BruControl MEGA Format UniShield
This is a MEGA format interface shield, which accommodates interfaces such as the Arduino MEGA, AdaFruit Grand Central, other compatible MEGA format interface microcontrollers. It is a stacked design, containing a base board for I/O and a riser board for the interface. These are connected by ribbon cable, allowing for native shields to be used on top. It also contains an on-board 3 amp DC-DC buck converter to reduce the need for multiple power supplies on the control panel. The buck converter can be powered with 12 or 24 VDC and its output is adjustable from 3 to 12 VDC. It’s output can be switched to either supply the interface via its VIN pin (for example 6 – 9 VDC), supply the 5V pin directly (thereby bypassing the interface’s 5 V regulator to prevent an overheating regulator), or to supply an on-board terminal, creating a discrete DC-DC converter which can be used for other devices such as flow-meters, RTD-amplifiers, etc.
The base board contains 48 high-current outputs which are split into four banks, enabling each bank to be powered by different sources (e.g. 5, 12, 24 VDC). The current outputs limits are: 2.5 amps per output, 6 amps per driver (4 outputs each), 12 amps per bank (4 banks). This will eliminate the need for electro-mechanical relays to switch low-current DC. Therefore, contactors, valves, relays, DC pumps can be powered directly. This should reduce panel space and simplify wiring, reducing panel size and overall cost. PWM functions at up to 1000 Hz, enabling a DC pump without any additional hardware. The output drivers are fault tolerant – for example, will not be damaged by an accidental short-circuit.
Each I/O terminal set includes a high-current driver output and a “direct” pin, allowing for digital inputs. Fly-back diodes are included on driver outputs to damp inductive loads such as solenoids and relays, and reduce potential electrical noise. Drivers are enabled by default, but switches are included for all driver outputs to disable them.
The UniShield includes on-board pull-up resistors for I2C and 1-wire, so external devices such as 1-wire temperature sensors can be wired directly. It also contains terminals for power, analog inputs, SPI, I2C, AREF, grounds, and includes an extra reset button. The unit includes a DIN carrier for universal mounting.
The UniShield includes either an Arduino MEGA-2560 compatible interface or an AdaFruit Grand Central M4 (depending on the model), and has the current-version firmware loaded. Ethernet or Wi-Fi shields are also available options.
Read the UM-1 Product Note for more details, configuration, and installation. Please note that the Arduino MEGA interface is 5V compatible and the Grand Central is 3.3V compatible. These voltage compatibilities need to be taken into consideration during control panel design for any input pins (not applicable to high-current driver output pins).