| 摘要 |
An improved input module is able to sense the ON and OFF states associated with an external signal, wherein that signal complies with standards denoting the ON and OFF condition thereof. The improved input module includes a fixed impedance and a parameter sensor, such as a voltage sensor, which senses at least a portion of the voltage drop across the impedance. In addition, the module includes a current limiter in series with the impedance so as to limit the current flow through the impedance when the threshold parameter has been exceeded. An additional embodiment of the input module includes a second current limiter which is able to selectively detect broken wires associated with the connection of the external signal to the input module.
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