Index: fact/BIASctrl/History.txt
===================================================================
--- fact/BIASctrl/History.txt	(revision 10096)
+++ fact/BIASctrl/History.txt	(revision 10107)
@@ -6,2 +6,3 @@
 7/12/2010	Added dynamic mode
 6/1/2011	RampVoltages() had infinite loop if crate communication stopped
+19/1/2011	'hv' command crashed when no bias board was present
Index: fact/BIASctrl/User.cc
===================================================================
--- fact/BIASctrl/User.cc	(revision 10096)
+++ fact/BIASctrl/User.cc	(revision 10107)
@@ -204,6 +204,10 @@
 	}
 
+
 	// Loop over given crates and channels
 	for (int i=Crt.Min; i<=Crt.Max; i++) for (int j=Chan.Min; j<=Chan.Max; j++) {
+	  // Check that indices are in legal range
+	  if (i<0 || i>=(int) Crates.size() || j<0 || j >=NUM_CHANNELS) continue;
+ 
 	  // Voltage change (number starts with + oder -) ignored if current DAC value is zero
 	  if (isdigit(Parameter[n+1][0])==0 && Crates[i]->GetDAC(j) == 0) continue;