MX28B 21
6. SETUP, ADJUSTMENTS, AND OPERATION6.1 User Interface
The MX28B control unit provides a user interface designed with a hierarchical menu that
can be viewed on the 32-character display by “navigating” with the “ï” (left), “ð” (right), “ñ”
(up), and “ò” (down) arrow keys located on the front panel. The selected item on the
display is identified by the cursor cycling beneath its characters.
The “M” (modify) key and the arrow keys are used to set parameters and text to customize
the system operation for a specific application. Items that can be modified have "m+" in the
upper right corner of the display. (If a security level higher than the one presently set is
required to modify the parameter, "s+" is displayed instead of “m+”.) Status, alarms, and
information screens have "+" in the upper right corner of the display (or “#” in the case of
rectifier information screens) and can not be modified. When ac power is initially applied,
there is a 60-second period during which no alarms are reported.
Pressing the "M" key on the front panel will change the "m+" to "M+", indicating that the
parameter can now be changed using the arrow keys. Some parameters can be changed
to other predefined selections by pressing the up or down arrow keys to display an
alternative selection. These parameters can be recognized after the “M” key is pressed by
the cursor cycling beneath the characters of the selection. For other parameters, such as
text and most numeric values, after the “M” key is pressed the cursor will be displayed
under an individual character. The right or left arrow key is used to position the cursor
below the character to be changed and the up or down arrow key is used to "spin" the digit
or letter to the desired value. When the desired changes have been made to an individual
parameter screen, the “M” key is pressed again; the “M+” changes back to “m+” and the
new entry is stored in memory.
If the user plans to make any changes to system parameters, the first item that should be
verified or entered is the appropriate password for the security level required for the
parameters to be modified. Security level 2 enables modification of all variable system
parameters, level 1 permits modification of some parameters; no security is required for
viewing status items. The security level password is entered through the “PIN” screen. If
no front panel keys are pressed for 60 minutes, the active password reverts to “0000” and
“ADVANCE” begins to move about the display. Pressing any key returns the display to
normal; the password must be re-entered if system parameters require changes.
Eleven LEDs are provided on the front panel of the control unit to indicate system status.
Three LEDs grouped together vertically provide overall system status; they are “MAJOR”,
“MINOR”, and “NORMAL”, indicating the presence of a major alarm, a minor alarm, or
normal operation. The other eight LEDs correspond to the active state of each of the alarm
output relays and are labeled “ALM1”···“ALM6”, “MIN”, and “MAJ”.
6.2 External Alarm Inputs
The four external alarm inputs (also referred to as “Input Relay Alarms”) can be assigned a
priority and routed or “mapped” to alarm output relays. Available assignments are “Ignore”,
“Major”, “Minor”, and “Relay 1” ··· “Relay 6”. Screens for making the assignments are
located at [SYSTEM/IN-RLY/RLY-MAP]. A user defined name or “alias” may also be
assigned to each of these input alarms. Screens for making these assignments are located
at [SYSTEM/IN-RLY/ALIAS]. For information on wiring connections to these inputs refer to
Section 5.6.1.