Siemens has discontinued their 353 SLC controller. The 353 was used in many process applications for many years. It's discontinuation leaves many companies without an alternative.
Don't worry - you don't have to turn to eBay looking for spare parts? There's a better solution - the Yokogawa YS1700 PID loop controller. The YS1700 is a drop-in SLC replacement for the Siemens 353 and will keep you off of eBay.
The YS1700’s powerful function block programming allows for custom strategies to control many demanding processes such as boilers and steam generators, PH control, dosing control, and many other demanding plant processes. For more information, visit this site.