TB521-ETH expands the AC500 V2 terminal-base arrangement to two communication-module positions beside one processor position. The Ethernet version provides the RJ45 network connection required by the matching Ethernet processor family.

Controller supply, serial interfaces, FieldBusPlug access and the local I/O bus are presented at the base so the installed CPU and communication modules can form one mechanically integrated station.

The terminal base is the physical carrier and interface breakout for the AC500 processor station. Its second communication-module position distinguishes it from TB511-ETH and supports controller arrangements needing two base-mounted communication modules.

The right-side I/O-bus connection extends the local station to S500 terminal units. The actual network and protocol behavior depends on the processor and communication modules installed on the base.

• Use an Ethernet AC500 processor whose order-code revision is approved for the R0270 terminal-base generation.
• PM57x-ETH, PM58x-ETH and PM59x-ETH processors with R0271 endings are paired with TB5x1-ETH bases using R0270 endings.
• TB521-ETH-XC is a separate extended-condition version and must be selected together with compatible XC system components.
• PM591-2ETH is assigned to TB523-2ETH rather than TB521-ETH.
• The number and type of communication modules must remain within the two available communication positions.

• AC500 V2 controller stations that need two communication modules beside the CPU.
• Ethernet-connected control panels using an RJ45 processor-network interface.
• Local S500 I/O expansion from the processor terminal base.
• Stations combining serial or FieldBusPlug functions with two communication-module slots.
• Maintenance replacement after the installed processor, modules and base revision are verified.