LCD
The 7-segment LCD, with additional characters and symbols, complies with the VDEW specifications. Large
characters and a wide angle view enable easy data reading. The LCD back-light illumination is available
on request. The LCD is illuminated by short (Tp < 2 s) pressing the blue pushbutton. On request the back-light is
turned-on all the time.
LCD
Data are displayed in the right-side by means of eight alphanumeric characters. The size of data characters is 8
mm high and 4 mm width. The OBIS code (by IEC 62056-61), without the first two characters from the left side,
is employed for data identification. It is displayed in the left side corner by means of five 6 mm high
alphanumeric characters.
An indicator of energy flow direction is displayed in the left top corner.
Note: If there is no load or the load current is lower than the meter starting current, the indicator
of energy flow direction is not displayed.
A physical unit of displayed physical quantity is shown in the right top corner. The indicator of L1, L2, L3
phase voltages presence is displayed in the middle of the top row. If certain phase voltage is not present, the
indicator of that phase is not displayed.
When the indicators L1L2L3 blink, this indicates wrong phase sequence.
When the indicator L1, L2 or L3 blinks and at the same time the arrow
←
indicating export energy flow direction
is displayed, it indicates reverse energy flow through the metering element in that phase. In the LCD bottom
row there are eleven signal flags that indicate current valid tariff, meter status and alarms. The meaning of
signal flags (see item 2.5.3) is engraved on the meter name plate below them.
DATA DISPLAY
Data defined in Auto scroll sequence and in Manual scroll sequence are displayed on the LCD.
Data from Auto scroll sequence are displayed in a circle, and each data is displayed for 8 seconds as a
standard (default) display time.
At Manual scroll sequence the blue push-button should be pressed for displaying the next piece of data. Data in
Manual scroll sequence remains displayed until the push-button is pressed again or until time for automatic
return into the Auto scroll sequence is elapsed.
SIGNAL AND ALARM FLAGS
The signal flags in the LCD bottom row indicate certain meter status and alarms. They are grouped into three
groups:
•
actual tariff (first four flags on the left side)
•
alarms (four flags in the middle)
•
meter status (last three flags on the right side)
The MT174 meters enable indication of many different alarms but only four of them can be displayed on the
LCD. If more than four alarms are to be indicated on the LCD, one signal flag can be used for two different
alarms (e.g. one signal flag for both the meter cover and the terminal cover opening)
