diff --git a/include/TachSensor.hpp b/include/TachSensor.hpp
index c91e21f..af39d0c 100644
--- a/include/TachSensor.hpp
+++ b/include/TachSensor.hpp
@@ -72,7 +72,8 @@
                boost::asio::io_service& io, const std::string& fanName,
                std::vector<thresholds::Threshold>&& thresholds,
                const std::string& sensorConfiguration,
-               const std::pair<size_t, size_t>& limits);
+               const std::pair<size_t, size_t>& limits,
+               const PowerState& powerState = PowerState::on);
     ~TachSensor();
 
   private: