Yokogawa MLX - Manual (Page 33)

Page 33 of 49
IM 60A02S01-01E-A
5. Operation
5.1 Overview
The MLX is loop powered. Connect it in series with a 4-20mA loop as per Section 4 “Wiring”.
Observe correct polarity as the indicator is protected against reversed connections but will not
display a reading. After properly connecting the indicator to a transmitter or other 4-20mA
source, the display will indicate the value of the current flowing in the loop (0-100% for the
standard model or other specified engineering units can be user defined).
IMPORTANT
Connecting directly across a 24 V supply without a transmitter or similar device to
regulate the loop current will result in damage to either the power supply or the MLX.
The MLX can easily be ranged to display virtually any engineering units by properly calibrating
and selecting the desired units to be displayed.
The MLX uses a 4-key touchpad for operator input. Each key may have multiple functions
assigned to it based a particular menu operation. These keys allow the user to access setup
parameters, enter engineering units, zero and full-scale values, select display symbols and
modify display functions. Figure 5.1 illustrates the keyboard.
Figure 5.1 MLX 4-key Touch keypad.
Each key serves to navigate the menu systems and select a particular value or function. The
overall function of each key is shown in Table 5.1.
Table 5.1
MLX key functions
Key Function
Selects the previous menu item or menu level
Selects the next menu item or menu level
Selects the current menu item or menu level
Exits the menu item or menu level and returns the MLX to normal functions.