Yokogawa MLD - Manual (Page 8)

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. 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
.
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
(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):