DCS SERIES OPERATION MANUAL
SECTION 8: MASTER/SLAVE OPERATION
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2018 by Adaptive Power Systems, Inc. (APS) • All Rights Reserved • No reproduction without written authorization from APS.
6RL Series Regenerative DC Load Operation Manual
Page 194 of 204
transferred 1:1 to the slaves. During operation, a slave may causes an alarm or event
rather than the master, due to imbalanced current or slightly faster response time.
Note: In order to easily restore all these settings values to what they were before activating
M/S operation, it is recommended to make use of the user profiles (See section 6.4.3.4,
“Profiles Menu”, on page 69).
If one or more slaves reports a unit alarm, it will be displayed on the master and must
be acknowledged there so that the slave(s) can continue their operation. Since an alarm
causes the DC Input to be switched off and can only reinstate automatically after PF or
OT alarms, the operator or remote control software will have to turn the output back on
again.
Loss of connection to any slave will result in shutdown of all DC Inputs, as a safety
measure. The master will report this condition on its display with a pop-up “Master-
slave security mode”. Then the M/S system has to be re-initialized, either with or
without re-establishing connection to the disconnected unit(s) before.
All units, even the slaves, can be externally shut down on the DC Inputs using the pin
REM-SB of the analog interface. This can be used as an emergency off, where usually a
contact (maker or breaker) is wired to this pin on all units in parallel.
8.2.6
Alarms and other problem situations
Master-slave operation, due to the connection of multiple units and their interaction, can cause
additional problem situations, which do not occur when operating individual units. For such
occurrences the following regulations have been defined:
If the DC part of one or more slave units is switched off due to defect, overheating etc.,
the whole MS system shuts down the power output and human interaction is required.
If one or more slave units are cut from AC supply (power switch, blackout, supply under
voltage) and come back later, they’re not automatically initialized and included again in
the MS system. Then the init has to be repeated.
If the DC Input of the master unit is switched off due to a defect or overheating, then
the total master-slave system cannot provide output power and the DC Inputs of all
slaves are automatically switched off, too
If the master unit is cut from AC supply (power switch, blackout) and comes back later,
the unit will automatically initialize the MS system again, finding and integrating all
active slaves. In this case, MS can be restored automatically.
If accidently multiple or no units are defined as master the master-slave system cannot
be initialized
In situations where one or multiple units generate a unit alarm like OVP etc. following applies:
Any alarm of a slave is indicated on the slave’s display and on the master’s display.
If multiple alarms happen simultaneously, the master only indicates the most recent
one. In this case, the particular alarms can be read from the slave units displays or via
digital interface during remote control or remote supervision.
All units in the MS system supervise their own values regarding overvoltage, overcurrent
and overpower and in case of alarm they report the alarm to the master. In situations
where the current is probably not balanced between the units, it can occur that one unit
generates an OCP alarm though the global OCP limit of the MS system was not reached.
The same can occur with the OPP alarm.
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