i have a "double Motor module" (6sl3120-2TE21-8AA3). and i have a trouble, when i push on, red led (RDY light) is on, and module dont working

dear all,

i have a "double Motor module" (6sl3120-2TE21-8AA3). and i have a trouble, when i push on, red led (RDY light) is on, and module dont working.

i alse have a "double Motor module" (6sl3126-2te21-8AA3). when i supply 24VDC, red led (RDY light) is on. and it dont working.

i dont know those error related to module or my system, my system had run well for 3 months with 2 module before it have a trouble. i see on Manual S120, it said that led is red Continuously because At least one fault is present in this component.

can you show me its reason why red led is on.

thank in advance.