DC Power Supply
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DC-10-D/DC-20-D/DC-10-DH/DC-20-DH
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6. SERIAL Communication
-48-
For a Write command:
An acknowledgment message containing a 1byte command status is sent to the HOST side.
* For details on the command status, refer to the command status in [Table 6-3].
For a Read command:
The requested data are collected and an acknowledgment message containing a 1byte
command field + data is sent.
For a Read command but in a case where the power supply sends NAK in Step (3):
An acknowledgment message containing a 1byte command status is sent to the HOST side.
* For details on the command status, refer to the command status in [Table 6-3].
Table 6-3: Overview of command status
Command status
Description
0x00 Command OK
This indicates that the command is correctly received.
0x01 Command Not OK
This indicates that the command is not defined.
0x02 Data Range NG
It indicates that the data is outside the selection range.
0x03 Check Sum ERROR
It indicates that the checksum value of the data is wrong.
0x05 Data Length NG
It indicates that there is an error in the length of the received
data.
⑤
Receipt of an acknowledgment message on the HOST side
The HOST side can judge the data it sent according to the acknowledgment message.
For a Write command:
If ACK is received and the command status of the acknowledgment message containing a 1-byte
command status is 0x00, it indicates that the power supply side has received the message
properly and the transmission/reception process is completed.
If NAK or ACK is received but the command status is not 0x00, the power supply has not
received correct data.
* In this case, check the content against the command status in [Table 6-3] to see if the
commands or data are incorrect, and then check the details against the command lists in
[Tables 6-4, Table 6-5].
For a Read command:
If ACK is received, it indicates that an acknowledgment message containing the command field
+ data is received and the transmission/reception process is completed.
If NAK is received the power supply has not received correct data.
* In this case, check the content against the command status in [Table 6-3] to see if the
commands or data are incorrect, and then check the details against the command lists in
[Tables 6-4, Table 6-5].
⑥
Sending ACK on the HOST side
For the HOST side, send ACK to the power supply after receiving an acknowledgment message
from the power supply.
⑦
Reception of ACK on the power supply side
The power supply returns to the waiting mode after receiving ACK and then shifts to the mode
where it can receive the next message.
If no ACK is received, the ACK waiting mode continues.
The ACK waiting mode automatically recovers approx. 4seconds after an acknowledgment
message is sent from the power supply side, and goes into the message waiting mode.
Summary of Contents for DC-10-D
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