Siemens Simatic S7-300, Counter Module Fm 350-1 For S7-300, Counter Functions Up To 500 Khz 6es7350-1ah03-0ae0,6es73501ah030ae0 - Instrument Parts & Accessories - AliExpress
Linear RVCTBD50 Rev Counter Board for FM350 FM352 FM500 FM502 FM600 2000XL | 123 Security Products