diff --git a/frappy/client/__init__.py b/frappy/client/__init__.py
index 2352bba..123817b 100644
--- a/frappy/client/__init__.py
+++ b/frappy/client/__init__.py
@@ -318,8 +318,8 @@ class SecopClient(ProxyClient):
                     # inform that the other party still uses a legacy identifier
                     # see e.g. Frappy Bug #4659 (https://forge.frm2.tum.de/redmine/issues/4659)
                     if not self.secop_version.startswith(IDENTPREFIX):
-                        self.log.warning('SEC-Node replied with legacy identify reply: %s'
-                                         % self.secop_version)
+                        self.log.warning('SEC-Node replied with legacy identify reply: %s',
+                                         self.secop_version)
 
                     # now its safe to do secop stuff
                     self._running = True
diff --git a/frappy/client/interactive.py b/frappy/client/interactive.py
index 8cf9862..e53d4ab 100644
--- a/frappy/client/interactive.py
+++ b/frappy/client/interactive.py
@@ -186,7 +186,7 @@ class Module:
                 elif item in LOG_LEVELS:
                     self._log_level = item
                 else:
-                    self._secnode.log.error('can not set %r on module %s' % (item, self._name))
+                    self._secnode.log.error('can not set %r on module %s', item, self._name)
             self._watched_params = params
         print('--- %s:\nlog: %s, watch: %s' % (self._name, self._log_level, ' '.join(self._watched_params)))
 
diff --git a/frappy/gui/mainwindow.py b/frappy/gui/mainwindow.py
index 1fb93ea..a2830e9 100644
--- a/frappy/gui/mainwindow.py
+++ b/frappy/gui/mainwindow.py
@@ -272,7 +272,7 @@ class MainWindow(QMainWindow):
             # disconnect node from all events
             node.terminate_connection()
             self._nodeWidgets.pop(node.contactPoint)
-            self.log.debug("Closing tab with node %s" % node.nodename)
+            self.log.debug("Closing tab with node %s", node.nodename)
         self.tab.removeTab(index)
 
     def _rebuildAdvanced(self, advanced):
diff --git a/frappy/io.py b/frappy/io.py
index f932086..9060797 100644
--- a/frappy/io.py
+++ b/frappy/io.py
@@ -98,11 +98,11 @@ class HasIodev(HasIO):
 class IOBase(Communicator):
     """base of StringIO and BytesIO"""
     uri = Property("""uri for serial connection
-    
+
                    one of the following:
-                   
+
                    - ``tcp://<host address>:<portnumber>`` (see :class:`frappy.lib.asynconn.AsynTcp`)
-                   
+
                    - ``serial://<serial device>?baudrate=<value>...`` (see :class:`frappy.lib.asynconn.AsynSerial`)
                    """, datatype=StringType())
     timeout = Parameter('timeout', datatype=FloatRange(0), default=2)
@@ -196,7 +196,7 @@ class IOBase(Communicator):
             try:
                 removeme = not cb()
             except Exception as e:
-                self.log.error('callback: %s' % e)
+                self.log.error('callback: %s', e)
                 removeme = True
             if removeme:
                 self._reconnectCallbacks.pop(key)
diff --git a/frappy/persistent.py b/frappy/persistent.py
index 2a54957..c48373a 100644
--- a/frappy/persistent.py
+++ b/frappy/persistent.py
@@ -108,7 +108,7 @@ class PersistentMixin(Module):
                     result[pname] = self.parameters[pname].datatype.import_value(value)
             except Exception as e:
                 # ignore invalid persistent data (in case parameters have changed)
-                self.log.warning('can not restore %r to %r (%r)' % (pname, value, e))
+                self.log.warning('can not restore %r to %r (%r)', pname, value, e)
         return result
 
     def loadParameters(self):
diff --git a/frappy/protocol/dispatcher.py b/frappy/protocol/dispatcher.py
index 78f18a5..8efe610 100644
--- a/frappy/protocol/dispatcher.py
+++ b/frappy/protocol/dispatcher.py
@@ -140,8 +140,8 @@ class Dispatcher:
         self.reset_connection(conn)
 
     def register_module(self, moduleobj, modulename, export=True):
-        self.log.debug('registering module %r as %s (export=%r)' %
-                       (moduleobj, modulename, export))
+        self.log.debug('registering module %r as %s (export=%r)',
+                       moduleobj, modulename, export)
         self._modules[modulename] = moduleobj
         if export:
             self._export.append(modulename)
@@ -168,15 +168,15 @@ class Dispatcher:
         return self._export[:]
 
     def export_accessibles(self, modulename):
-        self.log.debug('export_accessibles(%r)' % modulename)
+        self.log.debug('export_accessibles(%r)', modulename)
         if modulename in self._export:
             # omit export=False params!
             res = OrderedDict()
             for aobj in self.get_module(modulename).accessibles.values():
                 if aobj.export:
                     res[aobj.export] = aobj.for_export()
-            self.log.debug('list accessibles for module %s -> %r' %
-                           (modulename, res))
+            self.log.debug('list accessibles for module %s -> %r',
+                           modulename, res)
             return res
         self.log.debug('-> module is not to be exported!')
         return OrderedDict()
@@ -282,7 +282,7 @@ class Dispatcher:
         will return return reply, may send replies to conn or
         activated connections in addition
         """
-        self.log.debug('Dispatcher: handling msg: %s' % repr(msg))
+        self.log.debug('Dispatcher: handling msg: %s', repr(msg))
 
         # play thread safe !
         # XXX: ONLY ONE REQUEST (per dispatcher) AT A TIME
@@ -292,7 +292,7 @@ class Dispatcher:
             if action == IDENTREQUEST:
                 action, specifier, data = '_ident', None, None
 
-            self.log.debug('Looking for handle_%s' % action)
+            self.log.debug('Looking for handle_%s', action)
             handler = getattr(self, 'handle_%s' % action, None)
 
             if handler:
diff --git a/frappy/protocol/interface/tcp.py b/frappy/protocol/interface/tcp.py
index 9a4132b..d925f27 100644
--- a/frappy/protocol/interface/tcp.py
+++ b/frappy/protocol/interface/tcp.py
@@ -131,7 +131,7 @@ class TCPRequestHandler(socketserver.BaseRequestHandler):
                         print('====================')
 
                 if not result:
-                    self.log.error('empty result upon msg %s' % repr(msg))
+                    self.log.error('empty result upon msg %s', repr(msg))
                 if result[0].startswith(ERRORPREFIX) and not detailed_errors:
                     # strip extra information
                     result[2][2].clear()
@@ -193,7 +193,7 @@ class TCPServer(socketserver.ThreadingTCPServer):
         port = int(options.pop('uri').split('://', 1)[-1])
         self.detailed_errors = options.pop('detailed_errors', False)
 
-        self.log.info("TCPServer %s binding to port %d" % (name, port))
+        self.log.info("TCPServer %s binding to port %d", name, port)
         for ntry in range(5):
             try:
                 socketserver.ThreadingTCPServer.__init__(
@@ -204,10 +204,10 @@ class TCPServer(socketserver.ThreadingTCPServer):
                     # this may happen despite of allow_reuse_address
                     time.sleep(0.3 * (1 << ntry))  # max accumulated sleep time: 0.3 * 31 = 9.3 sec
                 else:
-                    self.log.error('could not initialize TCP Server: %r' % e)
+                    self.log.error('could not initialize TCP Server: %r', e)
                     raise
         if ntry:
-            self.log.warning('tried again %d times after "Address already in use"' % ntry)
+            self.log.warning('tried again %d times after "Address already in use"', ntry)
         self.log.info("TCPServer initiated")
 
     # py35 compatibility
diff --git a/frappy/proxy.py b/frappy/proxy.py
index 72640f2..e504191 100644
--- a/frappy/proxy.py
+++ b/frappy/proxy.py
@@ -73,7 +73,7 @@ class ProxyModule(HasIO, Module):
             props = remoteparams.get(pname, None)
             if props is None:
                 if pobj.export:
-                    self.log.warning('remote parameter %s:%s does not exist' % (self.module, pname))
+                    self.log.warning('remote parameter %s:%s does not exist', self.module, pname)
                 continue
             dt = props['datatype']
             try:
@@ -81,28 +81,28 @@ class ProxyModule(HasIO, Module):
                     dt.compatible(pobj.datatype)
                 else:
                     if props['readonly']:
-                        self.log.warning('remote parameter %s:%s is read only' % (self.module, pname))
+                        self.log.warning('remote parameter %s:%s is read only', self.module, pname)
                     pobj.datatype.compatible(dt)
                     try:
                         dt.compatible(pobj.datatype)
                     except Exception:
-                        self.log.warning('remote parameter %s:%s is not fully compatible: %r != %r'
-                                         % (self.module, pname, pobj.datatype, dt))
+                        self.log.warning('remote parameter %s:%s is not fully compatible: %r != %r',
+                                         self.module, pname, pobj.datatype, dt)
             except Exception:
-                self.log.warning('remote parameter %s:%s has an incompatible datatype: %r != %r'
-                                 % (self.module, pname, pobj.datatype, dt))
+                self.log.warning('remote parameter %s:%s has an incompatible datatype: %r != %r',
+                                 self.module, pname, pobj.datatype, dt)
         while cmds:
             cname, cobj = cmds.popitem()
             props = remotecmds.get(cname)
             if props is None:
-                self.log.warning('remote command %s:%s does not exist' % (self.module, cname))
+                self.log.warning('remote command %s:%s does not exist', self.module, cname)
                 continue
             dt = props['datatype']
             try:
                 cobj.datatype.compatible(dt)
             except BadValueError:
-                self.log.warning('remote command %s:%s is not compatible: %r != %r'
-                                 % (self.module, cname, cobj.datatype, dt))
+                self.log.warning('remote command %s:%s is not compatible: %r != %r',
+                                 self.module, cname, cobj.datatype, dt)
         # what to do if descriptive data does not match?
         # we might raise an exception, but this would lead to a reconnection,
         # which might not help.
diff --git a/frappy/server.py b/frappy/server.py
index a3fd319..87fbac0 100644
--- a/frappy/server.py
+++ b/frappy/server.py
@@ -211,7 +211,7 @@ class Server:
         missing_super = set()
         # all objs created, now start them up and interconnect
         for modname, modobj in self.modules.items():
-            self.log.info('registering module %r' % modname)
+            self.log.info('registering module %r', modname)
             self.dispatcher.register_module(modobj, modname, modobj.export)
             # also call earlyInit on the modules
             modobj.earlyInit()
@@ -278,7 +278,7 @@ class Server:
         if not start_events.wait():
             # some timeout happened
             for name in start_events.waiting_for():
-                self.log.warning('timeout when starting %s' % name)
+                self.log.warning('timeout when starting %s', name)
         self.log.info('all modules started')
         history_path = os.environ.get('FRAPPY_HISTORY')
         if history_path:
diff --git a/frappy/simulation.py b/frappy/simulation.py
index f3918cf..c5159b8 100644
--- a/frappy/simulation.py
+++ b/frappy/simulation.py
@@ -42,13 +42,13 @@ class SimBase:
                                      default=0.0)
 
                 def reader(self, pname=k):
-                    self.log.debug('simulated reading %s' % pname)
+                    self.log.debug('simulated reading %s', pname)
                     return self.parameters[pname].value
 
                 attrs['read_' + k] = reader
 
                 def writer(self, newval, pname=k):
-                    self.log.debug('simulated writing %r to %s' % (newval, pname))
+                    self.log.debug('simulated writing %r to %s', newval, pname)
                     self.parameters[pname].value = newval
                     return newval
 
diff --git a/frappy_demo/cryo.py b/frappy_demo/cryo.py
index 0b1a82c..c996422 100644
--- a/frappy_demo/cryo.py
+++ b/frappy_demo/cryo.py
@@ -237,8 +237,8 @@ class Cryostat(CryoBase):
             heater = self.heater
 
             heatflow = self.__heatLink(regulation, sample)
-            self.log.debug('sample = %.5f, regulation = %.5f, heatflow = %.5g'
-                           % (sample, regulation, heatflow))
+            self.log.debug('sample = %.5f, regulation = %.5f, heatflow = %.5g',
+                           sample, regulation, heatflow)
             newsample = max(0, sample + (self.__sampleLeak(sample) - heatflow)
                             / self.__sampleCP(sample) * h)
             # avoid instabilities due to too small CP
@@ -293,7 +293,7 @@ class Cryostat(CryoBase):
                 lastD = _D
 
                 self.log.debug('PID: P = %.2f, I = %.2f, D = %.2f, '
-                               'heater = %.2f' % (_P, _I, _D, heater))
+                               'heater = %.2f', _P, _I, _D, heater)
 
                 # check for turn-around points to detect oscillations ->
                 # increase damper
@@ -321,8 +321,8 @@ class Cryostat(CryoBase):
                 try:
                     self.setpoint = round(self.setpoint + clamp(
                         self.target - self.setpoint, -maxdelta, maxdelta), 3)
-                    self.log.debug('setpoint changes to %r (target %r)' %
-                                   (self.setpoint, self.target))
+                    self.log.debug('setpoint changes to %r (target %r)',
+                                   self.setpoint, self.target)
                 except (TypeError, ValueError):
                     # self.target might be None
                     pass
diff --git a/frappy_demo/modules.py b/frappy_demo/modules.py
index 1840072..6ae54d7 100644
--- a/frappy_demo/modules.py
+++ b/frappy_demo/modules.py
@@ -169,12 +169,12 @@ class MagneticField(Drivable):
             if self._state == self._state.enum.switch_on:
                 # wait until switch is on
                 if self._heatswitch.read_value() == 'on':
-                    self.log.debug('heatswitch is on -> ramp to %.3f' %
+                    self.log.debug('heatswitch is on -> ramp to %.3f',
                                    self.target)
                     self._state = self._state.enum.ramp
             if self._state == self._state.enum.ramp:
                 if self.target == self.value:
-                    self.log.debug('at field! mode is %r' % self.mode)
+                    self.log.debug('at field! mode is %r', self.mode)
                     if self.mode:
                         self.log.debug('at field -> switching heater off')
                         self._state = self._state.enum.switch_off
@@ -190,7 +190,7 @@ class MagneticField(Drivable):
             if self._state == self._state.enum.switch_off:
                 # wait until switch is off
                 if self._heatswitch.read_value() == 'off':
-                    self.log.debug('heatswitch is off at %.3f' % self.value)
+                    self.log.debug('heatswitch is off at %.3f', self.value)
                     self._state = self._state.enum.idle
             self.read_status()  # update async
             time.sleep(max(0.01, ts + loopdelay - time.time()))
diff --git a/frappy_mlz/amagnet.py b/frappy_mlz/amagnet.py
index f88330a..3517c42 100644
--- a/frappy_mlz/amagnet.py
+++ b/frappy_mlz/amagnet.py
@@ -162,7 +162,7 @@ class GarfieldMagnet(SequencerMixin, Drivable):
             minslope = min(entry[0]
                            for entry in self.calibrationtable.values())
             self.log.error(
-                'unconfigured calibration for symmetry %r' %
+                'unconfigured calibration for symmetry %r',
                 self._symmetry.value)
             return [minslope, 0, 0, 0, 0]
 
diff --git a/frappy_psi/ppms.py b/frappy_psi/ppms.py
index a624b69..bd210c6 100644
--- a/frappy_psi/ppms.py
+++ b/frappy_psi/ppms.py
@@ -386,10 +386,10 @@ class Temp(PpmsDrivable):
             return
         self.setpoint, self.workingramp, self.approachmode = self._last_settings = settings
         if self.setpoint != 10 or not self._wait_at10:
-            self.log.debug('read back target %g %r' % (self.setpoint, self._wait_at10))
+            self.log.debug('read back target %g %r', self.setpoint, self._wait_at10)
             self.target = self.setpoint
         if self.workingramp != 2 or not self._ramp_at_limit:
-            self.log.debug('read back ramp %g %r' % (self.workingramp, self._ramp_at_limit))
+            self.log.debug('read back ramp %g %r', self.workingramp, self._ramp_at_limit)
             self.ramp = self.workingramp
 
     def _write_params(self, setpoint, ramp, approachmode):
@@ -407,7 +407,7 @@ class Temp(PpmsDrivable):
         self._ramp_at_limit = ramp_at_limit
         self.calc_expected(setpoint, ramp)
         self.log.debug(
-            'change_temp v %r s %r r %r w %r l %r' % (self.value, setpoint, ramp, wait_at10, ramp_at_limit))
+            'change_temp v %r s %r r %r w %r l %r', self.value, setpoint, ramp, wait_at10, ramp_at_limit)
         self.comm_write('TEMP %g,%g,%d' % (setpoint, ramp, approachmode))
         self.read_params()
 
@@ -465,7 +465,7 @@ class Temp(PpmsDrivable):
         self.status = (StatusType.BUSY, 'changed target')
         self._last_change = time.time()
         self._write_params(target, self.ramp, self.approachmode)
-        self.log.debug('write_target %s' % repr((self.setpoint, target, self._wait_at10)))
+        self.log.debug('write_target %s', repr((self.setpoint, target, self._wait_at10)))
         return target
 
     def write_approachmode(self, value):
diff --git a/frappy_psi/trinamic.py b/frappy_psi/trinamic.py
index c0e706d..af7cb34 100644
--- a/frappy_psi/trinamic.py
+++ b/frappy_psi/trinamic.py
@@ -213,7 +213,7 @@ class Motor(PersistentMixin, HasIO, Drivable):
             self.log.error('saved encoder value (%.2f) does not match reading (%.2f %.2f)',
                            self.encoder, encoder_from_hw, adjusted_encoder)
             if adjusted_encoder != encoder_from_hw:
-                self.log.info('take next closest encoder value (%.2f)' % adjusted_encoder)
+                self.log.info('take next closest encoder value (%.2f)', adjusted_encoder)
             self._need_reset = True
             self.status = ERROR, 'saved encoder value does not match reading'
         self._write_axispar(adjusted_encoder - self.zero, ENCODER_ADR, ANGLE_SCALE, readback=False)