Moxa ioLogik E2210 [145/263] F accuracy

F. Accuracy

Calibration

The ioLogik E2260 achieves accuracy in temperature measurements as follows:

1. At room temperature (25 ±3°C), accuracy should be within 0.1% FSR. The measurement range of a PT-100

sensor is -200°C to 850°C. That means that readings are accurate to within ±1.05°C. If an object's

temperature is measured at 100°C, the actual temperature should be between 98.95°C and 101.05°C. A

reading of 600°C would include temperatures between 598.95°C and 601.05°C.

2. At an ambient temperature of -10°C or 60°C, accuracy should be within 0.3% FSR. If an object's

temperature is measured at 100°C the actual temperature should be between 96.85°C and 103.15°C. A

reading of 600°C would include temperatures between 596.85°C and 603.15°C.

A calibrator, such as provided by Yokogawa or Fluke, is used for the standard signal source. These products

allow Moxa to guarantee accurate measurements to within ±0.1% of FSR. The actual error rates may differ

between products. For example, when measuring a 500°C object, one product might achieve accuracy to within

0.1°C, while another product may achieve accuracy to within 0.5°C.

Simple Verification at Your Site

Product specifications may be verified by using a qualified RTD sensor. The sensor can be placed into 0°C or

100°C water to see if the temperature readings are correct. A high precision resistor may also be used for

measurement.

Verification with RTD Sensor

When using an RTD sensor, measurement errors are introduced through the sensor itself and through the

analog-to-digital signal processing. For example, suppose that the RTD sensor introduces 0.05% error and the

AD conversion introduces 0.1% error. For water at a 100°C, the measured temperature would fall somewhere

within 100±1050*(0.1%+0.05%), or between 98.425°C and 101.575°C. The 1050 corresponds to the full

range of the PT100 RTD sensor, which is -200°C to 850°C.

Therefore, with an RTD sensor that boasts accuracy within 0.05%, the measured temperature will be accurate

to within 0.15% of FSR.

Verification with Precision Resistor

A resistor with Ohm input could be used for verification. Suppose that you use the ioLogik E2260, which is rated

at 100 Ω 1%, and select 1-310 Ω mode. The measured temperature would fall within 100±(100 × 1% + 310

Ω × 0.1%), or between 98.69 Ω and 101.31 Ω. The 310 corresponds to the full scale range of 1-310 Ω mode.