Code:

import time,ostestOffline = os.getenv("TEST_OFFLINE", True)import pybullet as pimport pybullet_data if testOffline ==True:   import pybullet as p   import pybullet_data else:   import minimalmodbus as modbus#cartpole1 = p.loadURDF("cartpole.urdf")if testOffline ==True:    print("pybullet model loaded")else:    drive = ""    slave = ""        print("Module flyby-modbus loaded.")#################################################################################                    CONTROL the Motor Drive                             #### All CONTROL functions return { True | False } based on success/fail result.###############################################################################if testOffline ==True:    def connectp():        p.connect(p.GUI)        p.setAdditionalSearchPath(pybullet_data.getDataPath())        global cartpole1        cartpole1 = p.loadURDF("cartpole.urdf")        try:            reset()                        print("connected")                        return cartpole1        except Exception as e:            print(e)            return Falseelse:            def connect(connectionPort='/dev/cu.SLAB_USBtoUART', slaveID=7, mode='ascii', baudRate=9600, byteSize=8):        global drive, slave        slave = slaveID        try:            drive = modbus.Instrument(connectionPort, int(slaveID))            drive.mode = mode            drive.serial.baudrate = baudRate            drive.serial.bytesize = byteSize            reset()            print(drive)            return True        except Exception as e:            print(e)            return Falseif testOffline ==True:    def startp(controlMode='DIGITAL', direction='CW'):        if controlMode=='DIGITAL':            if direction=='CW':                 p.setJointMotorControl2(cartpole1,1,                                         targetVelocity=6)            elif direction=='CCW':                p.setJointMotorControl2(cartpole1,1,                                         targetVelocity=-6)        elif controlMode=='POSITION':            p.setJointMotorControl2(cartpole1,1,                                         p.POSITION_CONTROL)        try:            if not drive:                connectp()            else:                          return True        except Exception as e:            print(e)            return False        else:    def start(controlMode='DIGITAL', direction='CW'):        if controlMode=='DIGITAL':            if direction=='CW':                registerValue = 257            elif direction=='CCW':                registerValue = 265        elif controlMode=='POSITION':            registerValue = 513            try:            if not drive:                connect()            else:                result = drive.write_register(2, registerValue, functioncode=6)                return True        except Exception as e:            print(e)            return Falseif testOffline ==True:    def disconnect():        p.disconnect(p.GUI)              try:            if not drive:                connectp()            else:                return True        except Exception as e:            print(e)            return False        else:    def stop(controlMode='DIGITAL', direction='CW'):        if controlMode=='DIGITAL':            if direction=='CW':                registerValue = 256            elif direction=='CCW':                registerValue = 264        elif controlMode=='POSITION':            registerValue = 512            try:            if not drive:                connect()            else:                result = drive.write_register(2, registerValue, functioncode=6)                return True        except Exception as e:            print(e)            return Falseif testOffline ==True:    def brakep(controlMode='DIGITAL', direction='CW'):        if controlMode=='DIGITAL':            if direction=='CW':                 p.setJointMotorControl2(cartpole1,1,                                         targetVelocity=6)            elif direction=='CCW':                p.setJointMotorControl2(cartpole1,1,                                         targetVelocity=-6)               try:                if not drive:                    connectp()                else:                    return True            except Exception as e:                print(e)                return Falseelse:            def brake(direction='CW'):        if direction=='CW':            registerValue = 260        elif direction=='CCW':            registerValue = 268        try:            if not drive:                connect()            else:                result = drive.write_register(2, registerValue, functioncode=6)                return True        except Exception as e:            print(e)            return Falsedef reset():    try:        if not drive:            connect()        else:            drive.write_register(2, 0, functioncode=6)            drive.write_register(3, 0, functioncode=6)            drive.write_register(4, 32, functioncode=6)            drive.write_register(6, 16, functioncode=6)            drive.write_register(8, 32, functioncode=6)            drive.write_register(10, 334, functioncode=6)            drive.write_register(12, 20000, functioncode=6)            drive.write_register(14, 2048, functioncode=6)            drive.write_register(16, 0, functioncode=6)            drive.write_register(18, 0, functioncode=6)            drive.write_register(20, 0, functioncode=6)            return True    except Exception as e:        print(e)        return False#################################################################################                      READ from Modbus Registers                       ##### All READ functions return { <value>|"ERROR" } based on success/fail result.###############################################################################if testOffline ==True:    def speed(cartpole1):                while(1):             p.setGravity(0, 0, -10)             js = p.getJointState(cartpole1, 1)             # print("position=", js[0], "velocity=", js[1])             return js[1]             time.sleep(0.01)else:        def readRegister(registerNumber, readNextCount=0):        try:            if not drive:                connect()            else:                result = drive.read_register(registerNumber, readNextCount, functioncode=3)                return str(result)        except Exception as e:            print(e)            return "ERROR"        def getSlaveID():        return readRegister(registerNumber=1, readNextCount=0)        def getControlMode():        return readRegister(registerNumber=2, readNextCount=0) + "|" + readRegister(registerNumber=3, readNextCount=0)        def getProportionalGain():        return readRegister(registerNumber=4, readNextCount=0)        def getIntegralGain():        return readRegister(registerNumber=6, readNextCount=0)        def getFeedForwardGain():        return readRegister(registerNumber=8, readNextCount=0)        def getLinesPerRotation():        return readRegister(registerNumber=10, readNextCount=0)        def getAcceleration():        return readRegister(registerNumber=12, readNextCount=0)        def getSpeed():        return readRegister(registerNumber=14, readNextCount=0)        def getSpeedFeedback():        # speed is a positive number between 0 (0x0000) and 65535 (0xFFFF)        # 0 to 18000 is the range of speed this motor supports, however, setting a speed of 18000 should be avoided in the first place        minRange = 0        maxRange = 65535            spdFdbk = readRegister(registerNumber=24, readNextCount=0)            # if the spdFdbk is less than 32767, that means motor is in CW direction -- it must be returned absolute        if int(spdFdbk) < 32767:            pass        # if the spdFdbk is more than 32767, that means motor is in CCW direction -- it must be adjusted accordingly        elif int(spdFdbk) > 32767:            spdFdbk = maxRange - int(spdFdbk)            return spdFdbk            def getPositionFeedback():        # position is a positive number between 0 to 4294967285        lsb = readRegister(registerNumber=20, readNextCount=0)        msb = readRegister(registerNumber=22, readNextCount=0)            # convert position feedback to hexadecimal with MSB and LSB joining to make 32-bits        lsbInHex = hex(int(lsb))[2:].zfill(4)        msbInHex = hex(int(msb))[2:].zfill(4)        pos = int("0x" + msbInHex + lsbInHex, 0)        return pos##############################################################################                      WRITE to Modbus Registers                      #### All READ functions return { True | False } based on success/fail result.############################################################################if testOffline ==True:     global cartpole1    p.setJointMotorControl2(cartpole1,                        1,                        p.POSITION_CONTROL,                        targetPosition=1000,                        targetVelocity=6,                        force=5,                        positionGain=1.9,                        velocityGain=0.25,                        maxVelocity=10)    #return a[2]else:      def writeRegister(registerNumber, registerValue):        try:            if not drive:                connect()            else:                result = drive.write_register(registerNumber, registerValue, functioncode=6)                return True        except Exception as e:            print(e)            return False        def setProportionalGain(proportionalGain=32):        return writeRegister(registerNumber=4, registerValue=int(proportionalGain))        def setIntegralGain(integralGain=16):        return writeRegister(registerNumber=6, registerValue=int(integralGain))        def setFeedForwardGain(feedForwardGain=32):        return writeRegister(registerNumber=8, registerValue=int(feedForwardGain))        def setLinesPerRotation(linesPerRotation=334):        return writeRegister(registerNumber=10, registerValue=int(linesPerRotation))        def setAcceleration(acceleration=20000):        return writeRegister(registerNumber=12, registerValue=int(acceleration))        def setSpeed(speed=2048):        # speed is a positive number between 0 (0x0000) and 65535 (0xFFFF)        # 0 to 18000 is the range of speed this motor supports, however, setting a speed of 18000 should be avoided in the first place        minRange = 0        maxRange = 65535            if minRange <= speed <= maxRange:            writeRegister(registerNumber=14, registerValue=int(speed))            return            # gotoPosition() instructs the motor drive to execute "immediately" by rotating it CW or CCW based on desired position requested.    def gotoPosition(position=0):        # position is a positive number between 0 (0x00000000) and 4294967285 (0xFFFFFFFF)        minRange = 0        maxRange = 4294967295            if minRange <= position <= maxRange:            # convert position to hexadecimal with 32-bits, before extracting msb & lsb            posInHex = hex(position)[2:].zfill(8)            msb = "0x" + posInHex[0:4]            lsb = "0x" + posInHex[4:8]            writeRegister(registerNumber=16, registerValue=int(lsb, 0))            writeRegister(registerNumber=18, registerValue=int(msb, 0))                #############################            #####  Start the motor! #####            start(controlMode='POSITION')            # Keep waiting until the motor has reached the desired position        while getPositionFeedback()!=position:            pass            return