Software
4
4-14
4.4 Power Line Rejection

The OM-DAQ-USB-2401 Series can take readings while making use of 50/60Hz

line cycle rejection. While in the line cycle rejection mode, the maximum sample

rate is as follows:

• 50 Hz rejection: Scan Rate (SR) Range: 0.153Hz < SR <= 1Hz

• 60 Hz rejection: Scan Rate (SR) Range: 1Hz < SR <= 1.667Hz

Figure 4-25. OM-DAQ-USB-2400 Block Diagram

4.5 Optical Isolation

Your DAQ unit is optically isolated from its host PC by up to 500 Vdc. This

means that an inadvertent application of such voltage to the DAQ unit will not

affect the PC. In addition to isolation, the device maintains all sensitive

acquisition-related circuitry external to the PC. This physical isolation of

circuitry from the PC results in less noise and more accurate measurements.

4.6 A/D Conversion

OM-DAQ-USB-2401 uses an extremely low-noise, 24-bit analog-to-digital (A/D)

converters. They provide complete high-resolution measurement solutions for

the most demanding applications.

Power LED
Power Jack
Power Supply
Local Power
Digital Isolators
Isolation
Barrier
Isolated
Power Supply
USB
Controller
Gain =
x2, 1/8
Gain =
x2, 1/8
Gain =
x1,2,4,8,16
32,64
24–Bit
A/D
PGA
MUX
PGIA
PGIA
SE/
DI
SE/
DI
MUX
MUX
CJC
CJC
CJC
1MΩ
1MΩ
1MΩ
1MΩ
+12v
+12v
CJC
Activity LED
USB
Jack
4
Analog Inputs
4
Analog Inputs
+12v output
Excitation voltage
+12v output
Excitation voltage
4
Analog Inputs
4
Analog Inputs
+12v output
Excitation voltage
+12v output
Excitation voltage
MCU
32Bit
OMB-DAQ-USB-2401 Series Block Diagram