Plc5 reading remote io

I have 2 slc5/05 plc 's connected over ethernet.
I am able to have one Plc read any word from the second successfully for example if I have Target device>data table address set to N11:0

If I try to read inputs or outputs however with data table address of O:0 I get a msg error.
"Target node cannot respond because target node denies access."

Am I doing this wrong or are inputs and outputs treated differently.

Thanks.

"O:0" is not a valid address. O:0.0 is. Its a 16 bit word holding addresses O:0.0/1 thru O:0.0/15.

FYI, I always buffer those addresses, move/copy them to an integer or binary word. ( prevents someone from trying to write to them)

Never try to write to those words (input/output words) as the receiving PLC will overwrite them depending on its logic. Just bad practice.

I'll give that a try.
Thanks.

O:0.0 didn't work.
When I put that in it accepts and assembles edit, however if I go back in and look at msg setup again the target address reverts to O:0

Post your program if you can. Its .RSS file ( zip it first)

What slot is the output module in O:0 would be the "0" slot which holds the PLC ( processor)

O:1.0 would be the first slot available for a output card.

I missed that in my first post post.

Mickey said:

Post your program if you can. Its .RSS file ( zip it first)

What slot is the output module in O:0 would be the "0" slot which holds the PLC ( processor)

O:1.0 would be the first slot available for a output card.

I missed that in my first post post.

Click to expand...

Give me 24hrs.
I'll post full details.
Thanks

The whole story

I was asked to put a hardware counter on a particular plc output for a starch making machine (Ringwood) to count how many batches are being made.

This machines plc is password protected by the supplier.

I thought it would be possible to setup a slc5/05 in the workshop and just read the state of the Ringwood plc ouput I wish to monitor every .5 seconds and log results on this workshop plc.

Problem 1 - memmory map doesn't match hardware:
The output I wish to monitor is shown in electrical drawings as O:07/06.
The rack configuration matches the electrical drawings with first 4 slots as input cards and next 3 slots as output cards. There is then a scanner but this only does weigh scale instruments.

https://drive.google.com/file/d/0ByZK7lGjg-zfaUR2WnBNR25XVGc/view?usp=sharing

When I look at the Ringwood plc webserver (I don't have plc password), the Output modules are shown starting at O:0 going to O:34. O:0, O:1, O:2 show data which corresponds to actual state of outputs at slot 5/6/7 which I don't understand.

https://drive.google.com/file/d/0ByZK7lGjg-zfcHN1VEo5cWdFZjQ/view?usp=sharing


Problem 2 - cant read Inputs or outputs:

When I set my program to read any B or N word I get the data
coppied to the workshop plc (top image).
If I try and read output O:0, O:2, o:6 ... I get the error (bottom image)

https://drive.google.com/file/d/0ByZK7lGjg-zfdjZHZ19sczdZWlk/view?usp=sharing


Most likely problem 1 is cause of problem 2.
Either way it's academic now as I have installed hardware timer.

my workshop plc program used for reading remote data can be found in following link.

https://drive.google.com/file/d/0ByZK7lGjg-zfTUtlbUdVX2lNb1U/view?usp=sharing
Any ideas?
I will edit post if I can get pics uploaded.
Thanks.

O:0 is not a valid address. (slot 0 is where the processor resides)

If you want to read the data from the output card in slot 7 use O:7.0 address.

Slot 5 is O:5.0
Slot 6 is O:6.0

Input cards use words...

Slot 1 I:1.0
Slot 2 I:2.0
Slot 3 I:3.0
Slot 4 I:4.0

The problem was MSG plc target device was set to PLC5 and should have been set to 500CPU.

Note having target device as plc5 works fine for everything except Inputs and Outputs.

I also discovered that the plc webserver displays memory map for Inputs and outputs incorrectly just to add to confusion.

All working now. Thanks.
Gavin.