diff --git a/cfg/fs_cfg.py b/cfg/fs_cfg.py
index 96af89d1..1b2fd3da 100644
--- a/cfg/fs_cfg.py
+++ b/cfg/fs_cfg.py
@@ -7,6 +7,7 @@ Mod('T',
     'frappy_psi.furnace.PI2',
     'controlled Temperature on sample (2nd loop)',
     value = Param(unit='degC'),
+    meaning = ['temperature', 30],
     input_module = 'T_sam',
     output_module = 'T_reg',
     relais = 'relais',
@@ -38,7 +39,7 @@ Mod('T_reg',
 #   )
 
 Mod('T_htr',
-    'frappy_psi.ionopimax.CurrentInput',
+    'frappy_psi.furnace.PRtransmitter',
     'heater temperature',
     addr = 'ai4',
     valuerange = (0, 1372),
@@ -47,7 +48,7 @@ Mod('T_htr',
 
 
 Mod('T_sam',
-    'frappy_psi.ionopimax.CurrentInput',
+    'frappy_psi.furnace.PRtransmitter',
     'sample temperature',
     addr = 'ai3',
     valuerange = (0, 1372),
@@ -56,7 +57,7 @@ Mod('T_sam',
    )
 
 Mod('T_extra',
-    'frappy_psi.ionopimax.CurrentInput',
+    'frappy_psi.furnace.PRtransmitter',
     'extra temperature',
     addr = 'ai2',
     valuerange = (0, 1372),
@@ -113,10 +114,11 @@ Mod('interlocks',
     control = 'T',
     wall_limit = 60,
     vacuum_limit = 0.001,
+    disabled_checks = 'T_extra',
    )
 
 Mod('p',
-    'frappy_psi.ionopimax.LogVoltageInput',
+    'frappy_psi.furnace.PKRgauge',
     'pressure reading',
     addr = 'av1',
     rawrange = (1.82, 8.6),
diff --git a/frappy_psi/furnace.py b/frappy_psi/furnace.py
index 1473843c..f7c04d08 100644
--- a/frappy_psi/furnace.py
+++ b/frappy_psi/furnace.py
@@ -20,7 +20,7 @@
 """interlocks for furnace"""
 
 from frappy.core import Module, Writable, Attached, Parameter, FloatRange, Readable,\
-     BoolType, ERROR, IDLE, Command
+     BoolType, ERROR, IDLE, Command, StringType
 from frappy.errors import ImpossibleError
 from frappy.ctrlby import WrapControlledBy
 from frappy_psi.picontrol import PImixin
@@ -53,19 +53,20 @@ class Interlocks(Writable):
                              default = 530, readonly = False)
     extra_T_limit = Parameter('maximum extra temperature', FloatRange(0, unit='degC'),
                              default = 530, readonly = False)
+    disabled_checks = Parameter('checks to disable', StringType(),
+                             value = '', readonly = False)
 
     _off_reason = None  # reason triggering interlock
     _conditions = ''  # summary of reasons why locked now
+    _sensor_checks = ()
 
-    def initModule(self):
-        super().initModule()
-        self._sensor_checks = [
-            (self.wall_T, 'wall_limit'),
-            (self.main_T, 'main_T_limit'),
-            (self.extra_T, 'extra_T_limit'),
-            (self.htr_T, 'htr_T_limit'),
-            (self.vacuum, 'vacuum_limit'),
-        ]
+    SENSOR_MAP = {
+        'wall_T': 'wall_limit',
+        'main_T': 'main_T_limit',
+        'extra_T': 'extra_T_limit',
+        'htr_T': 'htr_T_limit',
+        'vacuum': 'vacuum_limit',
+    }
 
     def write_target(self, value):
         if value:
@@ -93,13 +94,21 @@ class Interlocks(Writable):
             self.log.warning('switch off relais %r %r', self.relais.value, self.relais.target)
         self.relais.write_target(False)
 
+    def write_disabled_checks(self, value):
+        disabled = set(value.split())
+        self._sensor_checks = []
+        for att, limitname in self.SENSOR_MAP.items():
+            obj = getattr(self, att)
+            if obj and obj.name not in disabled:
+                self.log.info('info %r %r %r', att, obj.name, disabled)
+                self._sensor_checks.append((obj, limitname))
+
     def read_status(self):
         conditions = []
         if self.flowswitch and self.flowswitch.value == 0:
             conditions.append('no cooling water')
+
         for sensor, limitname in self._sensor_checks:
-            if sensor is None:
-                continue
             if sensor.value > getattr(self, limitname):
                 conditions.append(f'above {sensor.name} limit')
             if sensor.status[0] >= ERROR:
@@ -155,3 +164,15 @@ class PI2(PI):
         if not self.control_active:
             self.output_module.write_target(target)
         super().write_target(target)
+
+
+class PRtransmitter(CurrentInput):
+    rawrange = (0.004, 0.02)
+    extendedrange = (0.0036, 0.021)
+
+
+class PKRgauge(LogVoltageInput):
+    rawrange = (1.82, 8.6)
+    valuerange = (5e-9, 1000)
+    extendedrange = (0.5, 9.5)
+    value = Parameter(unit='mbar')