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®
ThermoView
TV30 Series
Users Manual, Rev. 1.0, May 2023
9 Maintenance
Our sales representatives and customer service staff are always at your disposal for questions regarding
applications, calibration, repair, and solutions to specific problems. Please contact your local sales representative
if you need assistance. In many cases, problems can be solved over the telephone. If you need to return equipment
for servicing, calibration or repair, please contact our Service Department before shipping. Phone numbers are
listed at the beginning of this document.
9.1 Fail-Safe Operation
In cooperation with I/O capabilities , the camera provides a fail-safe system. That system is designed to alert the
operator and provide a safe output in case of certain system failures.
The following system failures cause a fail-safe operation:
Power supply is lost or out of range
Internal temperature of the camera is out of range
Firmware has crashed
When an error or failure does occur, all internal outputs of the camera adjust to a tristate level. A tristate level
means that the output signal is neither logically 0 nor 1, but high impedance. Such a signal makes the camera
behave as if its output is temporarily disconnected from the surrounding circuits.
W
For automatic fail-safe monitoring, the user can make the following implementation:
Electrically consider an Open-Drain implementation for the internal digital outputs of the camera, see
section 5.7.3
Define a measurement condition that is always false and assign one internal digital output to that
measurement condition, see section 7.2.2
Note: The considered output must be exclusive, that means no other condition can switch this output.
Make sure that the considered output is non-inverted. Switch the output type to <Open Drain>, see section
7.4.1
The considered output is now always on low signal as long as no fail-safe occurs. In case of a fail-safe
the output goes to tri-state and the Open Drain implementation provides a high signal. This behavior can
be permanently monitored by an external control system to indicate a fail-safe condition.
88
Warning
The Fail-Safe circuit should never be relied on exclusively to protect critical processes. Other
safety devices should also be used to supplement this function!
Digital
Outputs, page 30
<I/O>
<Internal>, page 48.
<Camera>
<Conditions>, page 38.
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