Revision 6 HC900 Process & Safety Controller User and Installation Manual 189
21 April 2017
General Hardware Failure
(AI=convertor not working)
The software residing on the
module does not match the module
type. This diagnostic should only
result in the factory.
The loopback test of the shift
register failed.
Bad I/O Channel Diagnostics
Individual channels on I/O modules indicate their diagnostics by 6 flashes on the Scanner and CPU; the
channel’s LED does not indicate a diagnostic. Table 32 is a list of conditions that can cause a bad channel
diagnostic.
Table 32 – Bad I/O Channel Diagnostics
Failure message
indicated on Honeywell
OI or Honeywell
HCDesigner/Utilities
function block monitor
The sensor – T/C, RTD, or mV source -- is
failing burnout checks.
Check terminal block
connections
Replace source element
Replace module.
The signal at the terminals is less than
10% below the range of the sensor.
Check the signal level being
applied to the terminals.
The signal at the terminals is more than
10% over the range of the sensor.
Check the signal level being
applied to the terminals.
When attempting to take a reading, the
ADC fails. This could result if the incoming
signal is either too large or small. It also
could result if the ADC circuit is failing. If
the problem is the ADC circuit, most likely
other channels will have the same failure.
Check the signal level being
applied to the terminals.
The board indicates that the channel is
failing to output the correct value.
Check terminal connections.
The number of configured channels in the
DO function block exceeds the number of
hardware channels on the DO card.
Reconfigure the DO function
block.
Replace DO card with correct
number of channels.
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