Figure 5. Spring terminal pinout
Thermocouple connec ons
A thermocouple consists of two dissimilar metals that are joined together at one end. When the junc on of the
metals is heated or cooled, a voltage is produced that correlates to temperature.
The RedLab WebDAQ 316 supports type J, K, S, R, B, E, T, N thermocouples (TC), and provides overvoltage
protec on between any two inputs. A typical thermocouple connec on is shown in Figure 6.
Figure 6. Typical thermocouple connec on
Connect the shield to a common mode voltage reference on the thermocouple. A valid reference is voltage
within ±1.2 V of all the connected thermocouples.
Minimizing thermal gradients
Changes in the ambient air temperature near the thermocouple connectors or a thermocouple wire conduc ng
heat directly to terminal junc ons can cause thermal gradients. Observe the following guidelines to minimize
thermal gradients and improve system accuracy:
Use small-gauge thermocouple wire. Smaller wire transfers less heat to or from the terminal junc on.
Run thermocouple wiring together near the spring terminal connector to maintain a consistent
temperature.
Avoid running thermocouple wires near hot or cold objects.
Minimize adjacent heat sources and air flow across the terminals.
Keep the ambient temperature as stable as possible.
RedLab WebDAQ 316 User's Guide
page 10
