IM 61A01A01-01E-A
2nd Edition
Model MLD (Digital
Model MLA (Analog)
Model MLA & MLD
User’s
Manual
Loop Powered Process Indicators
IM 61A01A01-01E-A
)
IM 61A01A01-01E-A
Model
Suffix
Codes
Description
……………….
-A …………..
-C …………..
4 to 20 mA DC
1 to 5 VDC (MLA only)
2 ………..
2” Vertical Pipe (or wall mount)
/CF1
CSA Explosion Proof
Scale
Scale in Engineering units (MLA Only)
/SST
/SSW
Stainless Steel tag screw att ac hed to housing
Stainless Steel tag wired to housing
/0
ANSI ½ NPT female, without blind plugs
Temperature
/T1
Low-Temperature (-50°C, MLA only with Option CF1)
1. PREFACE
The Model MLA and MLD field mounted indicators receive DC voltage or current signals from 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 SPECIFI CATIONS
STANDARD
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 typ., 2V max. (MLD)
Scale: Black. Analog single graduations 0-
100% standard. Digital 0-100.0% w/decimal
standard.
Accuracy: ± 1.5% of full scale (MLA)
± 2.0% of full scale (MLA with /T1 Option)
± 0.05% of full scale (1999) ±1 count (MLD)
Operating Temperature Range:
-50 to 60°C (MLA with Options /CF1 and /T1)
-20 to 60°C (MLA/MLD with all other Options)
Temperature
Insulation
terminals and case 100 Mohm at 500 V DC
Dielectric
and case: 1000 VAC for 1 minute.
Mounting:
surface.
Explosion Protection Type
EXPLOSIONPROOF
A,B,C,D,
GROUPS E,F,G
Case and Cover: Die cast aluminum, baked
polyurethane paint. Moss Green; NEMA 4X
Electrical
M20 x 1.5
Weight: 3.0 lbs (MLA), 2.7 lbs (MLD)
drift: ±0.3 Count/°C (MLD)
Resistance: Between input
Strength: Between input terminals
Nominal 2” (50mm) pipe mount or
DUST-IGNITIONPROOF
Connection: ½ x 14 NPT or
SPECIFICATIONS
: FM, CSA,
CL1, DIV1, GROUPS
CLII / III,
MODEL MLA &
MLA
MLD
Input Signal
Mounting
Ex Protection
Calibration /ENG Engineering Unit Calibration (MLD Only)
Face plate
Stain Steel Tag
Electrical
Connection
Coating
Paint
MLD
……………….
-B …………..
1..............
/FF1
/WHT
/SC
/1
/2
/3
/4
Field Mounted Loop Indicator (Analog)
Field Mounted Loop Indicator (Digital)
10 to 50 mA DC (MLA only)
2” Horizontal Pipe
Optional Specifications
FM Explosion Proof
White scale or face plate (MLA Only)
ANSI ½ NPT female, 304 Stainless Steel blind plugs
ANSI ½ NPT female, 316 Stainless Steel blind plugs
ISO M20 female, without blind plugs
ISO M20 female, 316 Stainless Steel blind plugs
/X1
Epoxy resin coating
Polyurethane-Epoxy Anti-corrosion coating
/X2
/P1
Light Blue (RAL # 5012)
Orange (RAL # 2008)
/P2
/P3
Red (Munsell # 7.5 R4/14)
Mint Green
/P4
/P5
Silver (RAL # 9006)
Yellow (RAL # 1018)
/P6
/P7
Gray (RAL # 7046)
IM 61A01A01-01E-A
OPTIONS
Scale: MLA: Special range scale in Engineering Units (/SC).
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 (attached or wired to housing), Electrical Connections,
SUS316 Housing, /X1 or /X2 coatings and Paint.
ORDERING INSTRUCTIONS
1. Model and Suffix codes.
2. Option Codes
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
IM 61A01A01-01E-A
3. INSTALLATION
The Loop Powered Indicator can be mounted on a wall or a 2” pipe. The housing is a Nema4X Explosion
Proof housing so it can be mounted outside in the field.
Do not install the unit in the following conditions:
• Extreme Temperatures beyond the temperature rating of the instrument.
• High vibration areas above the vibration rating of the instrument.
• Extremely corrosive environments.
MOUNTING EXAMPLES
IM 61A01A01-01E-A
4. WIRING
The loop powered indicator series is powered by the current output loop and does not require external
power. All devices must be wired in series with the current loop. Twisted pair shielded cable is
recommended.
The following is a typical wiring example of the MLA (Analog type) Loop Indicator connected to an
EJA Pressure Transmitter. The impedance of the MLA is low enough that you can connect it
across the Check Terminals
The following is another wiring example of the MLA (Analog type) or MLD (Digital type) Loop Indicator connected to an EJA
Pressure Transmitter (Note: The EJA Transmitter below can be replaced with any 4-20mA 2 wire device.
The Loop Indicator is available in FM Explosion Proof and CSA Explosion Proof types for hazardous
locations. Wire sealing is required for these approvals. The following diagrams show some wire sealing
IM 61A01A01-01E-A
examples.
For Flameproof type use Flameproof Packing Adapter or Flameproof Conduit in connection above.
MOUNTING IN HAZARDOUS LOCATIONS
IM 61A01A01-01E-A
IM 61A01A01-01E-A
5. CALIBRATION
Suffix –A
4-20mA
Suffix –B
10-50mA
Suffix –C
1-5V
0%
4.0mA
10mA
1.0VDC
20%
7.2mA
18mA
1.8VDC
40%
10.4mA
26mA
2.6VDC
60%
13.6mA
34mA
3.4VDC
80%
16.8mA
42mA
4.2VDC
100%
20.0mA
50mA
5.0VDC
The Loop Indicators are factory calibrated to 0-100% unless the /SC (for MLA) or /ENG (for MLD)
options are specified.
Calibration check for MLA Analog Type Units
(1) The MLA model ships with a 0-100% scale unless ordered with the /SC Special Scale option.
(2) Connect unit to Voltage/Current Standard (red to +, black to -). Voltage/Current Standards can be
purchased through Yokogawa Corporation of America. Recommended models are CA11
(Voltage/Current Calibrator) or CA71 (Multifunction Calibrator).
(3) The values to check are shown in the table below. Apply the minimum value and adjust the zero
manually first. The zero adjustment can be performed by using a special tool or small needle nose
pliers and twisting the white Teflon piece in the center of the meter element. Be careful not to
damage the meter movement.
(4) Verify the meter readings are within specification.
Calibration of MLD Digital Type Units
(1) The MLD model ships with a calibration range of 0-100% unless ordered with the /ENG
Engineering Units option.
(2) If adjustments are needed the 2 screws holding the plate will need to be removed
(3) Connect unit to Voltage/Current Standard (red to +, black to -). Voltage/Current Standards can be
purchased through Yokogawa Corporation of America. Recommended models are CA11
(Voltage/Current Calibrator) or CA71 (Multifunction Calibrator).
(4) Set range switches based on the following table (for standard 0-100% unit set SW1 and SW8 to
ON):
IM 61A01A01-01E-A
Desired Display Reading
4mA
Adjustment
20mA
Minimum
20mA
Maximum
SW1
SW2
SW3
SW4
SW5
000
1200
1999
OFF
OFF
OFF
OFF
OFF
000
600
1200
ON
OFF
OFF
OFF
OFF
000
400
600
OFF
OFF
ON
OFF
OFF
000
200
400
ON
ON
ON
OFF
OFF
000
100
200
ON
ON
ON
ON
OFF
Suffix –A
4-20mA
Suffix –B
10-50mA
Suffix –C
1-5V
0%
4.0mA
10mA
1.0VDC
25%
8.0mA
20mA
2.0VDC
50%
12mA
30mA
3.0VDC
75%
16mA
40mA
4.0VDC
100%
20mA
50mA
5.0VDC
Adjustment
Adjustment
(5) Set the Decimal value as follows:
a. If tenths (ex. XXX.X) set SW8 on.
b. If hundredths (ex. XX.XX) set SW7 on.
c. If thousandths (ex. X.XXX) set SW6 on.
(6) The values to check are shown in the table below.
(7) Set the voltage standard to the 0% value. Adjust the Zero Pot (top one) to read the minimum value
needed.
(8) Set the Voltage Standard to the 100% value. Adjust the Span Pot (bottom one) to read the
maximum value needed.
(9) Check all points in the table above and verify unit is within specification.
IM 61A01A01-01E-A
6. ROTATING DISPLAY DIRECTION
The loop indicator display is designed so that it can be rotated in 90 degree increments. This is
accomplished by ordering the unit as a horizontal pipe mount or a vertical pipe mount. However there
may be the need for the customer to change the angle of the display. The following are procedures for
the display rotation:
Display rotation of MLA Analog type
WARNING: The MLA loop indicator contains a very delicate meter movement which can easily
be damaged if care is not taken. When performing the following modification avoid contact with
the pointer and any of the internal meter movement to avoid damage.
(1) Remove power from the unit.
(2) Remove the glass cover from the display side.
(3) Remove the 2 small screws holding the scale plate onto the meter.
(4) Carefully remove the scale from the unit (avoid touching the pointer).
(5) You will notice 2 screws at the 9 and 3 o’clock positions in the bottom of the housing. Remove
these screws.
(6) Rotate the meter to the position desired.
(7) Replace screws in the 9 and 3 o’clock positions and tighten firmly.
(8) Carefully put the scale back on the unit (avoid touching the pointer).
(9) Replace the 2 scale mounting screws.
(10) Replace the glass cover.
Display rotation of MLD Digital type
(1) Remove power from the unit.
(2) Remove the glass cover from the display side.
(3) Remove the 2 screws holding the mounting plate to the standoffs.
(4) Rotate the display to the desired position (can be rotated in 90 degree increments).
(5) Replace and tighten firmly the 2 screws into the standoffs.
(6) Replace the glass cover.
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