SunSaver MPPT MODBUS Document

TriStar MPPT MODBUS Document v10
http://www.morningstarcorp.com 8/26 05 Dec 2011
Variables and Definitions
Variable_name
[Logical Address][PDU Address] (Units). Short description.
Definition.
Read Holding and Read Input Registers
Located in processor RAM, updated continuously.
V_PU hi, V_PU lo
[1,2][0x0000, 0x0001] (V). voltage scaling.
The scaling value for all voltages. The scaling value is defined as:
V
scaling
= whole.fraction = [V_PU hi].[V_PU lo]
Example:
V_PU hi = 0x004E = 78
V_PU lo = 0x03A6 = 934
V_PU lo must be shifted by 16 (divided by 2^16) and then added to V_PU hi
V
scaling
= 78 + 934/(2^16) = 78.01425
I_PU hi, I_PU lo
[3,4][0x0002, 0x0003] (V). current scaling.
The scaling value for all currents. The scaling value is defined as:
I
scaling
= whole.fraction = [I_PU hi].[I_PU lo]
See the V_PU scaling example above
ver_sw
[5][0x0004] (). Software version.
Firmware version for the controller. This is not the version number for the network software, which can
be found in the web page views. The value is stored in binary coded decimal (BCD) format. Decimal
version 12 is thus stored as 0x0012 not as 0x000c.