Now that entire Moore/Siemens 350 family is obsolete, are you considering upgrading to a DCS?
Are you concerned about the cost and time for a new installation, application development and personnel training?Is it possible that the new equipment vendor may again leave you stranded with their equipment as their core business is not industrial automation and control?
We have a better solution for you: Yokogawa and its YS1700 PID loop controller. Yokogawa has been providing industrial solutions, as their primary business, for over a century and their YS1700 will keep you off of eBay looking for spare 353 parts.