MTL 661 Loop-powered indicators for hazardous areas,MTL661 Field No Aluminium 825g A

The MTL661, MTL662, MTL663 and MTL665 digital indicators enable process variables to be displayed locally in hazardous and general purpose plant areas. A typical example would be the re-transmission of mass/flow computations from the safe area, through a suitable MTL IS interface to the indicator in the hazardous area.

The displays are loop powered from the 4-20mA process signal and their low voltage drop allows them to be installed in almost any 2-wire, 4–20mA transmitter loop.

All units can indicate measured values in a linear or a square root extraction mode; the latter being used, for example, to display flow from differential pressure measurement devices such as orifice plates, Dall tubes, or venturi.

The MTL661 Field mounting unit is housed in a tough aluminium enclosure, suitable for wall or pipe mounting. For corrosive atmospheres use the MTL663 - the plastic case provides excellent resistance to harmful contaminents. The MTL665 is the panel mounted version and is IP65, IP66, IP67 and NEMA4 rated.

MTL66x IS indicators are classified as ‘non-energy storing’ simple apparatus so they can be inserted into any IS loop without recertification

SPECIFICATION OF MTL661

Unit location

Zone 0, IIC, T4 hazardous area

Display

5½ digits - 26mm height (process value)

Eleven 8mm digits (process units & current)

Voltage requirements under all conditions

<1V, loop powered

Ambient Temperature

Operating: –25°C to +70°C

Storage: –40°C to +80°C

Humidity

5-99%RH

Input range

4-20mA

Over-range

200mA maximum without damage

Display Range

–99999 to 199999 (Configurable)

Number of digits after decimal point configurable

Zero and span

Setting: anywhere in range

Scale direction

Normal or reverse: software selected.

Out of range indication

"----- RANGE ERROR" displayed between 3.5 - 3.75mA

"99999 RANGE ERROR" displayed at current >22mA

Operating modes

Linear or square root extraction is software selectable.

Accuracy at 20°C

± 0.01mA

Effects of temperature on accuracy

Zero: ± 0.0025% of span /°C

Span: ± 0.01% of span /°C

Ripple rejection

<0.01mA error with 1mA peak to peak ripple at 50Hz

Electrical safety

The input circuit of the indicator is designed such that it does not

influence the intrinsically safe circuit to which it is connected. (In

the USA the application is covered by the entity concept.)

Input circuit (terminals 4 & 5) in type of explosion protection

intrinsically safe Ex ia IIC, with the following parameters:

Ui=30V, Ii=200mA, Pi=1.2W, Ci=0nF, Li=0mH only for

connection to a certified intrinsically safe circuit not exceeding

these values.

Backlight (see Ordering Information & final page for details)

Separately powered backlight from an IS power source

(Uo = 28V, Io = 200mA, Po = 0.96W max.)

MTL661 Field No Aluminium 825g A

MTL661B Field Yes Aluminium 825g A

MTL662 Panel No Aluminium 425g B

MTL662B Panel Yes Aluminium 425g B

MTL663 Field No GRP 500g A

MTL663B Field Yes GRP 500g A

Windy Wang 
HONGKONG XIEYUAN TECH CO., LIMITED  
Add: 7-A16,Caishen Commercial Plaza,Hankou Railway Station,Wuhan,China
Tel: +86-27-8588 3233 | Fax:+86-27-8530 9780 | Mobile/Whatsapp :+86 15972199006 | Skype: windy@hkxytech.com
Mail: windy@hkxytech.com 
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