Input Configuration
There are two additional inputs, which can be set up on the SGA. One is commonly used for connecting a Lambda analog oxygen probe designed for a 0 – 21% O2 measurement. There is a second input for a thermocouple if required. The inputs must be calibrated at the low and high ends of input voltage range to ensure accurate readings. SSi suggests that this device should be calibrated on a routine basis, such as once a year or as prescribed by the user’s quality system requirements.
To perform a calibration, a certified calibrator(s) with the ability to source and read millivolts and/or thermocouples is required. The appropriate connection leads are also required. The default calibration is performed using a zero and span routine for the pre-defined input sensory type (i.e. voltage or temperature). Millivolt ranges used for thermocouple inputs are listed in the Table below.
|
Thermocouple Type |
Millivolt Range |
|
B |
0 – 20 mV |
|
C |
0 – 40 mV |
|
E |
0 – 80 mV |
|
J |
0 – 80 mV |
|
K |
0 – 80 mV |
|
N |
0 – 80 mV |
|
NNM |
N/A |
|
R |
0 – 40 mV |
|
S |
0 – 20 mV |
|
T |
0 – 20 mV |
ThermocoupleTypes and Calibration Voltage Ranges