1. Products from Shanghai Zhenghang, compatible with Siemens S7-200

www.zhenghangPLC.com

The quality is okay and the service is good. The price is about RMB 60~70 of Siemens

It has CPU and

module

interface

fully compatible and can be mixed with Siemens .

2. Shenzhen Ouchen's only has expansion modules, which can be connected behind Siemens CPUs. The quality is good, but the appearance is not the same as the Siemens ones. The price is about 70~80 from Siemens

I recommend Shanghai Zhenghang. None of your original stuff (programs, wiring, etc.) needs to be changed. Let

manufacturers

don't use trademarks. To some customers who don't understand

they can sell them as Siemens.