IMR01M01-E16
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7.10 Current Limiter Function
This is the function of limiting a measured current value to a value not exceeding the preset current limit value.
A current value is measured for each constant cycle and then the maximum phase angle not exceeding the Current limit value is
computed from the above current value thus measured. If the phase angle at that current output is larger than the maximum
phase angle computed, the current is output at the maximum phase angle to restrict that current.
The maximum phase angle is computed during a time period of 0.1 seconds from the start of load operation, and the Current
limit function is activated after the maximum phase angle is computed.
If a load through which large rush current flows is used, the Current limit function cannot restrict the above
current. In this case, use the Current limit function together with the Soft-start function.
Even at a Soft-start time of 0.0 seconds, the Soft-start function is activated in order to compute the maximum phase
angle during a time period of 0.1 seconds from the start of load operation.
If a current value exceeds “Current limit value + Differential gap (0.5 A or 1 A)
*” due to voltage variations or load
resistance changes while the Current limit function is being activated, the maximum phase angle is immediately
re-computed to restrict it within a cycle of 2.5 from the time when it exceeds “Current limit value + Differential gap.”
* Differential gap 0.5 A: 20 A, 30 A types
Differential gap 1 A: 45 A, 60 A, 80 A and 100 A types
If a Current limit value is set to its maximum value, the Current limit function is deactivated.
The Current limiter function cannot be used when Zero-cross control is selected.
7.11 Set Data Lock Function
It is possible to prohibit the key operation to prevent an operation error. Validate Set data lock function to lock the UP key.
The following parameters are available for Set data lock function.
• Control method (C) • Heater break alarm type (n)
• Soft-start time (U) • Alarm output selection (T)
• Soft-down time (d) • Heater break alarm 2 set value setting (F)
• Internal gradient set value (G) • Heater break alarm 2 used/unused (K)
• Output limiter high (H) • Current limit value setting (Z)
• Output limiter low (L) • Alarm output state selection (c)
• Base-up set value (b) • Protection function for control of primary side of a transformer (t)
• Output mode for phase control (o) • Determination set value in case of a break on the secondary side of
• Internal manual set value (I) the transformer ( )
• Contact input action (J) • Output limiter setting in case of a break on the secondary side of
• Maximum load current set value for alarm (P) the transformer (h)
• Heater break alarm 1 set value setting (Q) • Soft-start time in case of break on the secondary side of
• Number of alarm delay times (r) the transformer (u)
For the setting method, refer to
6.2.3 Setting method of Set data lock (P. 12).
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