Azbil SDC35 - Page 153

5-93
Chapter 5. DETAILED DESCRIPTION OF EACH FUNCTION
Handling Precautions
• Do not allow the current to exceed the upper limit of the CT input display
range. Doing so might cause a malfunction.
• If a current exceeding the upper limit of the CT input display range is detected,
the CT input failure alarm (
AL

1

1
) is displayed. However, if the excessive
current is very large, the CT input failure alarm is not displayed.
• The CT input display range and measurement current range change according
to the number of CT turns and the number of CT power wire loops. Set for
the number of CT turns and the number of CT power wire loops suitable for
the conditions of the CT connected. The display range and the measurement
current range are calculated by the formulas shown below. (The internal
calculations of this device have an error of less than 0.1A.)
Display range lower limit (A) = 0.0
Display range upper limit (A) = Number of turns ÷ (16 × number of power
wire loops) × 1.4
Measurement current range lower limit (A) = Number of turns ÷ (2000 ×
number of power wire loops)
Measurement current range upper limit (A) = Number of turns ÷ (16 ×
number of power wire loops)
The table below shows examples of how display range and measurement
current range change according to the number of CT turns and the number of
CT power wire loops. Measurement current range is shown in parentheses.
Number of
turns
Number
of power
wire loops
100 turns 400 turns 800 turns 1600 turns 4000 turns
1 time
0.0 to 8.7A
(0.1 to 6.2A)
0.0 to 35.0A
(0.2 to 25.0A)
0.0 to 70.0A
(0.4 to 50.0A)
0.0 to 140.0A
(0.8 to
100.0A)
0.0 to 350.0A
(2.0 to
250.0A)
2 times 0.0 to 4.3A
(0.1 to 3.1A)
0.0 to 17.5A
(0.1 to 12.5A)
0.0 to 35.0A
(0.2 to 25.0A)
0.0 to 70.0A
(0.4 to 50.0A)
0.0 to 175.0A
(1.0 to
125.0A)
6 times 0.0 to 1.4A
(0.1 to 1.0A)
0.0 to 5.8A
(0.1 to 4.1A)
0.0 to 11.6A
(0.1 to 8.3A)
0.0 to 23.3A
(0.2 to 16.6A)
0.0 to 58.3A
(0.4 to 41.6A)
• If ROM version 1 of the instrument information bank (
I

d02
) is prior to version
2.04, the operation is always performed on the basis of 800 CT turns and one
CT power wire loop. The number of
CT

1
/
CT2
turns and power wire loops is
not displayed and cannot be set.
• If ROM version 1 of the instrument information bank (
I

d02
) is prior to version
2.04, the CT input failure alarm (
AL

1

1
) is not displayed.