Merge pull request #135 from SiLab-Bonn/enhance_temperature

Enhance temperature control and measurement

basil/HL/sensirion_ekh4.py

@@ -16,89 +16,102 @@ class sensirionEKH4(HardwareLayer):
     '''Driver for the Sensirion EK-H4 multiplexer box. Can be used to read up to 4 channels of sensirion sensors for humidity and temperature
     (http://www.sensirion.com/en/products/humidity-temperature/evaluation-kits/ek-h4/).
     A TLV protocoll via serial port is used with 115200 baud rate. The type byte definitions cannot be found online...
-    The data returned by the device is often too long, especially for the humidity read out. Still it is interpreted.
-    But to avoid unreasonable values a max_value can be set (e.g. rel. humidity < 100). If this values is exceeded None is set for that channel.
+    The data returned by the device is often too long. Different cases are handled and not reconsturctable channels are set to None.
     '''
 
     def __init__(self, intf, conf):
         super(sensirionEKH4, self).__init__(intf, conf)
 
     def init(self):
         super(sensirionEKH4, self).init()
-        self.read()  # clear trash
-        # set readout every second
-        self.ask(r"7e230200013102010c25010e2601033a7e")
+        self._write(r"7e230200013102010c25010e2601033a7e")  # set update interval to 1Hz
+        self._intf.read(size=1024)  # clear buffer
 
-    def write(self, command):
+    def _write(self, command):
         self._intf.write(binascii.a2b_hex(command))
 
-    def ask(self, command):
-        '''Read response to command and convert it to 16-bit integer.
-        Returns : list of values
-        '''
-        self._intf.read(size=1024)  # Make sure that buffer is cleared
-        self.write(command)
+    def _read(self):
+        word = ''
+        data_flg = 0
+        for _ in range(1024):
+            b = codecs.encode(self._intf.read(size=1), 'hex_codec').decode('utf-8')
+
+            if b == '7e':       # delimiter
+                if data_flg == 0:    # data word comes next
+                    data_flg = 1
+                else:           # data word finished
+                    break
+            elif data_flg == 1:
+                word += b
+
+        return word
+
+    def _query(self, command):
+        self._write(command)
         time.sleep(0.1)
-        return self.read()
-
-    def read(self):
-        answer = []
-        flg = 0
-        for _ in range(1024):  # data assumed to be less than 1024 words
-            a = codecs.encode(self._intf.read(size=1), 'hex_codec').decode('utf-8')
-            if a == '':
-                break
-            elif flg == 0 and a == '7e':
-                flg = 1
-            elif flg == 1 and a == '7e':
-                break
-            elif flg == 1:
-                answer.append(a)
-        return answer
-
-    def get_temperature(self, channel=None, min_val=-40, max_val=200):
-        values = []
-        ret = self.ask(r"7e4700b87e")
-        for j in range(4):
-            if ret[2 + 2 * j] == "7f" and ret[2 + 2 * j + 1] == "ff":
-                values.append(None)
-            else:
-                values.append(self.cal_ret(ret[2 + 2 * j] + ret[2 + 2 * j + 1]))
+        return self._read()
+
+    def _calc_value(self, value):
+        '''
+            Calculate two's complement of signed binary, if applicable.
+        '''
+        bits = 16
+        value = int(value, 16)
+        if (value & (1 << (bits - 1))) != 0:  # if sign bit is set, e.g., 8bit: 128-255
+            value = value - (1 << bits)  # compute negative value
+        return float(value) / 100.0
+
+    def _get_values(self, cmd):
+        '''
+            Retrieve raw values via self._query and do error correction if possible
+            First 4 characters of data word are unknown ("4608", "4708" or "4808").
+            Last two characters seem to be some kind of checksum?
+            In between there should be 16 characters, 4 per channel. Sometimes it's more.
+            Two cases can be distinguished here:
+                1. Some kind of common error code "7d31" plus an additional byte.
+                    In this case, the affected channel is set to None,
+                    the extra byte is removed and the other channels are interpreted as usual.
+                2. Varying amount of extra bytes with no recognizable error code.
+                    In this case, nothing can be reconstructed and all channels are set to None.
+
+            Case 1 is reproducable for temperatures between about 43.53C and 46.1C...?
+        '''
+        ret = self._query(cmd)[4:-2]
+        # Cut off extra bytes in case of error
+        for i in range(0, 16, 4):
+            if ret[i:i + 4] == '7d31':
+                ret = ret[:i + 4] + ret[i + 6:]
+
+        if len(ret) != 16:  # wrong number of bytes despite attempted error correction
+            values = [None, None, None, None]
+        else:
+            values = []
+            data = [ret[j:j + 4] for j in range(0, len(ret), 4)]
+            for i, d in enumerate(data):
+                if d == '7d31' or d == '7fff':  # Error or no sensor connected
+                    values.append(None)
+                else:
+                    values.append(self._calc_value(d))
+
+        return values
+
+    def get_temperature(self, channel=None):
+        values = self._get_values(r"7e4700b87e")
 
         if channel is None:
             return values
         return values[channel]
 
-    def get_humidity(self, channel=None, min_val=0, max_val=100):
-        values = []
-        ret = self.ask(r"7e4600b97e")
-        for j in range(4):
-            if ret[2 + 2 * j] == "7f" and ret[2 + 2 * j + 1] == "ff":
-                values.append(None)
-            else:
-                values.append(self.cal_ret(ret[2 + 2 * j] + ret[2 + 2 * j + 1]))
+    def get_humidity(self, channel=None):
+        values = self._get_values(r"7e4600b97e")
 
         if channel is None:
             return values
         return values[channel]
 
-    def get_dew_point(self, channel=None, min_val=-40, max_val=100):
-        values = []
-        ret = self.ask(r"7e4800b77e")
-        for j in range(4):
-            if ret[2 + 2 * j] == "7f" and ret[2 + 2 * j + 1] == "ff":
-                values.append(None)
-            else:
-                values.append(self.cal_ret(ret[2 + 2 * j] + ret[2 + 2 * j + 1]))
+    def get_dew_point(self, channel=None):
+        values = self._get_values(r"7e4800b77e")
 
         if channel is None:
             return values
         return values[channel]
-
-    def cal_ret(self, value):
-        bits = 16
-        value = int(value, 16)
-        # compute the 2's compliment of int value
-        if (value & (1 << (bits - 1))) != 0:  # if sign bit is set, e.g., 8bit: 128-255
-            value = value - (1 << bits)  # compute negative value
-        return float(value) / 100.0  # return positive value as is

basil/HL/weiss_labevent.py

@@ -9,25 +9,41 @@
 
 from basil.HL.RegisterHardwareLayer import HardwareLayer
 
+logger = logging.getLogger(__name__)
+
 
 class weissLabEvent(HardwareLayer):
     '''
-        Driver for Weiss LabEvent T/210/70/5 climate chamber.
+        Driver for Weiss LabEvent T/210/70/5 climate chamber. Commands extracted from
+        https://github.com/IzaakWN/ClimateChamberMonitor/blob/master/chamber_commands.py
     '''
 
+    CHAMBER_TYPE = 'LabEvent T/210/70/5'
+
     RETURN_CODES = {
         1: "Command is accepted and executed.",
         -5: "Command number transmitted is unidentified!",
         -6: "Too few or incorrect parameters entered!",
         -8: "Data could not be read!",
     }
 
+    STATUS_CODES = {
+        1: 'Test not running (Idle)',
+        3: 'Test running',
+        4: 'Warnings present',
+        8: 'Alarms present'
+    }
+
     def __init__(self, intf, conf):
         super(weissLabEvent, self).__init__(intf, conf)
 
     def init(self):
         super(weissLabEvent, self).init()
 
+        info = self.get_info()
+        if info != self.CHAMBER_TYPE:
+            raise ValueError("Not the expected climatechamber! Expected '{0}', chamber reported '{1}'.".format(self.CHAMBER_TYPE, info))
+
     def query(self, cmd):
         ret = self._intf.query(cmd, buffer_size=512)[0]
         dat = [d.decode('ascii') for d in ret.split(b'\xb6')]
@@ -37,18 +53,77 @@ def query(self, cmd):
             data = dat[1]
         except IndexError:
             data = None
-        logging.debug('Return code {0}: {1}'.format(code, self.RETURN_CODES[code]))
+        logger.debug('Return code {0}: {1}'.format(code, self.RETURN_CODES[code]))
         if code != 1:
-            logging.error('Return code {0}: {1}'.format(code, self.RETURN_CODES[code]))
+            logger.error('Return code {0}: {1}'.format(code, self.RETURN_CODES[code]))
 
         return code, data
 
-    def get_temperature(self):
-        return float(self.query(b'11004\xb61\xb61')[1])
+    def _get_feature_status(self, id):
+        '''
+            Installed features:
+            1 - Condensation protection
+            2 - Not installed
+            3 - Not installed
+            4 - Compressed air / N2
+            5 - Air Dryer
+            6 - Not installed
+        '''
+
+        if id not in range(1, 7):
+            raise ValueError('Invalid feature id!')
+
+        feature_name = self.query(b'14010\xb61\xb6' + str(id).encode('ascii'))[1]
+        feature_status = self.query(b'14003\xb61\xb6' + str(id + 1).encode('ascii'))[1]  # For get and set status, id = id + 1
+        logger.debug('Feature {0} has status {1}'.format(feature_name, feature_status))
+        return bool(int(feature_status))
+
+    def _set_feature_status(self, id, value):
+        return self.query(b'14001\xb61\xb6' + str(id + 1).encode('ascii') + b'\xb6' + str(int(value)).encode('ascii'))  # For get and set status, id = id + 1
+
+    def get_info(self):
+        return self.query(b'99997\xb61\xb61')[1]
+
+    def get_status(self):
+        status_code = int(self.query(b'10012\xb61\xb61')[1])
+        status = '{0}: {1}'.format(status_code, self.STATUS_CODES[status_code])
+        return status
 
     def start_manual_mode(self):
         if not self.query(b'14001\xb61\xb61\xb61')[0] == 1:
-            logging.error('Could not start manual mode!')
+            logger.error('Could not start manual mode!')
+
+    def stop_manual_mode(self):
+        if not self.query(b'14001\xb61\xb61\xb60')[0] == 1:
+            logger.error('Could not stop manual mode!')
+
+    def get_temperature(self):
+        return float(self.query(b'11004\xb61\xb61')[1])
 
     def set_temperature(self, target):
-        self.query(b'11001\xb61\xb61\xb6' + str(target).encode('ascii'))
+        if not self.query(b'11001\xb61\xb61\xb6' + str(target).encode('ascii'))[0] == 1:
+            logger.error('Could not set temperature!')
+
+    def get_temperature_setpoint(self):
+        return float(self.query(b'11002\xb61\xb61')[1])
+
+    def get_condensation_protection(self):
+        return self._get_feature_status(1)
+
+    def set_condensation_protection(self, value):
+        if not self._set_feature_status(1, value)[0] == 1:
+            logger.error('Could not set condensation protection!')
+
+    def get_compressed_air(self):
+        return self._get_feature_status(4)
+
+    def set_compressed_air(self, value):
+        if not self._set_feature_status(4, value)[0] == 1:
+            logger.error('Could not set compressed air / N2!')
+
+    def get_air_dryer(self):
+        return self._get_feature_status(5)
+
+    def set_air_dryer(self, value):
+        if not self._set_feature_status(5, value)[0] == 1:
+            logger.error('Could not set air dryer!')

examples/lab_devices/temperature_control.py

@@ -5,22 +5,15 @@
 # ------------------------------------------------------------
 #
 
-''' This script shows how to read temperature/humidity with Sensition sensors and how to set temperature using a Binder MK 53 climate chamber.
-The Sensition sensors are read using the Sensirion EK-H4 multiplexer box from the evaluation kit. A serial TL has to be used
-(http://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/Humidity/Sensirion_Humidity_EK-H4_Datasheet_V3.pdf).
-For the communication with the Binder MK 53 also  a serial TL has to be used (http://www.binder-world.com).
+'''
+    This script shows how to set temperature using a Binder MK 53 climate chamber.
+    For the communication with the Binder MK 53 also  a serial TL has to be used (http://www.binder-world.com).
+    The newer Weiss Labevent climatechamber uses a direct TCP/IP connection.
 '''
 
 
 from basil.dut import Dut
 
-# Sensirion sensor readout
-dut = Dut('sensirionEKH4_pyserial.yaml')
-dut.init()
-print(dut['Thermohygrometer'].get_temperature())
-print(dut['Thermohygrometer'].get_humidity())
-print(dut['Thermohygrometer'].get_dew_point())
-
 # Binder MK 53 control
 dut = Dut('binderMK53_pyserial.yaml')
 dut.init()
@@ -30,17 +23,10 @@
 temperature_target = dut['Climatechamber'].get_temperature_target()
 dut['Climatechamber'].set_temperature(temperature_target)
 
-# Weiss SB 22 control
-dut = Dut('WeissSB22_pyserial.yaml')
-dut.init()
-print(dut['Climatechamber'].get_temperature())
-print(dut['Climatechamber'].get_digital_ch())
-temperature_target = dut['Climatechamber'].get_temperature_target()
-dut['Climatechamber'].set_temperature(temperature_target)
-
 # New Weiss Labevent control
 dut = Dut('WeissLabEvent_socket.yaml')
 dut.init()
 dut['Climatechamber'].start_manual_mode()
-dut['Climatechamber'].set_temperature(-10)
+dut['Climatechamber'].set_temperature(20)
+dut['Climatechamber'].set_air_dryer(True)   # Make sure the air dryer is turned on
 print(dut['Climatechamber'].get_temperature())

examples/lab_devices/temperature_sensors.py

@@ -0,0 +1,22 @@
+#
+# ------------------------------------------------------------
+# Copyright (c) All rights reserved
+# SiLab, Institute of Physics, University of Bonn
+# ------------------------------------------------------------
+#
+
+'''
+    This script shows how to read temperature/humidity with Sensition sensors.
+    The Sensition sensors are read using the Sensirion EK-H4 multiplexer box from the evaluation kit. A serial TL has to be used
+    (http://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/Humidity/Sensirion_Humidity_EK-H4_Datasheet_V3.pdf).
+'''
+
+
+from basil.dut import Dut
+
+# Sensirion sensor readout
+dut = Dut('sensirionEKH4_pyserial.yaml')
+dut.init()
+print(dut['Thermohygrometer'].get_temperature())
+print(dut['Thermohygrometer'].get_humidity())
+print(dut['Thermohygrometer'].get_dew_point())