imc CRONOS-PL/-SL/compact - Getting Started, Version 5 R 7 - 2018-06-28
© 2018 imc Meßsysteme GmbH
Fuses (polarity-inversion protection)
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2.10 Fuses (polarity-inversion protection)
The device supply input is equipped with maintenance-free polarity-inversion protection. No fuses or
surge protection is provided here e.g. with CRSL and CRPL. Particularly upon activation of the device, high
current peaks are to be expected. When using the device with a DC-voltage supply and custom-designed
supply cable, be sure to take this into account by providing adequate cable cross-section.
With CRC the device supply input is equipped with a fuse against surge protection (refer technical specs:
CRC). The exchange of the fuses has to be done concerning chapter: "changement of the fuses CRC (side
panel)".
Devices with AC supply are equipped with a protection (refer technical specs: CRC).
The supply voltage for external sensors wired out from the voltage channels is equipped with
maintenance-free electronic fuses (current-limiters).
The incremental counter channels provide a supply voltage for external sensors, which is not protected
and should be provided with an external fuse in order to be used!
2.11 UPS
Devices with DC supply input are equipped with an uninterruptible power supply (UPS). This allows for a
continuous operation unaffected by temporary short-term outage of the main power supply. This type of
operation is particularly useful for operation in a vehicle, permanently attached to starter lock and main
power switch and thus not requiring manual control. Activation of UPS buffering is indicated by the
power control LED (PWR) changing from green to yellow. With many imc measurement devices, active
UPS buffering is additionally indicated by an acoustic buzzer signal.
The UPS provides backup in case of power outage and monitors its duration. If the power outage is
continuous and if it exceeds the specific device’s "buffer time constant", the device initiates an automatic
shutdown sequence, which equals manual shutdown procedure: Any current active measurement is
automatically stopped, data storage on flash card or internal harddisk is completed by securely closing all
data files, and finally the device is actually switched off. This entire process may take a couple of seconds.
Thus, a typical application of this configuration is in vehicles, where the power supply is coupled to the
ignition. A buffer is thus provided against short-term interruptions. And on the other hand, deep
discharge of the buffer battery is avoided in cases where the measurement system is not deactivated
when the vehicle is turned off.
If the power failure is not continuous but only temporary, the timer that monitors blackout duration is
reset every time the main supply has returned to valid levels. The buffer time constant is a variable
device parameter that can be configured according to system size and battery capacity. It can usually be
written into the device under software control and is preconfigured to reasonable default values upon
delivery (see description in the software manual).
Reference
Please find the technical specs (buffer duration) in the manual or in the data sheet.
