Fujitsu MAP3735FC, MAP3147FC manual Power Supply Requirements, 7 Current waveform +12 VDC

4.2 Power Supply Requirements

4.2Power Supply Requirements

(1)Allowable input voltage and current

The power supply input voltage measured at the power supply connector pin of the IDD (receiving end) must satisfy the requirement given in Subsection 2.1.3. (For other requirements, see Items (4) below.)

(2)Current waveform (reference)

Figure 4.7 shows the waveform of +12 VDC.

MAP3147FC MAP3735FC

Current (500mA/div) Time (2 sec/div) Current (500mA/div) Time (2 sec/div)

Figure 4.7 Current waveform (+12 VDC)

(3) Power on/off sequence

The order of the power on/off sequence of +5 VDC and +12 VDC, supplied to the IDD, does not matter.

(4) Sequential starting of spindle motors

After power is turned on to the IDD, a large amount of current flows in the +12 VDC line when the spindle motor rotation starts. Therefore, if more than one IDD is used, the spindle motors should be started sequentially using one of the following procedures to prevent overload of the power supply unit.

a) Issue START/STOP commands at more than 12-second intervals to start the spindle motors. For details of this command specification, refer to Fibre Channel Interface Specifications.

b) Turn on the +12 VDC power in the power supply unit at more than 12-second intervals to start the spindle motors sequentially.

C141-E163 4-7