How to pass a variable to and from PCDMIS using Python?

I don't normally use python, so if I get some particular wrong, you'll have to excuse me. The reason it doesn't work is because you are treating an object as a string. The dmispart.GetVariableValue function returns an object of type variable. You have to define an object for that, e.g., dmisvar = dmispart.GetVariableValue("SHORTLOT"). Then you use that object's properties to get or set the value.

import win32com.client as w32

dmisapp = w32.Dispatch("PCDLRN.Application")
dmispart = dmisapp.ActivePartProgram
dmisvar = dmispart.GetVariableValue("SHORTLOT")

short_lot_value = dmisvar.StringValue
# OR
dmisvar.StringValue = "LOT-123456"

Dismas121 

Thanks for the reply. I'll give that a shot. in the coming weeks and report back how it is working. Here is the code I'm going to try to pass back a variable to PCDMIS from python.

import win32com.client as w32

# Connect to PCDMIS
dmisapp = w32.Dispatch('PCDLRN.Application')
dmispart = dmisapp.ActivePartProgram
dmisvar = dmispart.GetVariableValue("SHORTLOT")

dmisvar.StringValue = "LOT-123456"

dmispart.SetVariableValue("SHORTLOT", dmisvar.StringValue)

Dismas121 

Thanks for the reply. I'll give that a shot. in the coming weeks and report back how it is working. Here is the code I'm going to try to pass back a variable to PCDMIS from python.

import win32com.client as w32

# Connect to PCDMIS
dmisapp = w32.Dispatch('PCDLRN.Application')
dmispart = dmisapp.ActivePartProgram
dmisvar = dmispart.GetVariableValue("SHORTLOT")

dmisvar.StringValue = "LOT-123456"

dmispart.SetVariableValue("SHORTLOT", dmisvar.StringValue)

I think the SetVariableValue second argument has to be of an object type Variable. So, you'll have to leave off the ".StringValue" part of your argument and just pass "dmisvar". Setting the StringValue in line 8 is sufficient.

I had to create a python program to sort some csv data so I dug back into this issue. 

You are correct that leaving off the .StringValue will cause the program to not error out, but for some reason it will not alter the variable inside of pcdmis. So where I am at now is I can get a variable from pcdmis, but I cannot pass a variable back into pcdmis for some reason.

The code function is not working right now so here is the python code with error logging so you can see what is happening....

import win32com.client as w32
import logging
import winsound

# Set up logging
log_file = r'C:\user\error.log'
logging.basicConfig(filename=log_file, level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')

# Connect to PCDMIS
dmisapp = w32.Dispatch('PCDLRN.Application')
dmispart = dmisapp.ActivePartProgram
dmisvar = dmispart.GetVariableValue("V2") # get variable from pcdmis

logging.info(f'The variable V2 from pcdmis is: {dmisvar.StringValue} ')  # success

dmisvar.StringValue = dmisvar.StringValue + "_LOT-123456"

logging.info(f'The modified variable is: {dmisvar.StringValue} ') # success

try:
    dmispart.SetVariableValue("V2", dmisvar) # pass variable to pcdmis
except Exception as e:
    logging.info(f'Error passing variable V2 to pcdmis: {e}')  # not kicking out an error msg

winsound.Beep(500,500)

If your line of code containing the variable has not been executed yet, you will get errors when executing scripts. I have had this happen to me many times after opening up a program the next day working on a script, and the GetVariableValue gives an object reference error. After executing said variable the error stops. This may not be your issue, but just in case I thought I'd mention it.

I am not too experienced with Python, but if your V2 original variable is a type of string, and you want the strings to append together, you will need to add quotes around the value here "_LOT-123456". I am not sure how you do it in python, but it essentially won't be able to concatenate within PC-DMIS into an assign statement without the quotes. 

It would just become ASSIGN/V2="YourV2Variable" + _LOT-123456

It needs to be ASSIGN/V2="YourV2Variable" + "_LOT-123456"
which will cause an error I believe. I feel it would still allow you to pass this variable back in though, because I can pass back a variable without proper quotes around my string in basic script within PC-DMIS.

You can use an alternative method to the GetVariableValue() and SetVariableValue().

GetText(DEST_EXPR, 0) --> Gets Variable "ID" or name

PutText(dmisvar, SRC_EXPR, 0) --> Sets variable's value

Example below in Basic Script for modifying the variable value of "V2"

Sub Main()

    Dim DmisApp As Object
    Dim DmisCmds As Object
    Dim DmisCmd As Object
    Dim DmisPart As Object    
    Dim DmisVar As String

    Set DmisApp = CreateObject("PCDLRN.Application")
    Set DmisPart = DmisApp.ActivePartProgram
    Set DmisCmds = DmisPart.Commands

    For Each DmisCmd In DmisCmds
        If DmisCmd.GetText(DEST_EXPR, 0) = "V2" Then
        DmisVar = DmisCmd.GetText(SRC_EXPR, 0) & "+" & """" & "_LOT-123456" & """"
        retval =  DmisCmd.PutText(DmisVar, SRC_EXPR, 0)
        End If
    Next DmisCmd
    
    Set DmisCmd = Nothing
    Set DmisCmds = Nothing
    Set DmisPart = Nothing
    Set DmisApp = Nothing
End Sub

In the mean time, I looked into how to convert/translate this into a Python script. I tested this and it works for me.

import win32com.client as w32

DmisApp = w32.Dispatch('PCDLRN.Application')
DmisPart = DmisApp.ActivePartProgram
DmisCmds = DmisPart.Commands

for DmisCmd in DmisCmds:
    if DmisCmd.GetText(133, 0) == "V2":
        DmisVar = DmisCmd.GetText(134, 0)+' + "_LOT-123456"' 
        retval = DmisCmd.PutText(DmisVar, 134, 0)

Best to avoid the variable object unless you need it.

import win32com.client as w32
import win32api
import ctypes

# CONSTANTS
DEST_EXPR = 133
SRC_EXPR = 134

dmisapp = w32.DispatchEx('PCDLRN.Application.14.2') # 14.2 = 2019 R2, 19.1 = 2024 R1
dmispart = dmisapp.ActivePartProgram
dmiscommands = dmispart.Commands

for command in dmiscommands:
if (command.Type==195):
if (command.GetText(DEST_EXPR, 0)=="V2"):
print(command.GetText(SRC_EXPR, 0)) # Current Value
command.PutText(chr(34) + "NewValue" + chr(34), SRC_EXPR, 0) # New Value
dmispart.RefreshPart

dmisapp.Quit