Product Description:

The X20CP3684 is a CPU module from B & R Automation that belongs to the X20 Fieldbus Input Output Modules series. Installed on an X20 backplane, the unit supplies central processing capability for distributed I/O nodes. It coordinates deterministic control tasks and fieldbus communication inside automated machines and production lines. This arrangement allows one compact module to handle local logic while exchanging data with surrounding station modules.

The module’s computing core runs at 400 MHz, a clock frequency that indicates how many instruction cycles can be handled each second. Its processor is the Intel-based Atom E3915, giving the controller x86 instruction set compatibility for the Automation Runtime environment. A dedicated Level-2 cache of 1 MB stores frequently used data close to the core to shorten memory access times, while main program variables reside in 512 MB of LPDDR4 SDRAM to support low-power operation. Application code and operating system images are saved to 1 GB of onboard eMMC flash, so they remain stored through power cycles and vibration. This memory arrangement supports local control programs, variable handling, and stored system files without requiring external storage media.

Execution performance is shown by an instruction period of 0.0044 µs, allowing rapid Boolean and arithmetic operations, and by a shortest task scheduler interval of 400 µs, which sets the minimum scan time for real-time control loops. The CPU and the internal X2X interface draw up to 36 W from the 24 V DC backplane supply. The housing has an IP20 rating, so the electronics require installation inside a protected enclosure to reduce exposure to dust and accidental contact. Additional resources include 512 kB of remanent variable space for retaining process data after shutdown, three modular interface slots for communication or mixed-signal expansion, and RS-232 links that can span up to 900 m for long-distance diagnostics in large facilities.