SunSaver MPPT MODBUS Document

TriStar MPPT MODBUS Document v10
http://www.morningstarcorp.com 17/26 05 Dec 2011
time_eq_daily
[79][0x004E] (s). Cumulative time in Equalization today.
Reports the cumulative number of seconds the battery has been in the Equalization charge stage today.
Counter resets at night.
time_fl_daily
[80][0x004F] (s). Cumulative time in Float today.
Reports the cumulative number of seconds the battery has been in the Float charge stage today. Counter
resets at night.
Vb_ref_slave
[90][0x0059] (V). Battery regulation override
Write a voltage value to this register to override the battery regulation. This allows for system control of
1 or more controllers via Modbus. Writing a non-zero value to this register forces the controller into
“slave” state. The register value must be updated every 60 seconds or less, else the controller will fault.
Writing to the register after a timeout will exit fault state and resume operation.
Va_ref_fixed
[91][0x005A] (V). Array Voltage fixed target
Write a voltage value to this register to fix the Array input voltage to a specific value. If this register is a
non-zero value, the MPPT function of the controller will stop (sweeping and tracking are disabled) and
the array input will be fixed to the specified voltage. This value can be written at anytime during
operation to adjust the array voltage target value. On start-up, this value is initialized with the non-
volatile EEPROM value in register 0xE020.
Supported in processor A - V09 firmware and later.
Va_ref_fixed_pct
[92][0x005B] (%). Array Voltage percent of Voc voltage target
Write a value to this register to fix the Array input voltage to a percent of the Array open circuit voltage.
If this register is a non-zero value, the MPPT function of the controller will stop (sweeping and tracking
are disabled) and the array target voltage will be fixed to the specified % of array Voc. The controller
will perform periodic Voc checks and move the array voltage if needed to maintain the correct % target.
If this register value is changed, the array voltage will not adjust until the next Voc check.
On start-up, this value is initialized with the non-volatile EEPROM value in register 0xE021.
Supported in processor A - V09 firmware and later.
Note: if the Va_ref_fixed (0x005A) register is non-zero, it will override this setting.