diff --git a/pid/pidloop.hpp b/pid/pidloop.hpp
index 0a143e7..70e0415 100644
--- a/pid/pidloop.hpp
+++ b/pid/pidloop.hpp
@@ -19,8 +19,8 @@
  * @param[in] first - boolean to denote if initialization needs to be run.
  * @param[in] cycleCnt - loop timer counter.
  */
-void pidControlLoop(std::shared_ptr<ZoneInterface> zone,
-                    std::shared_ptr<boost::asio::steady_timer> timer,
+void pidControlLoop(const std::shared_ptr<ZoneInterface>& zone,
+                    const std::shared_ptr<boost::asio::steady_timer>& timer,
                     const bool* isCanceling, bool first = true,
                     uint64_t cycleCnt = 0);