Yokogawa MLX - Manual (Page 41)

Page 41 of 49
IM 60A02S01-01E-A
6. Maintenance
6.1 Overview
The electronics of the MLX is maintenance free. This chapter describes the procedures for
calibration and rotating the display within the enclosure. Please carefully and thoroughly read the
following sections for information on how to perform these maintenance procedures.
6.2 Calibration Instruments Selection
Table 6.1 lists the instruments that can be used to calibrate the MLX. When selecting an
instrument, consider the required accuracy level. Exercise care when handling these instruments
to ensure they maintain the specified accuracy.
6.3 Calibration
The MLX is factory calibrated to 0-100%. Products ordered with the /ENG Engineering Units
option other than 0-100% use 0-100% as the basis for the desired engineering units. Use the
procedure below to check instrument operation and accuracy during periodic maintenance or
troubleshooting.
(2) Connect the instruments as shown in Figure 6.1 (red wire to + OUT on current source,
black wire to - OUT on current source) and warm up the instruments for at least five
minutes.
Table 6.1 Instruments Required for Calibration
Name Yokogawa-recommended Instrument Remarks
Current Standard Model CA150 Calibrator
or
Model CA450 Process Multimeter
4-20mA source
Current Source
MLX Loop Indicator
Figure 6.1 Calibrating the MLX
+ (Out)
- (Out)
+ (Red)
- (Black)