diff --git a/secop_psi/ips_mercury.py b/secop_psi/ips_mercury.py
index 29c233d..d806bb0 100644
--- a/secop_psi/ips_mercury.py
+++ b/secop_psi/ips_mercury.py
@@ -56,9 +56,12 @@ class SimpleField0(MercuryChannel, SimpleMagfield):
     def read_action(self):
         return self.query('PSU:ACTN', hold_rtoz_rtos_clmp)
 
-    def write_action(self, value):
+    def unlocked_write_action(self, value):
         return self.change('PSU:ACTN', value, hold_rtoz_rtos_clmp)
 
+    def write_action(self, value):
+        return self.unlocked_write_action(value)
+
     def read_atob(self):
         return self.query('PSU:ATOB')
 
@@ -99,7 +102,7 @@ class SimpleField0(MercuryChannel, SimpleMagfield):
         return super().final_status(*args, **kwds)
 
     def on_restart(self, state):
-        self.write_action('hold')
+        self.unlocked_write_action(Action.hold)
         return super().on_restart(state)