Processor board

The processor board is the main component of the controller. The board contains an ESP32 processor, a real-time clock, two analog inputs, two digital outputs, a temperature sensor, a watchdog safety circuit, an information RGB LED, DC-DC converters, and terminal blocks. The board can be expanded with an optional RS485 or LAN communication port. Analog input AO2 and both analog outputs are galvanically isolated.

	Watchdog
	A watchdog safety circuit checks the processor function and the voltage on the processor board. In case of low voltage or an inactive processor, it resets the entire board.

	Processor
	The controller contains a dual-core 32-bit processor with a frequency of 240 MHz. It also integrates 16GB of flash memory, which is used for both firmware and data storage.

	Clock
	The real-time clock accuracy is provided by high quality crystal. It can be adjusted to achieve maximum inaccuracy at steady temperature 37 seconds per year (1 ppm).

	Backup battery
	The controller contains one CR2032 battery as standard, two CR2032 batteries in the PRO version. The lifetime stated by the manufacturer is at least 10 years, but the real one is twice as long.

	LAN module
	There is a free slot for a LAN expansion module. This module cannot be combined with the RS485 communication output; it is necessary to select only one variant.

RGB LED

This glowing RGB diode provides information about the following states:

slowly blue flashes - the controller is in idle state

fast blue flashing - the controller is in delayed start mode

fast green flashes - the program is running, regulation is in progress

fast red flashes - the program is suspended or an error has occurred

	AD converter
	The high-precision 22-bit AD converter MCP3550 with integrated noise reduction and a sample frequency of 12.5 Hz. Each analog input has its own converter.

	Temperature sensor
	Very accurate temperature sensor MCP9804 is used for temperature measurement at the end of the thermocouple or compensation line.

Order codes:

CL5-CPUN - version without communication interface (8-pin terminal block)
CL5-CPUR - version with RS-485 communication interface (12-pin terminal block)
CL5-CPUL - version with LAN (Ethernet) module (8-pin terminal block + RJ45)