Pin assignment, display and diagnosis

Increased measurement uncertainty with signal bundling of the AGND line

In this terminal, the AGND contacts (signal return line -R) are connected in the terminal.
If the connection lines are to be reduced on the system side, one line instead of n lines can be used for all n RTD sensors at this terminal.
However, since each channel individually permanently drives its measuring current (some 100 µA, see explanations chapter "RTD measurement in EL32xx"), all n RTD currents then flow via one line, there is an n-fold increase in voltage drop there, which is also recorded by the ratiometric voltage measurement in the terminal.
The result is the same as for long lines. If RTD sensors are to be connected in this way, a system-side check and, if necessary, compensation using WireCalibration CoE 0x80n0:1B (convert voltage drop to apparent line resistance for this purpose) or UserScale 0x80n0:11/12 is recommended.
Since the line resistances are temperature-dependent and the measuring current depends on the RTD resistance, however, such a static "compensation" cannot achieve the measurement uncertainty as in operation with two lines connected short.