CT-600/CT-1000 User’s Manual
14
2.3
Secondary-side Signals
The signals on the “secondary” side of the CT-600 and CT-1000 current
transducers are found on pins #1, 2, 3, 6, 7 and 8 (please note that not all of them are
present on all versions) of the DE-9 connector.
2.3.1
Power Supply
Supply voltages for the CT-600 and CT-1000 have to be fed to pin #9 (+15V)
and to pin #5 (-15V) of the D-sub 9-pin connector; both these voltages are referred to
pin #4 (GND).
Maximum current that can be drawn from each one of these supply voltages is
of 450 mA for CT-600 and 550mA for CT-1000 (a maximum of 50 mA for supplying
the internal electronics circuits and a maximum of 400 mA for CT-600 or 500 mA for
CT-1000 for the secondary current).
2.3.2
Secondary Current (current versions only)
On the “standard” current output versions the secondary current output
I
S
,
scaled by its current transformation ratio is fed to pin #6. Current return pins are
respectively found on pin #1 and on pin #7.
Maximum secondary current depends over the full-scale range and the current
transformation ratio of the sensor. For example for a CT-1000 the full-scale range is
±1000 A and its transformation ratio is 1:2000, thus its maximum secondary current is
rated at ±500 mA. An external shunt resistor, which can be placed close to the user’s
desired measuring circuit (to avoid the noise pick-up), is needed in order to convert the
current signal to a voltage.
The voltage output pins (V
O
and V
O
RET) cannot be found on standard current
output versions.
2.3.3
Voltage Output (“V” versions only)
A buffered output voltage signal is present on the voltage output versions of the
transducers in order to allow easier connection of the DCCT to an external circuit or an
Analog to Digital converter (ADC).
The full-scale output bipolar signal
V
O
(pin #2 for “V”-version) is referred to
V
O
RET
(pin #7) and the behavior is as follows:
•
+10V output if the primary current is equal to positive full scale of the sensor;
•
–10V output if the primary current is equal to negative full scale of the sensor.
