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LIMIT THRESHOLDS (LIM)
– The LIMn thresholds are internal variables whose status depends on the out-of-limits of one particular measurement set by the user (e.g. total active power
higher than 25kW) among all those measured.
– To make the setting of the thresholds easier, since the limits can span in a very wide range, each of them can be set using a base number and a multiplier
(for example: 25 x 1k = 25000).
– For each LIM, there are two thresholds (upper and lower). The upper threshold must always be set to a value higher than the lower threshold.
– The meaning of the thresholds depends on the following functions:
Min function:
the lower threshold defines the trip point, while the upper threshold is for the resetting. The LIM trips when the selected measurement is less
than the Lower threshold for the programmed delay. When the measured value becomes higher than the upper setpoint, after the delay, the LIM status is
reset.
Max function:
the upper threshold defines the trip point, while the lower threshold is for the resetting. The LIM trips when the selected measurement is more
than upper threshold for the programmed delay. When the measured value decreases below the lower setpoint, after the delay, the LIM status is reset.
Max+Min function:
both thresholds are for tripping. When the measured value is less than lower or more than upper setpoints, then, after the respective
delays, the LIM will trip. When the measured value returns within the limits, the LIM status will be immediately reset.
– Trip denotes either activation or de-activation of the LIM variable, depending on ‘Normal status’ setting.
– If the LIMn latch is enabled, the reset can be done only manually using the dedicated command in the commands menu.
– See set-up menu M08.
BOOLEAN LOGIC (BOO)
– It is possible to create max. 8 internal variables named BOO1..8, whose status depends on the Boolean logic combination of limit thresholds, inputs, outputs,
etc.
– The operands (INP, LIM etc) can be combined between each other with the following Boolean operators: AND, OR, EXOR, AND NOT, OR NOT, EXOR NOT.
– Every Boolean variable is the result of max 4 operands combined with 3 logic operations.
– Example: if one wants the Boolean variable BOO1 to be activated when the limits LIM1, LIM2 and LIM3 are all active or when the input INP1 is active, BOO1
must programmed as the combination of LIM2 AND LIM3 AND LIM4 OR INP1.
– It is not necessary to use all 4 operands for one Boolean variable. If for instance, one wants BOO2 to be active when INP1 or INP2 are active, then it is
possible to program BOO2 settings with the combination INP1 OR INP2, leaving the following logic operations set to --- (no operation).
– The BOOLEAN LOGIC page displays, for every variable BOO1..8, the status of the single operands that are involved in the logic operation and the final result,
that is the status of the selected Boolean variable.
REMOTE-CONTROLLED VARIABLES (REM)
– DMG900 can manage up to 8 remote-controlled variables (REM1…REM8).
– Those are variables which status can be modified by the user through the communication protocol and that can be used in combination with outputs,
Boolean logic, etc.
– Example: using a remote variable (REMx) as a source for an output (OUTx), it will be possible to freely energise or de-energise one relay through the
supervision software. This allows to use the DMG900 relays to drive lighting or similar loads.
– Another possible use of REM variables is to enable/disable other functions remotely, inserting them into a Boolean logic in AND with inputs or outputs.
ALARMS (ALA)
– The user has the possibility to define a maximum of 16 programmable alarms (ALA1…ALA16).
– For each alarm, it is possible to define the source that is the condition that generates the alarm, and the text of the message that must appear on the screen
when this condition is met.
– The condition that generates the alarm can be, for instance, the overcoming of a threshold. In this case, the source will be one of the limit thresholds LIMx.
– If instead, the alarm must be displayed depending on the status of an external digital input, then the source will be an INPx.
– With the same criteria, it is possible to also link complex conditions to an alarm, resulting from the logic combination of inputs, limits, etc. In this case, the
Boolean logic variables BOOx must be used.
– For every alarm, the user can define a free message that will appear on the alarm page.
– It is also possible to define a priority for the alarm. If it is a simple indication, then the priority can be set to low. In this case the icon that follows the
message will be the ‘info’ symbol.
– If instead, the alarm must indicate a more critical situation, then setting its priority to High, the message will be displayed with the ‘Warning’ icon, and when
the alarm becomes active, the display page will move automatically on the Alarm screen.
– When one alarm with high priority is present, it is possible to activate the buzzer with an intermittent sound, for a defined period of time or as long as the
user acknowledges it with the dedicated button on the alarm page.
– When several alarms are active at the same time, they are displayed sequentially, and their total number is shown on the status bar.
– The icon
is shown on the auxiliary window when one or more alarms are active.
– To reset one alarm that has been programmed with latch, use the dedicated command in the commands menu.
– For alarm programming and definition, refer to set-up menu M09.
