5504GI additional supply

Hello!

After studying the general input unit datasheet here is the questions. I'd like to check the presence of the voltage approx 15..18 VDC. So:
1. Does the GI unit require additional Vin input supply (besides c-bus supply) if I use only one measurement channel and supply voltage to it (not current or sensor)?
2. If the answer is yes then does the 18VDC voltage suitable (the same as the measured signal) or it must be VAC only? The installation instruction says it may be 24 VDC/AC input and right after that it should be 16..27 VAC to the Vin terminals.

 

Yes, the General Input Unit requires power to be connected to the 24V input terminals in order to function. If you do not connect the 24V supply on the unit it will show up in a network scan but that is all. You will not be able to program the device and it will not operate.

The supply to the unit is nominally 24V, either AC or DC. 24V is the nominal supply and the unit is supplied with a 24Vac plug pack, however any supply in the range of 16 - 27V will work.

I would not use the measured signal to supply power to the unit. When the measured signal drops too low the General Input Unit will stop working. You will not be able to tell whether the reason the General Input unit is not working is due to a fault or due to the measured signal dropping too low. Even if it does work, the General Input Unit will place a load on your measured signal and, depending upon source and cable impedance, this may affect the reading.

 

Thank you very much! All is clear now. I will install separate power supply for the GI module.