User manual

Dx34510b_oi_e.doc / Jun-15 Page 29 / 42
5.5.1. PC-Mode
Communication with PC - Mode allows free readout of all parameters and registers of the unit.
The subsequent example shows the details of communication for serial readout of the actual
display value.
This is the general format of a serial
request string :
EOT
AD1
AD2
C1
C2
ENQ
EOT = Control character (Hex 04)
AD1 = Unit address, High Byte
AD2 = Unit address, Low Byte
C1 = Register code, High Byte
C2 = Register code, Low Byte
ENQ = Control character (Hex 05)
Example: Request for the actual display value from unit number 11:
ASCII-Code:
EOT
1
1
:
1
ENQ
Hexadecimal:
04
31
31
3A
31
05
Binary:
0000 0100
0011 0001
0011 0001
0011 1010
0011 0001
0000 0101
Upon correct request the unit will respond
as shown on the right. Leading zeros will
be suppressed.
BCC represents a block check character
generated from an Exclusive-OR of all
characters from C1 through ETX
(inclusively)
STX
C1
C2
x x x x x x x
ETX
BCC
STX = Control character (Hex 02)
C1 = Register code, High Byte
C2 = Register code, Low Byte
x x x x x = Register data
ETX = Control character (Hex 03)
BCC = Block check character
With incorrect request strings, the unit only responds STX C1 C2 EOT or just NAK.
Provided the actual display value of the unit would be "-180" (example), the full response of the
unit would be as shown below:
ASCII
STX
:
1
-
1
8
0
ETX
BCC
Hex
02
3A
31
2D
31
38
30
03
1C
Binary
0000
0010
0011
1010
0011
0001
0010
1101
0011
0001
0011
1000
0011
0000
0000
0011
0001
1100
Again BCC represents the block check character formed from the Exclusive-OR of all characters
from C1 through ETX