Matsusada DOEF Series, Instruction Manual

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4 Operation
46
DOEF series
Matsusada Precision
4-2 Operation for Protective Function
The unit is equipped with protective functions: overvoltage, overcurrent, and sink power. Moreover, there
are two protection systems: limit-protection and cutoff-protection. Either one can be selected.
For safety reason, the limit-protection is set to 120% of the rating when the cutoff-protection is selected.
4-2-1 Protection Types:

Overvoltage protection: Works when a voltage is equal to or greater than the set protection
value is detected.

Overcurrent protection: Works when a current is equal to or greater than the set protection
value is detected.

Sink-power protection: Works when a sink power is equal to or greater than the set
protection value is detected.
It is applied with cutoff protection, but the output is not immediately
cut off after detecting the error. The unit issues a warning for a
certain period of time, approx. five seconds, and then cuts off the
output and shifts to fault state.

Door switch (Interlock) Works when the door switch opens.

Over temperature protection Works when the internal temperature of the unit is equal to or
greater than the set temperature.
4-2-2 Protection Systems:
Limit-protection
Limits voltage or current to the set value.
The output is not turned off.
The limit value can be set to positive and negative respectively, and can be used
for overvoltage and overcurrent protection.
The response rate of it is approx. 1ms.
Cutoff-protection Cuts off the output and sets a fault state when the output voltage or current
exceeds the set value.
The response rate from the detection to the protection is approx. 400ms.
The comparison on voltage or current between the measured value and the set
value is carried out as an effective value.
4-2-3 Fault and Factors
When cutoff protection of overvoltage or overcurrent protection is activated, the unit turns off its
output and indicates protection activated. The state is called
“Fault”.
Fig, Fault state due to overcurrent
The protection indicating a fault state:

Sink power protection

Door switch protection

Over temperature protection
Fault displayed position
Blinking