6.0
6.3 Serial RS-232
The serial port connection on the GenStar MPPT is a standard 9-pin isolated RS-232 port. See
Figure 2-3 (#9) for the port location.The GenStar MPPT communicates through the serial port via
the open standard MODBUS
TM
protocol.
Connect the GenStar MPPT to the serial port for:
• Modbus RTU communications
• Controller firmware updates with MSLoad
TM
firmware utility.
LiveView Update page is
recommended for faster uploads.
NOTE:
The RS-232 and EIA-485 ports share hardware. Both ports cannot be used
simultaneously.
Figure 6-1. A serial connection between a PC and the GenStar MPPT
Default Serial Port Settings:
• 9600 Baud rate
• 8 data bits
• 1 or 2 stop bits
• no parity
Serial Cable
6.4 Modbus and ModbusIP via EIA-485
An EIA-485 Bus System allows monitoring of multiple GenStar units using the GenStar MPPT
EIA-485 terminals to set up a 3-wire bus to connect GenStar units. The unit used for monitoring
must have, "Bridging", enabled in either its local meter or in LiveView.
EIA-485 WIRING
The EIA-485 port has three (3) connections: Power, Data A, Data B. Data A & B are differentially
driven data lines that carry the network data. The GenStar MPPT supplies isolated power to the EIA-
485 network, eliminating the need for an external bus power sources in many cases.
Connect Data A, B and GND wires to GenStar EIA-485 terminals. Connect Data A, B and GND wires
to a desired bus-connected controller, e.g., another GenStar. NOTE: If a desired bus-connected
(EIA-485 compatible) controller is not a GenStar, a voltage supply will need to be provided to the
bus at the connected controller.
NOTE:
The RS-232 and EIA-485 ports share hardware. Both ports cannot be used
simultaneously.
EIA-485 is a networking standard for serial communication between multiple devices on a bus. The
GenStar MPPT communicates over an EIA-485 network via the open standard MODBUS
TM
protocol.
Use EIA-485 networking to:
• Facilitate Modbus communications between GenStar MPPT controllers and other Modbus
devices
• Bridge an Ethernet connection through a GenStar MPPT to an EIA-485 network
Networks requiring more power can be supplied by an external source. The source voltage must
be between 8-16 Vdc. For 12 Volt systems, the network can be powered directly from the system
battery. Use a DC-DC converter for 24, 36, and 48 Volt systems.
CAUTION: Equipment Damage
Tapping power off of individual batteries in a series string of batteries can cause a
voltage imbalance. Damage to the batteries may result. Always use a DC-DC converter
to power the EIA-485 network if the nominal system voltage is greater than 12 volts.
For more information on EIA-485 networking, refer to the, “Morningstar Communications
Document”, on our website at:
www.morningstarcorp.com
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GenStar MPPT
Networking and Communications
