Limit Thresholds; Remote-Controlled Variables; User Alarms; Master-Slave Configuration - LOVATO ELECTRIC DCRG8 Manual Operativo

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LIMIT THRESHOLDS (LIMx)
– 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 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 one.
– The meaning of the thresholds depends on the following functions:
Min function: The lower threshold defines the trip point while the upper threshold for reset. The LIM trips when the selected measurement is less than the
lower threshold for the programmed delay. When the measured value is higher than the upper setpoint, after the set delay, the LIM status is reset.
Max function: The upper threshold defines the trip point while the lower threshold for reset. The LIM trips when the selected measurement is more than
upper threshold for the programmed delay. When the measured value is 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 the lower or more than the upper setpoint, then the LIM will trip
after the respective delays. 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 setup menu M24.
1 - Type of measurement
2 - Upper threshold
3 - Threshold delay
4 - Lower threshold
5 - Status of the limit
6 - Measurement value
7 - Function
REMOTE-CONTROLLED VARIABLES (REMX)
– DCRG8 can manage up to 16 remote-controlled variables (REM1...REM16).
– These are variables which status can be modified by the user through the communication protocol and that can be used in combination with outputs.
– 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 DCRG8 output relays to drive lighting or similar loads.
USER ALARMS (UAX)
– The user can define a maximum of 8 programmable alarms (UA1...UA8).
– For each alarm, it is possible to define:
• The source, that is the condition that generates the alarm.
• The message text, that is displayed when this condition takes place.
• The alarm properties (just like for standard alarms), that is how the alarm interacts with the control of the power factor correction board.
– 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.
– For every alarm, the user can define a free-text message that is displayed on the alarms page.
– The properties of the user alarms can be defined in the same way as the normal alarms. You can choose whether a certain alarm will disconnect the steps,
close the global alarm output, etc. See chapter Alarm properties.
– When several alarms are active at the same time, they are displayed sequentially and their total number is shown on the status bar.
– To clear an alarm programmed with latch, use the dedicated command in the commands menu.
– For alarm programming and definition, refer to setup menu M26.

MASTER-SLAVE CONFIGURATION

– The Master-Slave function is available and developed to further extend the flexibility of DCRG8 application. It allows to use the controller in high power rated
plants, for casade systems of power factor correction panels, each with their own controller and associated capacitor banks.
– This solution allows to expand the power factor correction system in a modular way whenever there is an increased power requirement in the plant.
– In this configuration, measurements are made only by the first controller (Master) which controls a maximum of 32 logic steps, that are then sent to all the
slave devices.
– The slave controllers drive their own steps as indicated by the master, while performing the "local" protections, such as panel or capacitor overtemperature,
no-voltage release, harmonic protections, etc.
– The maximum possible configuration is one master with 8 slaves.
Example 1 (Application in parallel):
A system has 8 logic steps for 400 kvar in total. The system is arranged in two panels (master and slave). Each panel has 8 steps of 25 kvar each. The logic
steps are programmed as 8 banks of 50 kvar. The first step is mapped on OUT1 both for the master and for slave 1, the same for step 2 on OUT2 for the master
and the slave 1, and so on. When step 1 is activated, the first bank both of the master board (25kvar) and of the slave 1 (25 kvar) for a total of 50kvar will result
connected. In this case, the parameter P02.07 Smallest step power must be set (on the master) at the resulting value of 50kvar.
Programming of the master:
PARAMETER VALUE
P02.07 50
P03.01.01...P03.08.01 1
P04.01.01...P04.08.01 Step 1...8
P05.01 COMx
P05.02 Master
P05.03 ON
P06.01.01...P06.08.01 Step 1...8
Programming of slave 1:
P05.02 Slave1
DESCRIPTION
50 kvar, 25 on the master and 25 on the slave for each step
All 8 logic steps are of 50kvar
Outputs OUT1...OUT8 of the master are activated by logic steps 1...8
COM port used for the link
Role of master
Enable slave 1
Outputs OUT1...OUT8 of the slave are activated by logic steps 1...8
Role as slave1
G
B