The 6ES7720-5AC42-0YC0 is a Siemens PG 720 P150 programming device — a ruggedized industrial portable computer used for commissioning, programming, and diagnostics on Siemens automation systems, equipped with a 2.1 GB hard drive and five expansion slots.
For sourcing, this part is available through surplus and broker channels. Verify hard drive condition and battery health before commissioning into a production line.
What the description tells a field technician
The description reads "PG 720 P,P150, 2,1 GB HD,5spr." — translating to a PG 720 with a Pentium P150 CPU, a 2.1 GB hard drive, and five expansion slots. This is a Windows-based device (typically Windows 95 or NT 4.0) used with STEP 7 V5.x for S7-300/400 programming. The 2.1 GB hard drive is small by modern standards; expect to work with a limited project archive. The 5-slot expansion is the key differentiator from the base PG 720 — it allows multiple fieldbus cards (CP 5511/5512) to be installed simultaneously.