Indicator Lights - Grundfos IO 401 Montage- Und Betriebsanleitung

4. Indicator lights

Digital inputs 1 to 5:
The indicator light is yellow when the input is active.
Relay output 8:
The indicator light is yellow when the output is active.
Inputs for PTC sensor 6 and 7:
The indicator light is green when
• the input is used with PTC sensor (< 500 Ω).
• the input is used with thermal switch (closed).
The indicator light is red when
• the input is used with PTC sensor (MΩ).
• the input is used with thermal switch (open).
Status (S):
The indicator light is green when the IO 401 module is
active and OK.
The indicator light is red if the IO 401 module does not func-
tion correctly.
Note: The indicator light is red until the program has been
loaded into the CU 401.
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