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Using Intelligent Output Terminals Section 4-6
4-6-3 Internal Relay Output
The inverter has an internal relay output
with normally open and normally closed
contacts (Type 1 form C). The output sig-
nal that controls the relay is configurable;
the Alarm Signal is the default setting.
Thus, the terminals are labeled [AL0],
[AL1], [AL2], as shown to the right. How-
ever, you can assign any one of the nine
intelligent outputs to the relay. For wiring
purposes, the general terminal functions
are:
• [AL0] – Common contact
• [AL1] – Normally open contact
• [AL2] – Normally closed contact
The relay itself can be configured as "normally open or closed." Parameter
C036, Alarm Relay Active State, is the setting. This setting determines
whether or not the relay coil is energized when its output signal is OFF:
•
C036=00 – "Normally open" (relay coil is de-energized when output signal
is OFF)
•
C036=01 – "Normally closed" (relay coil is energized when the output sig-
nal is OFF)
Since the relay already has normally
open [AL1] and normally closed [AL2]
contacts, the purpose of the ability to
invert the relay coil's active state may not
be obvious. It allows you to determine
whether or not an inverter power loss
causes the relay to change state. The
default relay configuration is the Alarm
Signal (
C026=05), as shown to the right.
And,
C036=01 sets the relay to "normally
closed" (relay coil normally energized).
The reason for this is that a typical sys-
tem design will require an inverter power
loss to assert an alarm signal to external
devices.
The relay can be used for other intelli-
gent output signals, such as the Run
Signal (set
C026=00). For these remain-
ing output signal types, the relay coil typ-
ically must NOT change state upon
inverter power loss (set
C036=00). The
figure to the right shows the relay set-
tings for the Run Signal output.
If you assign the relay an output signal
other than the Alarm Signal, the inverter
can still have an Alarm Signal output. In
this case, you can assign it to terminal
[11] , providing an open collector output.
AL1AL0 AL2
Inverter logic
circuit board
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