Base component for a contactor.
A contactor is an electrically operated switch used for controlling motors
and other electrical loads.
BaseContactor handles one or two digital outputs to control the contactor, and
a digital output for the feedback.
The default configuration is on output, where the contactor is turned on when
the output is high, and off when the output is low.
When the object is configured with two outputs, normally one output is used
for On pulse, and one for Off pulse. There is also an alternative configuration
with On pulse and inverted Off output without pulse.
If a signal for contactor feedback is present, and the feedback is lost, and alarm
is generated. This applies to a configuration with one output. A configuration with
doesn't generate any alarm.
The alarm can be disabled by setting the DisableSup input of the function object.
This does not affect the Error output of the function object.
Object Graph
The Order indicator shows the status of the order output, and the Feedback
indicator the feedback from the contactor. TimeLimit displays the the timeout
for the feedback after a turn on.
The Feedback indicator is colored red in 2 seconds at feedback fault.
The figure shows a configuration with a contactor.
Supervision
If the contactor has feedback signal, the feedback is supervised. If it is
lost, or doesn't arrive in time, an alarm is sent.
Configuration
Component Configuration
- OrderFeedback The contactor an order output and feedback signal.
- OrderNoFeedback Order output and no feedback signal.
- FeedbackNoOrder Feedback signal but no order output.
- NoOrderNoFeedback Neither order nor feedback.
- TwoOrderFeedback Two pulsed order outputs for on/off, and feedback signals.
When the contactor is configured with two order outputs the following applies
- a feedback signal has to be present.
- the alarm and the error output of the function object are disabled.
- the Off order can be configured to be an off pulse, or as another rare
configuration without pulse but with inverted function.
This configuration alternative is used with pulsed on/off control, i.e. when
the contactor should remain energized if the control system is taken down,
or when several independent systems control the contactor. See example below
for more information.
Signals
Signals that should be connected to channel objects:
- Order Do
- OrderOff Do (optional)
- Feedback Di (optional)
Supervision and error handling
If the feedback doesn't arrive in time, or is lost, an alarm is sent.
The Error output of the function object should be used to reset the output
order to avoid unwanted restarts. This is the responsibility of the programmer.
Example
Example 1 One order output and error handling
The figure shows a configuration with one order output. The contactor is always
controlled from the ProviewR system.
The internal error handling of the object sets the Error output when the
contactor feedback doesn't arrive within a certain time, or is lost, and
an alarm is generated. This alarm can be disabled by the DisableSup input.
The graph shows what will happen when the contactor feedback is lost. After
the FbTimeLimit time the Error output is set, which a reset of the
order input of the function object. Otherwise there would be an unwanted
restart when the Error output is reset.
Example 2 On and Off pulse
The figure shows a configuration with two order outputs for On and Off pulse.
The electrical maneuvering of the contactor are med with pulses. This
implies that if the control system is taken down, an energized contactor
remains energized.
The Error output of the function, and the alarm generation is disabled
when two order outputs are used. In this case the error handling has to
be programmed, which can be seen in example 3 and 4 below.
The On and Off inputs should be activated with short pulses, for example from an
egde object. The On pulse to the contactor is always 1 s and the Off pulse 1.5 s.
The length is independent of the length of the in pulses to the function object.
An Off puls can not be set the first scan at system start. If an off pulse is
required at system start, you have to wait one scan before setting the Off input
of the function object.
Note in the graph, that there is no action when the feedback is lost.
Example 3 On and Off pulse with multiple control
The figure shows a configuration with two outputs for on and off pulse. The
contactor is controlled by the ProviewR system, but can also be maneuvered
manually with pushbuttons, i.e. the contactor is operated from two independent
systems. Normally you don't have any feedback supervision, as the other maneuvering
system has the possibility to operate the contactor.
If any error handling is needed in this case, this has to be programmed. Study
the code in the figure to see how this can be done.
Function in the example
- the pulse controlled Do outputs are activated by short pulses on the On and Off
inputs of the function object.
- The contactor can be operated from the control system, or from local pushbuttons.
- The contactor feedback is supervised when turned on by the Plc.
- There is no supervision if the local on button has turned on the contactor.
The contactor in the aggregates BaseMotorAttr, BaseFcPPO3MotorAggr, BaseFcPPO5MotorAggr
and ABB_ACS800MotorAggr works in this way, when a contactor with two order outputs is
configured.
Example 4 On pulse and turn off without pulse
The figure shows a configuration with two order outputs and the attribute
OpNoOffPulse is set to 1. The Do Order gives an on pulse and the OrderOff
output follows the status of the On input of the function object.
The inputs dis and off, and the output err is not used in this configuration.
This configuration is used when you have to use an on pulse to the
contactor, and also a turn off of the contactor if the control system is
going down.
How the error handling can be done is showed in the example. The wait object
FbTimeOut resets the on input.
The graph shows when the contactor feedback is lost. The output of the wait
object switches to high, causing the on input of the function object to be
reset, and also the Do OrderOff.
Plc coding
For plc coding the function object BaseContactorFo is used.
Create a function object in the plc editor and connect it to the current
object with the connect function.
Simulate
For simulation of the sensor value, use the plc object BaseContactorSim.
See also
