diff --git a/site_ansto/instrument/config/environment/hiden_xcs.sct b/site_ansto/instrument/config/environment/hiden_xcs.sct
index 88574944..4ed65085 100644
--- a/site_ansto/instrument/config/environment/hiden_xcs.sct
+++ b/site_ansto/instrument/config/environment/hiden_xcs.sct
@@ -2,7 +2,7 @@
 # Simple driver generator for the Hiden Isochema XCS vapour delivery system
 # vim: ts=8 sts=2 sw=2 expandtab autoindent smartindent nocindent
 #
-driver hiden_xcs_gen = {
+driver hiden_xcs = {
   # driver_property douglas = clowes
   usecreatenode = false
   vendor = hiden; device = xcs; protocol = std;
@@ -19,6 +19,25 @@ driver hiden_xcs_gen = {
     type = float
     priv = user
     var temperature
+    var flow = {
+      driveable = flow
+      readable = 1
+      fetch_function = fetch_flow
+      read_function = read_flow
+      read_command = 'flow1 flow2'
+      write_function = no_op
+      lowerlimit = 0
+      upperlimit = 500
+      tolerance = 1
+      pid_function = pid_flow
+      property pid_error = 0
+      property pid_deriv = 0
+      property pid_integ = 0
+      property pid_pvalue = 0.05
+      property pid_ivalue = 0.01
+      property pid_dvalue = 0.0
+      property pid_imax = 1
+    }
     var flow1
     var flow2
     var flow3
@@ -28,11 +47,20 @@ driver hiden_xcs_gen = {
       readable = 1
       read_command = '?ALL DATA'
       read_function = read_all_data
+      write_function = no_op
       checkrange_function = chkrange_function
       value = 50
       lowerlimit = 10
       upperlimit = 90
-      tolerance = 5
+      tolerance = 1
+      pid_function = pid_humidity
+      property pid_error = 0
+      property pid_deriv = 0
+      property pid_integ = 0
+      property pid_pvalue = 0.05
+      property pid_ivalue = 0.005
+      property pid_dvalue = 0.0
+      property pid_imax = 1
     }
   }
 #
@@ -65,7 +93,7 @@ driver hiden_xcs_gen = {
     writeable = 1;
     read_function = read_digital;
     write_Function = write_digital;
-    var dout2 = {
+    var enabled = {
       read_command = '?DOUT,2';
       write_command = '!DOUT,2,';
       allowed = '0,1';
@@ -149,6 +177,70 @@ driver hiden_xcs_gen = {
 @  } else {
 @    sct geterror "Syntax error for read_all_data in: '${data}'"
 @  }
+@  if { [hpropexists [sct] target] } {
+#@    sct pid_error [expr [sct target] - ${data}]
+#@    set p_value [expr [sct pid_pvalue] * [sct pid_error]]
+#@    set d_value [expr [sct pid_dvalue] * (${data} - [sct oldval])]
+#@    sct pid_deriv [sct pid_error]
+#@    sct pid_integ [expr [sct pid_integ] + [sct pid_error]]
+#@    if { [sct pid_integ] > [sct pid_imax] } {
+#@      sct pid_integ [sct pid_imax]
+#@    }
+#@    if { [sct pid_integ] < -[sct pid_imax] } {
+#@      sct pid_integ -[sct pid_imax]
+#@    }
+#@    set i_value [expr [sct pid_ivalue] * [sct pid_integ]]
+#@    set pid [expr ${p_value} + ${i_value} + ${d_value}]
+#@    sct pid_output ${pid}
+@    set pid [pid_humidity ${tc_root} [sct target] ${data}]
+@    set path [pathname [sct]]
+@    foreach node [list analog/sp1 analog/sp2] {
+@      set pid [expr -${pid}]
+@      if { [hpropexists ${path}/${node} target] } {
+@        hset ${path}/${node} [expr [hgetpropval ${path}/${node} target] + ${pid}]
+@      } else {
+@        hset ${path}/${node} [expr [hval ${path}/${node}] + ${pid}]
+@      }
+@    }
+@  }
+  }
+  code fetch_function fetch_flow = {
+@  set data 0.0
+@  set targets 0.0
+@  set path [pathname [sct]]
+@  foreach node [list flow1 flow2] {
+@    set data [expr ${data} + [hval ${path}/${node}]]
+@  }
+@  sct result ${data}
+@  foreach node [list analog/sp1 analog/sp2] {
+@    set targets [expr ${targets} + [hval ${path}/${node}]]
+@  }
+@  sct targets ${targets}
+@  if { [hpropexists [sct] target] } {
+#@    sct pid_error [expr [sct target] - [sct result]]
+#@    set p_value [expr [sct pid_pvalue] * [sct pid_error]]
+#@    set d_value [expr [sct pid_dvalue] * ([sct result] - [sct oldval])]
+#@    sct pid_deriv [sct pid_error]
+#@    sct pid_integ [expr [sct pid_integ] + [sct pid_error]]
+#@    if { [sct pid_integ] > [sct pid_imax] } {
+#@      sct pid_integ [sct pid_imax]
+#@    }
+#@    if { [sct pid_integ] < -[sct pid_imax] } {
+#@      sct pid_integ -[sct pid_imax]
+#@    }
+#@    set i_value [expr [sct pid_ivalue] * [sct pid_integ]]
+#@    set pid [expr ${p_value} + ${i_value} + ${d_value}]
+#@    sct pid_output ${pid}
+@    set pid [pid_flow ${tc_root} [sct target] ${data}]
+@    foreach node [list analog/sp1 analog/sp2] {
+@      if { [hpropexists ${path}/${node} target] } {
+@        hset ${path}/${node} [expr [hgetpropval ${path}/${node} target] + ${pid}]
+@      } else {
+@        hset ${path}/${node} [expr [hval ${path}/${node}] + ${pid}]
+@      }
+@    }
+@  }
+@  return ${nextState}
   }
   code write_function write_digital = {
    }
@@ -163,9 +255,17 @@ driver hiden_xcs_gen = {
 @  } else {
 @    set span 500.0
 @  }
-@  set par [expr int(${base} + (4095.0 * ${par} / ${SPAN}))]
+@  set par [expr int(${base} + (4095.0 * ${par} / ${span}))]
 @  set cmd "${cmd_str}${par}"
   }
+  code write_function no_op = {
+@  if { [hpropexists [sct] driving] } {
+@    if { [hpropexists [sct] writestatus] && [sct writestatus] == "start" } {
+@      sct driving 1
+@    }
+@  }
+@  return ${nextState}
+  }
 #
 # This code is after database creation
 #