Index: /trunk/FACT++/src/biasctrl.cc
===================================================================
--- /trunk/FACT++/src/biasctrl.cc	(revision 11957)
+++ /trunk/FACT++/src/biasctrl.cc	(revision 11958)
@@ -256,5 +256,8 @@
             }
 
-            fCurrent[id]    = status ? -ddd : ddd;
+            // There is no -0 therefore we make a trick and replace it by -1.
+            // This is not harmfull, because typical zero currents are in the
+            // order of one to three bits anyway and they are never stable.
+            fCurrent[id]    = status ? -(ddd==0?1:ddd) : ddd;
             fPresent[board] = true;
         }