CB Watch 3 User Manual v6.3 - May 2019 Page 87 of 100
Heater temperature
Winter heating monitoring
When CB must operate in harsh winter conditions, making sure that the various drive
cabinets and control cabinets are adequately heated and maintained at the proper
temperature becomes key.
In the old days, heaters were permanently on and older monitoring systems relied on
monitoring the heater current to verify that the heating resistance was not open circuit
and that the heater was working. Nowadays, manufacturers are becoming more
environment-friendly and heaters are thermostatically controlled. This means that they
are not always on and measuring heater current no longer works or the logic becomes
quite complicated to avoid creating false alarms when the heater is simply off).
Instead of using an indirect measurement (heater current), the CBW3 prefers to monitor
the end result of keeping the correct cabinet temperature.
We are therefore interested in setting a minimum and maximum threshold for the
temperature in the cabinet. An alarm will be raised if:
• Measured value > Maximum threshold
• Measured value < Minimum threshold
HMI: Settings / Aux. temperatures
Figure 142 – Thresholds for measured temperatures
Condensation prevention monitoring
In some countries with high humidity, compensation is the key issue and users are trying
to avoid condensation forming inside the cabinet on the electronics/electrical. The
heaters are there to ensure that the cabinet is always hotter than the outside ambient
temperature.
We are therefore interested in setting a minimum and maximum threshold for the
temperature in the cabinet. An alarm will be raised if:
• Measured value (inside) – Outside Ambient temp > Delta positive value
• Measured value (inside) – Outside Ambient temp < Delta negative value
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