ValueError: 0x82 is not implemented in snap7.types

[maxitaxi13]

I made a simple sample code trying to read a value from Q0.0 on PLC S1212C.

import snap7
from snap7.util import *
from snap7.types import *
import time
import cv2
import numpy


#POVEZAVA S KRMILNIKOM
PLC=snap7.client.Client()
PLC.connect("192.168.0.1",0,1)

if PLC.get_connected():
    print("connected")
else:
    print("NOT connected")

time.sleep(1)
data=PLC.read_area(0x82, 0, 0, 1)
c=get_bool(data,0,0)

The code works just fine on a different computer where I have already installed snap7. On my ne computer i get the error

ValueError(f"{area} is not implemented in snap7.types")
ValueError: 130 is not implemented in snap7.types

I tried installing it using pip install and the instructions on https://python-snap7.readthedocs.io/en/latest/installation.html
but nothing worked, does anybody have any idea on what to do.

[swamper123]

Depending on which version you use, the solution is a bit different. My answer is for version 1.1 (last release):

The install should be finde, if I interpret your error right (hint: debugging line for line and see where it breaks).
It sounds that PLC.read_area() is the line who makes trouble.

I guess it's your first parameter in PLC.read_area(). It should be from type Areas, not the number directly. So in your code it should look like:

data = PLC.read_area(Areas.PE, 0, 0, 1)

You may want to take a look in the comments in the method as well:

        Example:
            >>> import snap7
            >>> client = snap7.client.Client()
            >>> client.connect("192.168.0.1", 0, 0)
            >>> buffer = client.read_area(snap7.types.Areas.DB, 1, 10, 4)  # Reads the DB number 1 from the byte 10 to the byte 14.

[swamper123]

And a Python style hint: You shouldn't do from XYZ import *. 😉
It doesn't look nice and you don't know from where what stuff is imported (and you avoid some traps as well).

[maxitaxi13]

Thank you so much, It works now. I figuered it was something like that. I even went to the types. py and found this.
S7AreaPE = 0x81 S7AreaPA = 0x82 S7AreaMK = 0x83 S7AreaDB = 0x84 S7AreaCT = 0x1C S7AreaTM = 0x1D

But I dont understand why Areas.PA, where did you find that info.

Thank you so much again.

[swamper123]

But I dont understand why Areas.PA, where did you find that info.

Because I am contributing to that repo for a while. 😉

If you go to the line in the repo:

python-snap7/snap7/client.py

Line 368 in 7aea4f6

def read_area(self, area: Areas, dbnumber: int, start: int, size: int) -> bytearray:

You will see, that the parameter has to be from Type "Areas" and "Areas" is located in snap7.types.

Since you made:

from snap7.types import *

You imported everything from snap7.types, the class Area as well. So you need to pass the right name of that.

The stuff you found in types S7AreaPE = 0x81 etc. is partly a leftover from older versions, where this has been used....

@lautarodapin are they still needed somewhere? I mean, that's what the Enum is for, isn't it?

[maxitaxi13]

Awsome, thank you :)