OM-WEB Series User's Guide
Specifications
34
Semiconductor sensor measurement accuracy
Table 5. Semiconductor sensor accuracy specifications
Sensor type
Temperature range (°C)
Maximum accuracy error
LM35, TMP35 or
equivalent
–40 °C to 150 °C
±0.50 °C
Note 6:
Error shown does not include errors of the sensor itself. These specifications are for one year while
operation of the OM-WEB-TEMP is between 15 °C and 35 °C. Contact your sensor supplier for details
on the actual sensor error limitations.
RTD measurement accuracy
Table 6. RTD measurement accuracy specifications
RTD
Sensor
temperature
Accuracy error (°C)
max
Accuracy error (°C)
typ
Tempco (°C/°C)
PT100, DIN, US or
ITS-90
–200 °C
2.913
2.784
0.001
–150 °C
1.201
1.070
0.001
–100 °C
0.482
0.349
0.001
0 °C
0.261
0.124
0.001
100 °C
0.269
0.127
0.001
300 °C
0.287
0.136
0.001
600 °C
0.318
0.150
0.001
Note 7:
Error shown does not include errors of the sensor itself. The sensor linearization is performed using a
Callendar-Van Dusen linearization algorithm. These specs are for one year while operation of the OM-
WEB-TEMP is between 15 °C and 35 °C. The accuracy and tempco specifications
include
the
accuracy of the Callendar-Van Dusen linearization algorithm. The specification does not include lead
resistance errors for 2-wire RTD connections. Contact your sensor supplier for details on the actual
sensor error limitations.
Note 8:
Resistance values greater than 660 Ω cannot be measured by the OM-WEB-TEMP in the RTD mode.
The 660 Ω resistance limit includes the total resistance across the current excitation (±Ix) pins, which
is the sum of the RTD resistance and the lead resistances.
Note 9:
For accurate three-wire compensation, the individual lead resistances connected to the ±Ix pins must be
of equal ohmic value. To ensure this, use connection leads of equal lengths.
