diff --git a/main.cpp b/main.cpp
index b303732..bbda937 100644
--- a/main.cpp
+++ b/main.cpp
@@ -86,7 +86,7 @@ static void dsp_thread() {
             // FIXME: net::write seems unimplemented as of libstdc++ 13
             float freq_error = freq_peak_local - freq_setpoint;
             tec_socket.write_some(net::buffer(std::format(":SOUR2:VOLT {:.3f}\n",
-                std::min(tec_bias+tec_p*freq_error, 0.0f))));
+                std::max(tec_bias+tec_p*freq_error, 0.0f))));
             last_tec += 100ms;
         }