Fisher publishes safety integrity level (SIL) data in their manuals. If your plant requires SIL compliance, you must follow the installation and proof-test procedures from the official PDF.
Check for air leaks in the tubing and ensure the feedback linkage is tight and moving freely without "play". Fisher 3560 Valve Positioner Manual Pdf
Introduce the lower limit of the input signal (e.g., 3 psig). Fisher publishes safety integrity level (SIL) data in