Problem Writing Attribute UINT Array

[davrm]

I used the example code "poll_example_many_with_write.py". I have modified this code to be able to communicate with my module. This is the code:

import logging
import random
import sys
import time
import threading
import traceback

import cpppo
#cpppo.log_cfg['level'] = logging.DETAIL
logging.basicConfig( **cpppo.log_cfg )

from cpppo.history import timestamp # requires 'pip install pytz'
from cpppo.server.enip import poll, client, enip_format
from cpppo.server.enip.ab import powerflex_750_series

address             = ("192.168.0.7", 44818)
targets             = {
     .5: ["Identity" , ('@4/0x64/3','UINT'), ('@4/0x65/3','UINT')],
}
timeout             = .5
values              = {} # { <parameter>: (<timer>, <value>), ... }
failed              = [] # [ (<timer>, <exc>), ... ]

# Capture a timestamp with each event
def failure( exc ):
    failed.append( (cpppo.timer(),str(exc)) )

def process( p, v ):
    values[p]           = (cpppo.timer(),v)
process.done            = False

poller              = []
via             = powerflex_750_series(
    host=address[0], port=address[1], timeout=timeout )

for cycle,params in targets.items():
    poller             += [ threading.Thread( target=poll.run, kwargs={
        'via':      via,
        'cycle':    cycle,
        'process':  process,
        'failure':  failure,
        'params':   params,
    })]
    poller[-1].start()

# Monitor the values and failed containers (updated in another Thread)
try:
    while True:
        while values:
            par,(tmr,val)   = values.popitem()
            print( "%s: %-32s == %r" % ( timestamp( tmr ), par, val ))
        while failed:
            tmr,exc     = failed.pop( 0 )
            print( "%s: %s" %( timestamp( tmr ), exc ))
        time.sleep( 1 )

        try:
            param       = "@4/0x64/3=(UINT)0,0,0,0,0,0,0,0,0"
            with via: # establish gateway, detects Exception (closing gateway)
                val,        = via.write( via.parameter_substitution( param ), checking=True )
                print( "%s: %-32s == %s" % ( timestamp(), param, val))
        except Exception as exc:
            logging.detail( "Exception writing Parameter: %s, %s", exc, traceback.format_exc() )
            failure( exc )
finally:
    process.done        = True
    for p in poller:
        p.join()

This it is the output from the code:

2018-07-17 08:32:49.046: ('@4/0x65/3', 'UINT')            == [0, 5801]
2018-07-17 08:32:49.046: ('@4/0x64/3', 'UINT')            == [0, 0, 0, 0, 0, 0, 0, 0, 0]
2018-07-17 08:32:49.046: Identity                         == [894, 43, 59, 257, 52, -1023340580, u'Acromag XT1542-xxx']
2018-07-17 08:32:49.102: read failed to access 1 attributes: @4/0x64/3=(UINT)0,0,0,0,0,0,0,0,0: status 8

I would like to know what I am doing wrong when writing in the attribute "@4/0x64/3" , since the readings work correctly.