Dependency-free reading of the Hopi HP-9800 power meter (USB version) in python. Windows or Linux etc.

Hopi_HP-9800_Python_simple.py

#
# By Richard Aplin, released into the public domain for any purpose, no warranties implied, 8/17/2022
#
#
import struct
import serial

#Super lightweight code to read Hopi HP-9800 power meter

class Hopi(object):

    REGS=[
            ("Active Power","W"),
            ("RMS Current","A"),
            ("Voltage RMS","V"),
            ("Frequency","Hz"),
            ("Power Factor","pf"),
            ("Annual Power","KWH"),
            ("Active Power","KWH"),
            ("Reactive Power","KWH"),
            ("Load Time","mins"),
        ]

    def __init__(self,port="COM4"):
        baud=9600
        self.debug=False #True
        
        self.ser=serial.Serial(port,baudrate=baud,timeout=1)
    
    def crc(self,data):
        poly=0xa001
        crc = 0xFFFF
        for b in data:
            cur_byte = 0xFF & ord(b)
            for _ in range(0, 8):
                if (crc & 0x0001) ^ (cur_byte & 0x0001):
                    crc = (crc >> 1) ^ poly
                else:
                    crc >>= 1
                cur_byte >>= 1
        return struct.pack("<H",crc&0xffff)
    
    def read(self):
        #self.readRegs(4,2) #1,10)
        self.regs=self.readRegs(0,len(self.REGS)*2) #1,10)
        
    def display(self):
        dmax=99 #can limit how many regs displayed
        for idx,value in enumerate(self.regs):
            name,unit=self.REGS[idx]
            print "%s\t%.3f%s" % (name,value,unit)
            dmax-=1
            if dmax==0:
                break
        
        
    def phex(self,data):
        s=" ".join(["%02x" % ord(d) for d in data])
        return s
        
    def readRegs(self,first,count,addr=1):
        cmd=0x03
        fout=[]
        m=struct.pack(">BBHH",addr,cmd,first,count)
        m+=self.crc(m)
        if self.debug:
            print "\t>",self.phex(m)
        self.ser.write(m)
        replyLen=3+(count*2)+2
        r=self.ser.read(replyLen)
        if self.debug:
            print "\t<",self.phex(r)
        if len(r)!=replyLen:
            print "Bad reply len",len(r)
            return
        ccrc=self.crc( r[:-2] )
        if ccrc!=r[-2:]:
            print "bad crc"
            return
        addr,f,bcount=struct.unpack(">BBB",r[:3])
        if addr==addr and f==cmd:
            #unpack floats from hopi
            d=r[3:-2]
            fpos=0
            while fpos<len(d):
                fpval=d[fpos:fpos+4]
                v=struct.unpack("<f",fpval)[0]
                fout.append(v)
                fpos+=4
                #print fpos/2,v
            return fout
        else:
            print "Bad reply"
            
            
        
h=Hopi(port="COM4")
while True:
    h.read()
    h.display()
    

Hi! Could you please consider adding a license? I'm currently porting to python 3 and making some other changes and would like to redistribute them later, but without a license it's "all rights reserved" and I can't legally do so.
Thanks!

sure thing

Thank you!