DC Power Supply
【
DC-10-D/DC-20-D/DC-10-DH/DC-20-DH
】
6. SERIAL Communication
-49-
An example of data transmission/reception is shown below.
○
Example of transmission/reception of Write command
When 20kW is sent to the power supply by Command 0x12 (the LEVEL HI-RES signal setting):
When the Address of the power supply is set to 1:
As an example of transmission and reception, data are transmitted and received between the
HOST side and the power supply side as follows:
①
HOST side:
81 02 58 20 4E B5 (Data field: little endian)
②
Power supply side:
06 or 15
③
Power supply side:
81 00 00 81 (When NAC [15] is received: 81 00 02 83 etc.)
④
HOST side:
06
①
The command is sent from the HOST side as follows:
Six bytes of 81 02 58 20 4E B5 are sent.
81:
SOF + Address (1)
➡
10000001 is sent.
02:
When the command data length is 0x58, 0x02 is sent since the data is 2byte long.
58:
Command (LEVEL HI-RES signal setting)
20 4E: For the command data, 00100000 01001110 (0x20, 0x4E) (20000) is sent.
* The data field is little endian.
B5:
The checksum is a value calculated with XOR for packets other than the checksum.
②
After receiving the command, the power supply sends ACK (0x06) or NAK (0x15).
③
After sending ACK (0x06) or NAK (0x15), the power supply continuously sends the command
status.
When the command has been correctly received
The power supply sends ACK (0x06) and then an acknowledgment message containing the
command status.
The acknowledgment message is as follows:
81 00 00 81
81: SOF + Address (1)
➡
10000001 is sent.
00: As the command data length is the command status only, 0x00 is sent.
00: As the command status has correctly received the command, 0x00 is sent.
81: The checksum is a value calculated with XOR for packets other than the checksum.
When the received command is incorrect
(Sending a value higher than 20kW by Command 0x58 (LEVEL HI-RES signal) for a 20kW
system etc.)
The power supply sends ACK (0x06) and NAK (0x15), and then an acknowledgment message
containing the command status.
In this case, the command status is a value other than 0.
The acknowledgment message is as follows:
81 00 02 83
81: SOF + Address (1)
➡
10000001 is sent.
00: As the command data length is the command status only, 0x00 is sent.
02: As the command status is out of the command setting range, 0x02 is sent.
83: The checksum is a value calculated with XOR for packets other than the checksum.
④
After receiving an acknowledgment message from the power supply, the HOST side sends
ACK.
After receiving this ACK, the power supply goes into the waiting mode to receive the the next
command.
If no ACK is received, a timeout occurs in 4seconds and it is automatically put into the waiting
mode to receive the next command.
