Ultrasonic Level Transmitter
ULM84 Series User Manual
Dec.2020
Page 11 of 21
FAHM Co.
Industrial Automation
Doc. ULM84 Rev.99-12
10.
Basic Menu (Password: 01000)
In the previous section, a list of basic and advanced transmitter settings was seen; in this section, the basic
settings will be explained in more detail and with details about each of the menus.
To enter this menu, after pressing the ENT key, the Password page will open with the default password
"00000". By changing this number to "01000" and pressing the ENT key, we will enter the initial settings of
the transmitter.
Define Measurement Variable (
P01 Device Mode)
Surface, distance, volume and mass quantities can be selected in this menu. Each of the variables listed
in this section will change the output current in proportion to their changes.
Define Max. Liquid Level to Reference Point, with Current Output of 20 mA (
P02 20 mA Setup
)
To determine the maximum liquid level at which the transmitter generates 20 mA current at the output
and other levels, a point must first be considered as a reference level; Normally, the reference level is the
same as the minimum liquid level that is proportional to the 4 mA output current, so that calculations of
other levels are easier.
However, the user can select any other level as a reference level, depending on the circumstances and at
will; After determining the reference level, it must be determined how much higher or lower than the
reference level is the maximum expected level for the liquid at which the transmitter has a current output
of 20 mA; If it is higher, the value of the distance should be positive and if it is lower, this value should be
entered with a negative number in this setting.
Figure 18 - Determining the level parameters of a sample tank
For example, in the figure above, because the point that is considered as the maximum point of the liquid
level, is L unit above the reference level (tank floor), the parameter "P02 20mA Setup" must be set to + L.
Define Display Mode (
P03 Display Mode
)
Level-distance, wave curve, echo and several other display modes are provided by the equipment; by
selecting any of the display modes, the information will be shown in that mode and will remain in the same
mode until the display mode is reset.
One of the options that the equipment provides to the user is to select a custom variable to display that
the user can use a HART modem to specify the name, up and down range and the unit of quantity, which
in this case is appropriate to liquid level changes, changes to that variable will be displayed.
Probe Surface
Max. Liquid Level
Zero Point
Min. Liquid Level
L
