diff --git a/frappy_psi/bronkhorst.py b/frappy_psi/bronkhorst.py
index b870e9e5..bdd914d6 100644
--- a/frappy_psi/bronkhorst.py
+++ b/frappy_psi/bronkhorst.py
@@ -75,7 +75,7 @@ class Sensor(HasIO, Readable):
         reply = self.communicate(f':{length}{self.addr:02X}04{param}{param}')
         if reply[:11] != f':{length}{self.addr:02X}02{param}':
             return CommunicationFailedError(f'bad reply: {reply}')
-        val = int(reply[11:14], 16) / 32000 * scale
+        val = int(reply[11:15], 16) / 32000 * scale
         return val
 
     def read_value(self):
@@ -85,8 +85,8 @@ class Sensor(HasIO, Readable):
 class Controller(Sensor, Writable):
 
     def set_par(self, length, param, scale, value):
-        reply = self.communicate(f':{length}{self.addr:02X}01{param}{round(value/scale):04X}')
-        if reply[:8] != f':04{self.addr:02X}0000':
+        reply = self.communicate(f':{length}{self.addr:02X}01{param}{round(value * 32000 / scale):04X}')
+        if reply[:11] != f':04{self.addr:02X}000005':
             raise CommunicationFailedError(f'bad reply: {reply}')
         return self.get_par(length, param, scale)
 
@@ -94,8 +94,7 @@ class Controller(Sensor, Writable):
         return self.get_par(*SETPOINT, self.scale)
 
     def write_target(self, value):
-        val = value / self.scale * 32000
-        return self.set_par(*SETPOINT, self.scale, val)
+        return self.set_par(*SETPOINT, self.scale, value)
 
 
 class HasRamp(Drivable):