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8
Advanced operation
8.1
Encoder communications
A communication channel is provided to allow the user to communicate with an encoder connected
to one of the communications interfaces (this feature is enabled using 1x.067 or 2x.067). During
auto-configuration of the position feedback device or during the transfer of electronic nameplate
data, the communications channel will be disabled.
To send a message to the encoder the required message must be written to the transmit register
(1x.068 or 2x.068). To read the response from the encoder, the data is read from the receive
register (1x.069 or 2x.069). The data is written one byte at a time and then stored in a 16 byte
buffer before being sent to the encoder. The data should only be written to the transmit register
when it has been cleared to zero by the drive. Bits 13 to 15 are used to control the interface.
Bit
This bit should be set to one each time data is written to the transmit register. This indicates
15
that data has been written. This bit will be cleared when the LS byte of the data has been
transferred into the comms buffer.
This bit should be set when the last byte of the message is written to the transmit register.
14
The data will be read and transferred to the comms buffer and then the message will be sent
to the encoder.
This bit should be set when the first byte of the message is written to the transmit register.
13
Setting this bit will reset the pointer to the start of the comms buffer.
Data can be read from the receive register at any time. If there is data in the buffer, bit 15 will be set.
Once the data has been read the register should be cleared and the drive will transfer the next byte
of data to the register.
Bit
15 Indicates that data from the last transfer can be read from the receive register.
14 Indicates that the last byte from the receive message is in the register.
There is no data in the receive buffer and the LS byte of the receive register is the comms
system status. If there was an error in the received message this will always be set and one
13
of the status error bits will be set until the comms is used again by this system or by the
drive.
The status flags are defined as follows:
Bit
The number of bytes put into the transmit buffer is not consistent with the expected message
0
length. (Hiperface only).
The number of bytes written to the transmit buffer, or the expected length of the store data
1
transmit message, or the expected length of a read data message have exceed the length of
the buffer. (Hiperface only)
2
The command code is not supported.
3
A valid response was not received from the encoder.
SI-Universal Encoder User Guide
Issue: 2
1x.068 or 2x.068 Function
1x.069 or 2x.069 Function
1x.069 or 2x.069 Function
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