Power Supply - Logic IO RTCU MX2 turbo Technical Manual

RTCU MX2 turbo Technical Manual V2.04

Power supply

The RTCU MX2 turbo device must be supplied with 8..36 VDC from an external DC power source
connected to the X1 connector. Positive power is applied to the SUPP pin, and ground is connected
to the PGND pin.
The connector has two "SUPP" supply pins as these also supplies power to the digital outputs. If
the total current consumption on the digital outputs exceeds 5A, then power must be applied to
both pins. Otherwise one pin is sufficient.
There are three different labels for the ground connections:
•
Power Ground (PGND)
•
Signal Ground (SGND)
•
Analog Ground (AGND)
The signal and analog grounds are filtered from the power ground. Power ground must only be
used as power supply return path. The signal ground is used as ground reference for digital I/O's
and serial interfaces, and the analog ground is used as a low noise analog ground reference for the
analog inputs.
The RTCU is protected against wrong polarity. If a chassis or system ground is connected to either
SGND or AGND, a wrong polarity on the supply lines will destroy the internal GND connection.
For avoidance of such a scenario, a fuse can be installed on the positive supply.
The RTCU also contains an internal high capacity backup battery which will supply the RTCU if
the external power supply fails or is disconnected. By default, the RTCU is powered down when a
power fail occurs. This setting, however, can be changed. Please consult the RTCU IDE on-line
help for more information. The display will automatically turn off when external power is
removed.
Disabling the external DC power from the application interface and forcing the device to operate
on the internal backup battery is supported. Please consult the RTCU IDE documentation for
additional information.
When the ignition input is activated with a logical high, the RTCU unit will wake-up if it was in
power down mode. The ignition input (digital input 5) is available on the power connector to
minimize the need for connectors in minimal installations, but it is also available on the X3
connector (digital I/O and analog Inputs) - only one should be used at a time.
X1: 4 pin PWR connector overview
Pin Name
1 SUPP
2 DI5/IGN
3 SUPP
4 PGND
Logic IO ApS.
Holmboes Allé 14
8700 Horsens
Denmark
Description
Power supply, positive (+) connection
Digital input 5 / Ignition input (Shared with X3)
Power supply, positive (+) connection
Power Ground
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