Lenze AC Tech ESVZAP0, Communications Interface Reference Manual

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29 CMVPFB01A
Acyclic Parameter Access
6.3.2 4WPA - Access Control and Status (Byte 1)
The purpose of the Access Control and Status Byte is to provide transfer control and diagnostic information
when an acyclic message fails. The Status bits provide diagnostics on the message currently being
processed.
Table 28: 4WPA Access Control and Status
Bit Description
0
0 = No fault, Write ACK 8 = Invalid value
1 = Invalid function 9 = Access failure
2 = Parameter does not exist 10 = Write operation failure
3 = Invalid subindex 11 = Reserved
4 = Read only parameter 12 = Reserved
5 = Network write disabled 13 = Reserved
6 = Value too high 14 = Reserved
7 = Value too low 15 = ACT unknown exception
1
2
3
4 1 = Valid response to the request message - bit set by module to indicate
the data in message is valid or acknowledgment for write access (it could be
negative if bit 7 of Byte 0 is set and the exception number is higher than 0).
5 1 = Module is processing the master's request. Any data being sent to the
master at this time is invalid.
6 Reserved
7 Toggle bit. (Handshake) Master toggles this bit to indicate a new message.
The old command (if not finished) is cancelled.
NOTE
Bits 0 to 6 are set by the module. Bit 7 is set by the master. The module matches the state
of bit 7 in its response message.
NOTE
1. Bit 7 of the Access & Status byte will cause the message to be executed when it changes state. Each time
this bit changes state it indicates a new request is being made. This bit must be set by the Master/PLC
once all other bytes have been set in the 4WPA message. Otherwise a partially assembled message will
be processed by the drive causing unexpected results.
2. The drive will copy the state of Bit 7 from the message sent by the master to Bit 7 in the response.
3. Bit 7 is set indicating a fault occurred. Fault information is contained in the Access Control & Status Byte
4. This drive had an external fault in the Fault 3 location (Fault History Example 3).
6.3.3 4WPA - Parameter Number (Bytes 2 & 3)
This is the drive parameter number to be Read or Written to from the master. For the reply message from
the drive this will contain the drive parameter number that message corresponds to. Byte 2 is the Most
Significant Byte (MSB) of the 16 Bit Parameter Number. Byte 3 is the Least Significant Byte (LSB).