National Instruments SCC-CTR01, User Manual And Specifications

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© National Instruments Corporation 13 NI SCC-CTR01 User Guide and Specifications
Theory of Operation
Input (Source and Gate)
Optical Isolation
The gate and source inputs are isolated from each other and from the
NI SCC-CTR01 internal power and ground signals. The isolation barrier
protects the NI SCC-CTR01 and other equipment from voltages up to
60 VDC. Common-mode voltages higher than 60 VDC can damage the
NI SCC-CTR01 and other equipment. The isolation allows for increased
input ranges. The input signal can be varied between 0 VDC and 48 VDC
between the + and – terminals. The isolation also protects against ground
loops.
Reverse and Over-voltage Protection
A diode placed between the + and – input terminals provides reverse
voltage protection to the NI SCC-CTR01 and other equipment. In addition,
the NI SCC-CTR01 is equipped with overvoltage protection and can
handle continuous voltages, between the + and – input terminals, up to
±60 VDC.
Frequencies of Operation
Based on the application, the NI SCC-CTR01 may operate at higher than
the maximum frequency specified in the
Specifications section. Table 1
lists the typical NI SCC-CTR01 input channel operating rates.
Table 1. NI SCC-CTR01 Typical Input Tasks Maximum Rates
Operating
Voltage
Counting
Edges
Pulse Width
Measurement,
Semi-Period
Measurement
Period
Measurement,
Frequency
Measurement
Position
Measurement
5 V 1 MHz 0.6 µs 1 MHz 1 MHz
24 V 800 kHz 1 µs 800 kHz 800 kHz
48 V 400 kHz 1 µs 400 kHz 400 kHz
Notes : Typical at 25 °C, 1 meter cable connected to DAQ device.
Measurement accuracy can be improved by adjusting the LOW to HIGH and HIGH to LOW switching times in the software.
Refer to the
Theory of Operation section for more information.