Posted 3 Sep 2018 (edited) Hello, I am using Omron CP-1E PLC and expansion module 16ER and tc module. When plc operated alone it goes to run mode when expansion module is connected either 16ER or TC module plc ALM/ERR led turned on. Edited 3 Sep 2018 by MZohaib92 Share this post Link to post Share on other sites
Posted 3 Sep 2018 What model do you have? Some of them are not expandable: 1 person likes this Share this post Link to post Share on other sites