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Software Interface

Host Initiated Commands

3. Query Commands

Host uses query command to query data from the Engine. The maximum delay of the

Engine’s reply is 500 ms.

3.1 The Query Command Format:

The format of query Command Format:

Command Prefix Lens Data1 LRC

0x7E 0x00 Len Hi Len Low Data 1 …. Data N LRC

Where:

Command Prefix – A two-byte prefix field. Always 0x7E, 0x00.

Lens –

A two-byte length field. The total number of bytes in Data Type field and

Data1field.

Len Hi is the high (most significant) byte of the Lens field. Len Low is the

low byte of the field.

Data1 –

Command dependent Data1 field. Maximum size is 32 bytes.

LRC –

A one-byte LRC field.

LRC = 0xFF xor Len Hi xor Len Low xor Type xor Data1.

3.2. The Query Reply Format:

Reply Prefix Lens Data Type Data1 LRC

0x02 0x00 Len Hi Len Low 0x34 Data 1 …. Data N LRC

Where:

Reply Prefix – A two-byte prefix field. Always 0x02, 0x00.

Lens –

A two-byte length field. The total number of bytes in Data Type field and

Data1field.

Len Hi is the high (most significant) byte of the Lens field. Len Low is the

low byte of the field.

Data Type – Always 0x34 for reply.

Data1 – Command dependable Data1 field. Maximum size 32 bytes.

LRC – A one-byte LRC field.

LRC = 0xFF xor Len Hi xor Len Low xor Type xor Data1.

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Newland EM3000 Spezifikationen Seite 37