Yokogawa MLA Operating Manual

User’s
Manual

Model MLA & MLD

Model MLD (Digital) Model MLA (Analog)

Loop Powered Process Indicators

1. PREFACE

The Model MLA and MLD field mounted indicators receive DC voltage or current
signals by electronic transmitters and indicate process measurement values. This
instruction manual gives instructions on handling, mounting, and wiring of the MLA
(analog type) and MLD (digital type) indicators.

2. MODEL CODE AND SPECIFICATIONS

Model Suffix Codes Description
MLA ………………. Field Mounted Loop Indicator (Analog)
MLD ………………. Field Mounted Loop Indicator (Digital)
Input Signal -A ………….. 4 to 20 mA DC

-B ………….. 10 to 50 mA DC (MLA only)

-C ………….. 1 to 5 VDC (MLA only)

Mounting 1.............. 2” Horizontal Pipe

2 ……….. 2” Vertical Pipe (or wall mount)
Housing /1……….. Cast Aluminum Alloy –(Standard Housing)
/2……….. SUS316 Cast Stainless and ASTM CF-8M
(/FF1 and /CF1 are pending.)
Electrical /00……..  NPT Female; No Plugs
Connection /10……..  NPT Female; (2) 304 SST Blind Plugs
/20……..  NPT Female; (2) 316 SST Blind Plugs
/30…….. M20 Female; No Plugs
/40…….. M20 Female; (2) 316 SST Blind Plugs
Explosion
Protection /CF1 CSA Explosion Proof
Paint Option /X1 Epoxy Resin Paint
/X2 Polyurethane-Epoxy(Anti-Corrosion Paint)
Options /E NG Engineering Unit Calibration (MLD Only)
/ WHT White scale or face plate (MLA Only)
/ SC Scale in Engineering Units (MLA Only)
/ SST SST Tag - Attached to Housing
/SSW SST Tag – Wired to Housing

/FF1 FM Explosion Proof

STANDARD SPECIFICATIONS
Input Resistance: < 6.5 ohm (MLA-A 4-20mA), < 13.5 ohm (MLA-B 10-50mA),

~4K ohm (MLA-C 1-5V)

Voltage drop: 1.8V typical, 2V max. (MLD)

Scale: : Black. Analog single graduations 0-100% std. Digital 0-100.0% w/decimal std.

Accuracy: ± 1.5% of full scale (MLA), ± 0.05% of full scale (1999) +1 digit (MLD)

Operating Temperature Range: -20 to 60°C
Temperature drift: ±0.3digit/°C (MLD)

Vibration: 1G @ 10-150Hz (MLA), 3G @ 10-150Hz (MLD)

Insulation Resistance: Between input terminals and case 100 Mohm at 500 V DC

Dielectric Strength: Between input terminals and case: 1000 V AC for 1 minute.

Mounting: Nominal 2” (50mm) pipe mount or surface.

Electrical Classification: NEMA4X, FM, CSA, EXPLOSIONPROOF CL1, DIV1, GPS

A,B,C,D, DUST-IGNITIONPROOF CLII / III, GPS E,F,G

Case and Cover: Die cast aluminum, baked polyurethane paint. Dark green. NEMA4X ;
Optional SUS316 Stainless Steel

Electrical Connection: ” NPT or M20

Weight: 3.0 lbs (MLA), 2.7 lbs (MLD) – Based on Standard Housing

OPTIONS

Scale: MLA: Special range scale in Engineering Units (/SC).

MLD: Custom lasered faceplate available on request. (/ENG)

Scale or Faceplate color: White on request (/WHT)

Scaling: Digital: Special calibration in Engineering Units (/ENG). Max. value = 1999

Other Optional Items: Stainless Steel Tag, Electrical Connections, SUS316 Housing,

and /X1 or /X2 Paint. /SST (limited to 12 Characters) or /SSW Tag.

ORDERING INSTRUCTIONS

1. Model and Suffix codes.

2. Option Codes

3. Scale range and unit markings desired.

4. Tag number.

Example Ordering Instructions:

MLD-A1/1/00/FF1/ENG/SST (Field Mounted Indicator (Digital), 4 to 20 mA DC, 2”
Horizontal Pipe, FM Explosion Proof,

0-200 InH2O scale in Engineering Units.) Please specify Scale and Engineering
units when ordering /ENG.

FT-201 Specify Tag Number when ordering /SST; Up to 12 Characters.

DIMENSIONS