Appendix B - Impulse Advanced Programming

Write Requests

The following example illustrates a write request of zero to parameter index #113 (Commanded Position) to unit #1. Bytes are shown in hexadecimal format.

01 71 00 00 00 00 72 00

Checksum Upper Byte

Checksum Lower Byte (Address + Index + Data)

Cmd Position Upper Byte, Upper Word

Cmd Position Lower Byte, Upper Word

Cmd Position Upper Byte, Lower Word

Cmd Position Lower Byte, Lower Word

Parameter Index 113

Unit Address #1

After sending the write request, the host system would need to wait for the drive to respond before sending another read query or write request. The drive responds to a write with a standard frame of unit address, a parameter index of zero, data and checksum. A successful write response is as follows:

01 00 00 00 01 00

Checksum Upper Byte

Checksum Lower Byte (Address + Index + Data)

Transmission Status Upper Byte

Transmission Status Lower Byte

Parameter Index 113

Unit Address #1

A non-zero transmission status indicates an error has occurred. Interpreting the transmission status is covered in the next topic.

Interpreting the Transmission Status Response

Whenever an error occurs during a transmission received by the drive, the drive reports the error in the Transmission Status Response. Error response are defined as follows:

0

No Error

4

Receive Checksum Error

8

Invalid Parameter Data Field Length

B-3

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