IRC5 Assembly Instance data size


I am working with an IRB4600 and an IRC5 that is communicating with a AllenBradley Safety PLC for transmission of various safety and non safety data.  When programming the assembly instances to communicate over Ethernet, you use instance "100" for the standard input data and instance "112" for the standard output data.  You then set 8 bytes for Input size and 8 bytes for Output size. 
My problem is, I used up all of my Output bits, but have found more information that I'd like to send to the IRC5.  Is it a simple matter of changing the size of the output bytes from 8 to 10 if I want to send 2 more bytes of data or is it more complicated (i.e. do I also have to change the assembly instance that is used and pick an instance that is appropriately sized?) {I also realize that any change made on the PLC side must be mirrored on the IRC5 side so there is not data loss/overrun etc}.


  • revans
    You can increase the amount. You just need to go into the configuration-IO/System-Ethernet/IP internal Device and change the values for you input and output bytes to whatever you want it to be. The max is something like 512 bytes I believe.

    You cannot increase safety bytes, so if you are using the Safemove module, that is capped at 8bytes, but that is separate from the regular communication bytes. Meaning you can have 100 standard input bytes, 16 standard output bytes and still have the 8safety input and output bytes.

    You will not need to change the assembly values on the PLC, but you will need to update the number of bytes.