SIEMENS
7/72
Siemens IC 10 · 2017
Overload Relays
General data
7
✓
Available
--
Not available
Features
3RU21
3RB30/3RB31
3RB20/3RB21
3RB22/3RB23
3RB24
Benefits
Features
RESET function
✓
✓
✓
✓
✓
• Allows manual or automatic resetting of the
device
Remote RESET
function
✓
(by means of
separate
module)
✓
(only with 3RB31
and external
auxiliary voltage
24 V DC)
✓
(only with 3RB21
and external
auxiliary voltage
24 V DC)
✓
(electrically via
external button)
✓
(electrically with
button or via
IO-Link)
• Allows the remote resetting of the device
TEST function for
auxiliary contacts
✓
✓
✓
✓
✓
• Allows easy checking of the function and
wiring
TEST function for
electronics
--
✓
✓
✓
✓
• Allows checking of the electronics
Status display
✓
✓
✓
✓
✓
• Displays the current operating state
Large current
adjustment button
✓
✓
✓
✓
✓
•
Makes it easier to set the relay exactly to the
correct current value
Integrated auxiliary
contacts
(1 NO + 1 NC)
✓
✓
✓
✓
(2 ×)
--
• Allows the load to be switched off if
necessary
• Can be used to output signals
Integrated auxiliary
contacts
(1 CO and 1 NO in
series)
--
--
--
--
✓
• Enables the controlling of contactors
directly from the higher-level control system
through IO-Link
IO-Link connection
--
--
--
--
✓
• Reduction of wiring in the control cabinet
• Enables communication
Connection of
optional hand-held
device
--
--
--
--
✓
• Enables local operation
Communication capability through IO-Link
Full starter
functionality
through IO-Link
--
--
--
--
✓
•
Enables in combination with the SIRIUS 3RT
contactors the assembly of communication-
capable motor starters
(direct-on-line, reversing and star-delta
(wye-delta) starting)
Readout of
diagnostics
functions
--
--
--
--
✓
• Enables the reading out of diagnostics
information such as overload, open circuit,
ground fault, etc.
Readout of current
values
--
--
--
--
✓
• Enables the reading out of current values
and their direct processing in the
higher-level control system
Readout of all set
parameters
--
--
--
--
✓
• Enables the reading out of all set
parameters, e.g. for plant documentation
© Siemens AG 2016