|The controller does not turn on due to one of the
- The transformer trips. Power is available at the transformer primary and
there is no voltage at the secondary.
- The breaker or fuse trips. Power is available at the transformer
primary. You find 24 V at the secondary and 0 V at the
breaker or fuse.
- The transformer shorted.
- The 24 VAC powered sensor is not wired with
the same polarity as the controller.
- The RS-485 bus device is not wired with the
same polarity as the controller.
- Ensure that the polarity of ~24 V COM on the controller, auxiliary
devices, and input and output devices is the same.
- Verify that the short circuit is resolved
with an ohm-meter.
- Reset the breaker or fuse, or replace the
Note: If you replace the transformer, replace it with a model
that uses a resettable circuit breaker. A circuit
breaker makes it easier to solve wiring
- To verify the connection, complete the
- Disconnect the secondary of the 24
- Use an ohm-meter to measure between
~24 V H and G at the controller. Ensure that no
short circuit occurs.
Note: If your installation requires that
you earth ground the transformer secondary, verify
that the earth ground connection is valid and not
shared between multiple pieces of
|Analog output mode is invalid. 0 V to 10 V output
is set to 100%, but output terminals are less than 10 V.
|Load impedance is lower than 2,000 ohms.
- Ensure that the voltage control device load impedance is higher than
2,000 ohms. For more information, refer to the voltage
device manufacturer specification.
- Disconnect the connected device and verify
that the value you require is present.
|Analog mode for a configurable output is invalid.
For example, 0 V to 10 V output results in an unwanted offset of up
to 1 V.
|The COM terminal is not
- Connect the COM terminal of the configurable
output to the common of the connected end device.
- Measure the output and verify that it
matches the command.
- Disconnect the connected device and verify that the commanded value is
|The Common Reference is incorrect.