BK Precision 1785B - Page 23

23
4. 4
th
to 25
th
bytes are information content
5. 26
th
byte is check sum, the sum of the former 25 bytes.
Command Details:
In the following sections, we abbreviate the details of the commands. Since the first
three bytes of a command are i) the constant 0xAA, ii) the instrument address, and iii) the
command, we will not show those for each command. In addition, the 26th byte, the
checksum, will also not be shown.
The table includes a column for Byte offset. This is the zero-based index of the byte in
the packet. Note the offset numbers are in decimal.
A table entry of “Reserved” means the data are currently unused or reserved for future
use. Good programming practice is to set these bytes to 0x00.
Some commands require two byte and four byte integers to represent parameter
settings. These integers are stored in the command packet in little-endian format.
Little-endian is a byte ordering format in which bytes with lower addresses have lower
significance. We will refer to the individual bytes as follows:
For a two byte integer, the least significant byte will be called the low byte and the most
significant byte will be called the high byte.
For a four byte integer, we will use the following notation:
Least significant two bytes, least significant byte
Least significant two bytes, most significant byte
Most significant two bytes, least significant byte
Most significant two bytes, most significant byte
As an example, for the integer 0x23A749F5, we’d have
1
st
byte: 0xF5 Lower low byte
2
nd
byte: 0x49 Lower high byte
3
rd
byte: 0xA7 Higher low byte
4
th
byte: 0x23 Higher high byte
Lower low byte
Note:
You must change the power supply to remote control mode first, then you can control
the power supply output by computer. The command for remote control is 0x20.
If you want to calibrate the power supply, set the calibration information. If you want
to set the product serial number, you must set the calibration protection mode to OFF
state first. The command for calibration protection is 0x27. When the power supply
is in calibration mode, changes for the output state of power supply are not allowed.