diff --git a/.gitignore b/.gitignore
index 1dd11ec..79c6c04 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,7 @@
 /target
 /.idea
 .DS_Store
-.env
\ No newline at end of file
+.env
+# Vendor documentation such as the ebm-papst MODBUS specification. Copyrighted, and only
+# needed locally as a reference. Use git add -f to commit one deliberately
+*.pdf