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OM-USB-TC-AI User's Guide
Specifications
18
Parameter
Conditions
Specification
Common mode rejection ratio
T0x
to
T3x, f
IN
= 60 Hz
100 dB
V0x
to
V3x, f
IN
= 60 Hz, all
input ranges
83 dB
ADC resolution
24 bits
ADC No missing codes
24 bits
Input coupling
DC
Warm-up time
30 minutes min
Open thermocouple detect
T0x to T3x
Automatically enabled when the channel pair is
configured for thermocouple sensor.
The max open detection time is 3 seconds.
CJC sensor accuracy
T0x to T3x
, 15 °C to 35 °C
±0.25 °C typ,±0.5 °C max
T0x to T3x
, 0°C to 70 °C
–1.0 to +0.75 °C max
Channel configurations
Table 2. Channel configuration specifications
Channel
Category
Conditions
Specification
T0x to T3x
Disabled
All temperature input channels are disconnected from screw
terminals and internally connected to GND.
See Note 4
T0x to T3x
Thermocouple
Note 1
4 differential channels
V0x to V3x
Disabled
All voltage input channels are disconnected from screw
terminals and internally connected to GND.
See Note 4
V0x to V3x
Differential
Note 2
4 differential channels
V0x to V3x
Single-ended
4 single-ended
channels
Note 1:
Internally, the OM-USB-TC-AI has four, dual-channel, fully differential A/Ds providing a total of
eight input channels.
Note 2:
When connecting differential inputs to floating input sources, you must provide a DC return path from
each differential input to ground. To do this, connect a resistor from each of the differential inputs to
GND. A value of approximately 1Meg ohm can be used for most applications.
Note 3:
Channel configuration information is stored in the EEPROM of the isolated microcontroller by the
firmware whenever any item is modified. Modification is performed by commands issued over USB
from an external application, and the configuration is made non-volatile through the use of the
EEPROM.
Note 4:
The factory default configuration is
Disabled
. The Disabled mode will disconnect the temperature and
voltage inputs from the terminal blocks and internally connect ground (GND) to all of the A/D inputs.
Compatible sensors: T0x toT3x
Table 3. Compatible sensor type specifications
Parameter
Conditions (°C)
Thermocouple
J: –210 to 1200
K: –270 to 1372
R: –50 to 1768
S: –50 to 1768
T: –270 to 400
N: –270 to 1300
E: –270 to 1000
B: 0 to 1820
Содержание OM-USB-TC-AI
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