Experimental Physics and
Industrial Control System

"Schuh, Stephen" <[email protected]> · Tue, 5 Apr 2011 21:11:11 -0700

If you are talking about PLC data type REAL, the ether_ip readme advises a maximum array size of 40. For BOOL arrays the max recommended size is 350.

Excerpt from the readme:
"Arrays should be one-directional: Use separate "EPICS to PLC" and "PLC
to EPICS" arrays. Because of PLC buffer limitations, the array size is
unfortunately limited to about BOOL[350] and REAL[40]. While you can
define bigger arrays, those cannot be transferred over the network
with EtherIP. Consequently you might end up with several transfer arrays."
(See http://epics.hg.sourceforge.net/hgweb/epics/ether_ip/file/tip/ether_ipApp/doc/readme.txt)

-Stephen
________________________________________
From: [email protected] [[email protected]] On Behalf Of Stephen Lewis [[email protected]]
Sent: Tuesday, April 05, 2011 3:53 PM
To: [email protected]
Cc: Stephen Schuh; Maida, Ricardo E.
Subject: Ether/IP array limits

We are using ether-ip-R2-5 with Allen-Bradley ControlLogix PLCs and version 15 of the AB (Rockwell) ladder logic.  Our previous engineer limited the arrays that are used to block transmit and receive variables to and from EPICS to 32 elements.  Is there a limit or can they safely be expanded to 64 elements?  The soft IOCs are hosted on RedHat Linux 4, 32-bit, built against base 3.14.9.

--Steve

Stephen Lewis
[email protected]<mailto:[email protected]>

Linac Coherent Light Source
SLAC National Accelerator Lab
2575 Sand Hill Rd | M/S-10
Menlo Park, CA 94025

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System