Solar panel and battery combinations for a DXM Controller system
Solar Panel
Battery Capacity6
Days of Autonomy
DXM mA
DXM Controller
5 watt
10 Ahr
10 days
25 mA
DXM Slave Controller - ISM radio and I/O base board
20 watt
14 Ahr
10 days
30 mA
DXM Controller with ISM radio
20 watt
20 Ahr
10 days
35 mA
DXM Controller with ISM radio and Cellular Modem
6.3.4 Monitoring Solar Operation
The DXM solar controller provides Modbus registers that allow the user to monitor the state of the solar panel input
voltage, the battery voltage, the charging current, and the temperature in °C. The DXM Controller can be configured to
monitor the health of the charging system as well as send an alert message when the battery is too low.
The charts show a typical charging cycle, with each vertical grid representing about eight hours. The chart shows three
days of charging.
Figure 3. Solar Panel Voltage (mV) -- Cloudy First Day
Figure 4. Battery Voltage (mV) - Cloudy First Day
6.4 Connecting the Communication Pins
The base board communications connections to the DXM100-B1 Wireless Controller are RS-485 (primary), RS-485
(secondary) or RS-232. The base board communications connections to the DXM100-B2 Wireless Controller are RS-485
(primary) and RS-485 (secondary).
RS-485. The primary RS-485 bus is a common bus shared with the ISM radio board (Modbus Slave ID 1) or optional
cellular board. The DXM100-Bx Wireless Controller is defined as the Modbus Master on this bus. Other internal Modbus
slaves include the local processor registers (Modbus Slave ID 199), the base I/O controller (Modbus Slave ID 200), and the
display board (Modbus Slave ID 201). When assigning Modbus Slave IDs to externally connected devices, only use IDs 2
through 198.
RS-232. The RS-232 bus is not currently defined for the DXM100-B1 models. There is no RS-232 for the DXM100-B2
models.
Pin
Parameter
Description
Pin 6
Primary RS-485 –
Running Modbus protocol at 19.2k baud, use this bus to connect to other Modbus Slave devices.
The DXM100-Bx Wireless Controller is a Modbus Master device on this RS-485 port.
Pin 7
Primary RS-485 +
6 Battery capacity (amp hour) is standard amp rating taken for 20 hours. Battery capacity should be monitored for reliable system power and may
need to be increased for cold weather locations.
DXM100-Bx Wireless Controller Instruction Manual
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