Rev. 1.5
16
www.hartmann-electronic.com
3.3 Fans
3.3.1 Fan Speed Measurement
The CLM can measure the rotation speed of up to 6 fans simultaneously.
The standard fan speed signal is the open collector pulse output provided by many fans. If
such signal is not available, the fan current (measured at a small shunt resistor) can used and
the CML calculates the rotation speed by analyzing this current signal.
The fan rotation speed is accessible with SNMP network commands (crate.fantray.fanSpeed
OID)
Figure 3-6:
Window “Fans” in SYScontrol
3.3.2 Fan Speed Regulation
The CML provides 6 independent fan supply outputs. The output voltage is regulated by the
CML to achieve the requested rotation speed.
The nominal fan speed is changeable with the SNMP network commands
(crate.fantray.fanNominalSpeed OID)
or in SYScontrol window “Global”
An automatic fan speed regulation depending on the temperature sensors is also possible.
