Sensor with concurrent autosensing of output mode and manual selection

摘要

A switching sensor may automatically configure itself to a sinking or a sourcing mode by monitoring the voltage of its switched output to determine a loading configuration associated with each of these operating modes. The auto detection may occur not only at start up but also during operation of the sensor by monitoring the output voltage or current in coordination with knowledge about the intended state of the output by the sensor. A manual selection of the operating mode and override of the autodetect feature may be provided for cases when multiple sensors are connected in parallel.

主权项

1. An electrical sensor providing a switched electrical output, the electrical sensor comprising:
a sensor element sensing a physical condition to produce a sensor signal; a first solid-state switching device connected between a source of power and a sensor output to source current at the sensor output when the first solid-state switching device is activated; a second solid-state switching device connected between ground and the sensor output to sink current at the sensor output when the second solid-state switching device is activated; an autodetection circuit operable to:
produce a switched signal based on the sensor signal,receive a mode signal having a first state and a second state, wherein the first state corresponds to the sensor output sourcing current and the second state corresponds to the sensor output sinking current,route the switched signal to the first solid-state switching device when the mode signal is in the first state and to the second solid-state switching device when the mode signal is in the second state,when the sensor element produces the sensor signal, monitor the sensor output to identify a presence of one of a sinking load connected between the sensor output and a source of power and a sourcing load connected between the sensor output and ground,when the presence of the sourcing load is identified as the sensor element produces the sensor signal, set the mode signal to the first state, andwhen the presence of the sinking load is identified as the sensor element produces the sensor signal, set the mode signal to the second state.