User’s Manual Model MLA & MLD Loop Powered Process Indicators IM 61A01A01-01E-A Model MLD (Digital) Model MLA (Analog) IM 61A01A01-01E-A 2nd Edition
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 SPECIFICATIONS STANDARD SPECIFICATIONS MODEL MLA & MLD 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.
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.
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.
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.
examples. For Flameproof type use Flameproof Packing Adapter or Flameproof Conduit in connection above.
IM 61A01A01-01E-A
5. CALIBRATION 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.
Desired Display Reading 4mA 20mA Adjustment Adjustment Minimum 000 1200 000 600 000 400 000 200 000 100 20mA Adjustment Maximum 1999 1200 600 400 200 SW1 SW2 SW3 SW4 SW5 OFF ON OFF ON ON OFF OFF OFF ON ON OFF OFF ON ON ON OFF OFF OFF OFF ON OFF OFF OFF OFF OFF (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.
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.
