Siemens Step 5
STEP 5 is the programming software for the programmable logic controllers Simatic S5 from Siemens. Siemens discontinued this software on October 1, 2005, as the Simatic S5 is no longer being developed. S5 is being followed-up by Simatic S7 with the STEP 7 programming software.
With STEP 5, user programs can be created for all Simatic S5 programmable controllers.