DC Power Supply
【
DC-10-D/DC-20-D/DC-10-DH/DC-20-DH
】
6. SERIAL Communication
-47-
6-4 Communication Protocol
The following shows the step of communication transactions between power supply and HOST
computer.
HOST
Power Supply
メッセージ送信
メッセージ受信
ACK / NAK送信
ACK / NAK待ち
ACK / NAK受信
応答メッセージ送信
応答メッセージ待ち
応答メッセージ受信
ACK / NAK待ち
ACK / NAK送信
ACK / NAK受信
T0
T1
T2
T3
T4
Figure 6-5: Communication transaction step
T0: The state of waiting for ACK from the power supply after a message is sent from
HOST.
T1: Receipt of frames on the power supply side
T2: Receipt of ACK from the power supply
T3: Waiting for frames from the power supply
T4: Waiting for ACK from HOST after an acknowledgment message is sent on the power
supply side
①
Message sent on the HOST side
Message packets are sent from the HOST side to the power supply.
②
Receipt of message on the power supply side
After receiving message packets from the HOST side, the power supply reads the address
included in the massage to confirm that it is a message sent for itself. If the address is correct, the
power supply receives all messages and then judges the data length, message content, and
checksums. If the address is incorrect, the power supply does not respond to the HOST side but
clears the receive buffer and returns to the message waiting mode.
③
Sending ACK/NAK on the power supply side
After the judgment of received messages, the power supply sends ACK or NAK acknowledgments
to the HOST side.
ACK sends 0x06, or NAK sends 0x15.
ACK sends it when the received data is normal, whereas NAK sends it when the data is wrong.
After sending ACK/NAK, an acknowledgment message containing a 1byte command status
corresponding to the judgment result is sent.
④
Sending acknowledgment message on the power supply side
The power supply judges depending on the incoming message packets whether it is a Write
command or a Read command.
Message
transmitting
Message
receiving
ACK/NAK
transmitting
ACK/NAK
waiting
ACK/NAK
receiving
Acknowledgment
message waiting
Acknowledgment
message receiving
ACK/NAK
transmitting
Acknowledgment message
transmitting
ACK/NAK
waiting
ACK/NAK
receiving
Summary of Contents for DC-10-D
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