Siemens 6ES7288-1ST40-0AA1 SIMATIC S7-200 SMART CPU ST40 Controller

6ES7288-1ST40-0AA1 CPU ST40 increases the fixed I/O to 24 DI and 16 transistor outputs and raises total program/data memory to 40 KB. It is also wider at 125 mm, so confirm the panel cutout and DIN-rail space before replacing a 6ES7288-1ST30-0AA1 CPU ST30.

The onboard set includes 24 digital inputs at 24 V DC and 16 transistor outputs rated 0.5 A. This is useful when a machine needs more sensors and solenoids but should remain a single-CPU panel.

Provide 20.4–28.8 V DC with 24 V DC nominal operation. Siemens lists about 18 W power loss, dimensions of 125 × 100 × 81 mm and a weight of approximately 410 g.

6ES7288-1ST40-0AA1 CPU ST40 provides 40 KB total program and data memory. Buyers should estimate user-code size, recipe tables, retained variables, alarm history and communication buffers before freezing the hardware standard.

The 6ES7288-1ST40-0AA1 CPU ST40 combines PROFINET 10/100 Mbps with an integrated RS485 interface. A typical project can use PROFINET for the HMI or controller and RS485 for PPI, Modbus RTU, USS or free-port devices.

The onboard channels are 24 V DC transistor outputs, 0.5 A per point, not relay contacts. Check inrush current, common-group limits and suppression for inductive loads; use interposing relays when the field device exceeds the 6ES7288-1ST40-0AA1 CPU ST40 rating.

Provide 6ES7288-1ST40-0AA1, the existing CPU model, program size, DI/DO list, output load currents, expansion modules, PROFINET device names, RS485 protocol, quantity and destination.