SMA SIC 50 User Manual
Page 29
SMA Solar Technology AG
Electrical Connection
Installation Guide
SIC50-IA-en-11
29
Communication Protocol
The charge controller sends and receives data through the TXN bus and the RXD bus. The data is
coded in ASCII format.
Character Sequence of the Request
The character sequence of the request consists of 4 characters. The code letter and the device address
must be coded in ASCII format.
Character Sequence of the Response
The character sequence of the response consists of 14 characters. It begins with the control characters
13 and 10 (carriage return and line feed) They are followed by the code letter of the measured value
and the device address.
The following table shows an example for the character sequence of the response (device
SIC50-MPT 0 with operating voltage of +50.0 V):
Code Letter of the Measured Values
0
1
2
3
Control character 13
(carriage return)
Control character 10
(line feed)
Code letter
Device address
0
1
2
3
4
5
6
7
8
9
10
11
12
13
13
10
V
0
=
+
0
0
5
0
.
0
V
!
Code letter
Description
D
Temperature of the charge controller
E
Device fault (see section 11 ”Failure Search” (page 40))
I
Charging current
L
Charging threshold of the battery voltage
P
Charging power
S
Voltage at the PV array
T
Temperature of the battery
V
Operating voltage