an MTL5051 isolator in
the safe area. This isolator, which can power and
communicate with up to two MTL646/647 serial
text displays, has a bi-directional RS232 or RS422
safe area port. Alternatively, a 3 wire system may be
used to communicate with up to four MTL646/647
text displays. The high contrast LCD incorporates a
green backlight that is powered by the serial data
link. Brightness and contrast are adjustable enabling
the display to be read in all lighting conditions from
full sunlight to total darkness.

Six push-buttons on the front panel of the MTL646

(four on the MTL647) may be used for operator
acknowledgments or controls. If larger industrial
switches are required, these may be connected to the
text display rear (MTL647–internal) terminals. When
the remote switches are activated, the front panel
push-buttons are disabled automatically.

Two isolated switch outputs, which can control

certified hazardous area loads such as sounders,
lamps and valves, are included.

◆

Operator push-buttons or external
switch inputs

◆

Two switch outputs

◆

IP65 front panel

The MTL646/647 text displays are normally

controlled and interrogated by a safe area process
computer or by a dedicated instrument such as a PLC
or weighing system. The text displays may be used
singly but up to four instruments can be multidropped
on a hazardous area network. At a data rate of
9600 bps, the cable between the safe area galvanic
isolator and the MTL646/647 text display may be
up to 100m long. The protocol, which uses ASCII
characters, enables text to be written anywhere
on the screen in five different font sizes, together
with lines, boxes and bargraphs. Simple bitmap
graphics may be downloaded to the display and all
characters can be reversed or flashed. Information
can also be written to a hidden screen which may
be displayed when required.

Five different operational modes are selectable,

allowing the user to choose the appropriate level of
communications security for each application. These
range from immediate execution of a command with
no message acknowledgement, to a 16 bit CRC.
The communications speed, number of stop bits and
polarity of the parity bit can also be defined.

The legacy protocol enables the MTL646 or

MTL647 to replace an MTL643 or MTL644, in
order to provide certification to ATEX and a display
backlight. No software or galvanic isolator changes
are required and the MTL646 will fit into the existing
panel cut-out. If required, simple modifications to the
driver software will allow the enhanced features of
the MTL646/647 to be used.

EUROPE (EMEA) Tel: [phone] Fax: [phone]
AMERICAS Tel: [phone] Fax: [phone]
ASIA PACIFIC Tel: [phone] Fax: [phone]
E-mail: [e-mail] Web site: www.mtl-inst.com

July 2007

SPECIFICATIONS

Location

Zone 0, 1 or 2

DISPLAY
Type
120 x 64 pixel liquid crystal.
Display Size

86.5mm x 45mm.
Backlight

Powered from serial link.

Characters

ASCII character set, 5 font sizes each with 4 computer definable
soft characters.

Hidden screen

May be written to at any time and displayed when required.

Switch cable length

5m max.

OUTPUTS

Two software controlled switch outputs.

Contacts

Isolated single pole solid state switch (certified as simple
apparatus).
Ron less than 5Ω + 0.7V
R

greater than 1MΩ

off

I.S. parameters

Ui = 28Vdc, Ii = 200mA, Pi = 0.85W

DATA
Transmission Speed

0.3, 0.6, 1.2, 2.4, 4.8, 9.6 or 19.2k bps.*

Cable length between isolator(s) & MTL646/647

100m max at Baud rate of 9.6k bps*
*Depends upon configuration & type of cable - see instruction
manual.

Format

1 or 2 stop bits; odd, even or no parity bit; 7 or 8 data bits.

Protocol

MTL646/647 or MTL643/644.

CONTROLS
Front panel

MTL646: 6 push-buttons which can be software interrogated.
MTL647: 4 push-buttons which can be software interrogated.

Each button function may be displayed on the screen. Buttons
may be disabled.

External switches

Control may be transferred to six external switches; front panel
buttons are inhibited.

ENVIRONMENTAL
Operating temp

–20°C to +60°C (certified for use at –40°C)

Humidity

To 95% @ 40°C

Enclosure

Front IP65
Rear IP20

MECHANICAL
Terminals

Removable with screw clamp for 0.5 to 1.5mm

Weight

MTL646 0.7kg
MTL647 1.6kg

ACCESSORIES
Tag number

Thermally printed strip on rear of instrument.

Programming guide

May be downloaded from http://www.mtl-inst.com

2 cable.

APPROVALS

For the latest certification information visit:
www.mtl-inst.com/certs_1.nsf

MTL646

Country
(Authority)

UK

(ITS to
CENELEC
standards
& ATEX
Directive)

UK
(ITS to
CENELEC
standard)

USA (FM)

Standard Certificate/

EN 50020: 2002
EN 50014: 1997
EN 50284: 1999

EN 50039: 1980 Ex 03E21194

3610 entity 3026711 Class I, Div 1,

3611 non-incendive Class I, Div 2,

file no.

ITS03ATEX21172 Group II

2-wire system
Ex 03E21195
3-wire system
Ex 03E21196
4-wire system

Approved for

Category 1G
EEx ia IIC T5

EEx ia IIC T5

Grps A-D
Class 1, Zone 0
Group IIC

Grps A-D
Class 1, Zone 2
Group IIC

MTL647

Country
(Authority)

UK

(ITS to
CENELEC
standards
& ATEX
Directive)

UK
(ITS to
CENELEC
standard)

USA (FM)

Standard Certificate/

EN 50020: 2002
EN 50014: 1997
EN 50284: 1999

EN 50039: 1980 Ex 03E21194

3610 entity 3026711 Class I,II,III,

3611 non-incendive Class I, Div 2,

file no.

ITS03ATEX21173 Group II

2-wire system
Ex 03E21195
3-wire system
Ex 03E21196
4-wire system

Approved for

Category 1G
EEx ia IIC T5

EEx ia IIC T5

Div 1, Grps A-G
Class 1, Zone 0
Group IIC

Grps A-D
Class 1, Zone 2

Group IIC
Class II, Div 2,

Grps E-G
Class III, Div 2

EUROPE (EMEA) Tel: [phone] Fax: [phone]
AMERICAS Tel: [phone] Fax: [phone]
ASIA PACIFIC Tel: [phone] Fax: [phone]
E-mail: [e-mail] Web site: www.mtl-inst.com

July 2007

MTL646

144

72

11 84

Panel cut-out

Recommended panel cut-out

DIN 43 700

138.0 +1.0/ -0.0 x 68.0 +0.7/ -0.0

To achieve an IP65 seal between
the instrument and the panel

136.0 +0.5/-0.0 x 66.2 +0.5/-0.0
Four panel mounting clips must
be used

MTL646

This instrument can

display text in
five font sizes

Information

Two M6 clearance
holes for surface
mounting

141

212

117

72

P

E

Three 22.25 Æ holes
for cable entries

91

Information

This instrument can

display text in
five font sizes

S1 S2S3 S4 S5S6 S7

1

2

3

4

5

6

3
2

13
14

20 to
35V dc

+

MTL5051

RS232
or
RS422

Safe areaHazardous area

Optional external switches

2-wire system for 1 or 2 text displays

MTL646

S1 S2S3 S4 S5S6 S7

1

2

3

4

5

6

2
3

13
14

20 to
35V dc

+

MTL5051

RS232
or
RS422

Safe areaHazardous area

Optional external switches

2-wire system for 1 or 2 text displays

P

E

6

5

4

3

2

1

S7 S6S5 S4 S3S2 S1

P

E

6

5

4

3

2

1

S7 S6S5 S4 S3S2 S1

DIMENSIONS

MTL647

DIMENSIONS

TERMINAL CONNECTIONS

Case

1 2 3 4 56

V+ 0V V

sig

S1 S2 S3 S4 S5S6 S7

Tx Rx

CONNECTIONS

EUROPE (EMEA) Tel: [phone] Fax: [phone]
AMERICAS Tel: [phone] Fax: [phone]
ASIA PACIFIC Tel: [phone] Fax: [phone]
E-mail: [e-mail] Web site: www.mtl-inst.com

Case

A1

External switches

A2 A3A4

+

Switch outputs

TERMINAL CONNECTIONS

Case

6 5 4 3 21

sig

S7 S6 S5 S4 S3S2 S1

V+0VRx Tx V

External switches

A3

A4 A1A2

+

Switch outputs

+

CONNECTIONS

+

July 2007