Overcurrent/overvoltage protection

The low-voltage power supply stops supplying the DC voltage to the product components whenever it detects excessive current or abnormal voltage from the power source.

The low-voltage power supply has a protective circuit against overcurrent and overvoltage to prevent failures in the power supply circuit.

If the low-voltage power supply is not supplying DC voltage, the protective function might be running. In this case, turn the power off and unplug the power cord. Do not plug in and turn on the product until the cause is found and corrected.

In addition, the low-voltage power supply has two fuses (FU100/FU101) to protect against overcurrent. If overcurrent flows into the AC line, the fuse blows to stop AC power.

Safety

For safety, the product interrupts the power supply of +24VB by turning off the interlock switch (SW3) and +5VC by turning off the interlock switch (SW1/SW2).

The AC power is supplied to the product even when the power switch is turned off because the product uses the soft switch for turning on/off the product. Always unplug the power cord before disassembling the product.

Sleep (powersave) mode

Sleep mode conserves energy by stopping the power to several components when the product is idle. The product has three sleep modes depending on the power consumption. The DC controller supplies or converts each power supply according to the sleep mode.

●Sleep mode 1: Stops +24VA and +24VB

●Sleep mode 2: Stops +24VA, +24VB and +5VD. Converts +5VA, +5VB and +5VC into +3.2V.

●Sleep mode 3: Stops +24VA, +24VB, +5VB and +5VD. Converts +5VA and +5VC into +3.2V.

Power supply voltage detection

The product detects the power supply voltage that is connected to the product. The DC controller monitors the POWER SUPPLY VOLTAGE (PSTYP100) signal and detects power supply voltage, whether 100 V or 200 V, to control the fusing operation.

Low voltage power supply failure

The DC controller determines a low-voltage power supply failure and notifies the formatter when the low-voltage power supply does not supply +24 V.

14 Chapter 1 Theory of operation

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