Communications; Communication Procedures - Weidmuller Power Monitor Handbuch

Communications

9. Communications
9.1

Communication procedures

Communication starts with command transmission from the host computer (hereafter referred to as Master)
and ends with the response of Power Monitor (hereafter referred to as Slave).
Master
Command
Data
Command
Acknowledgement
Command
Negative
acknowledgement
Command
No response
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Slave
• Response with data
When the Master sends reading command, the Slave responds with the
corresponding set value or current status.
• Acknowledgement
When the Master sends setting command, the Slave responds by send-
ing the acknowledgement.
• Negative acknowledgement
When the Master sends a non-existent command or value out of the
setting range, the Slave returns a negative acknowledgement.
• No response
The Slave will not respond to the Master in the following cases:
• Global address "FF" (MEWTOCOL) is set
• Broadcast address "00H" (Modbus protocol) is set
• Communication error (framing error, parity error)
• CRC-16 discrepancy (Modbus RTU mode)
• CS discrepancy (DL/T645)
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