Four relay outputs on a 20 mm slice
The Siemens 6ES7132-6MD00-0BB1 is a 4-channel relay output module for the ET 200SP distributed I/O system. It switches 24 V DC loads at up to 20 A total per module (derated to 16 A above 40 °C), which means a single slice can handle a bank of solenoid valves or small contactors without needing a separate interposing relay panel. The module occupies 20 mm on the DIN rail and mates with BU type B0 (3-wire) or (2-wire) base units. The 58 mm depth fits standard 80 mm enclosures with room for wiring ducts.
Current derating and thermal budget
The 20 A maximum at 40 °C drops to 16 A at both 50 °C and 60 °C, a flat derating step rather than a continuous curve. In a crowded cabinet with multiple output modules side by side, the 1.5 W typical power loss per module adds up — budget for 6 W on a 4-slice group before the ambient rise eats into the derating headroom. Each relay output requires a minimum switching current of 100 mA at 5 V DC to reliably wet the contacts. Below that threshold, use a resistive pre-load or switch to a solid-state output module.
Diagnostics and commissioning
Diagnostic alarm and group error reporting are built in, with a green/red DIAG LED per module and a green channel-status LED per output. No per-channel diagnostics — fault isolation requires checking the group error bit in the process image. The module supports automatic encoding of the base unit, so the hardware configuration is read back during startup. HW functional status from FS03 ensures consistent behaviour across firmware revisions.