SAME SKY | SERIES: AMT21 | DESCRIPTION: MODULAR ABSOLUTE ENCODER

date 09/12/2024 | page 4 of 10

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RS485 INTERFACE EXAMPLES

Single character commands

Read Position: <node_address>

The read position command is the same as the node address which has a default value of 0x54 is sent and the response is received with

the low byte first. After removing the checksum the result is 0x39E4. For a 14-bit encoder nothing else is required, the position is 14820

in decimal. However if this is a 12-bit encoder, the position must be shifted to the right 2 bits to throw away the low bits of the response.

Therefore the position would be 3705 in decimal.

Read Turns (multi-turn encoders only): <node_address + 0x01>

The turns counter command is <node_address + 0x01>. By default the turns counter command is 0x55. The encoder responds with the low

byte first and includes check bits same as the read position command. The resulting number is a signed 14 bit number. The response above

is showing 1 turn. This value is not retained between power cycles. After a power cycle, the value is reset to zero.

Extended commands

Set Zero Position (single turn encoders only): <node_address + 0x02> <0x5E>

The zero set command is <node_address + 0x02> followed by <0x5E>. By default we send 0x56 and then 0x5E. The encoder zero’s the

position and immediately resets.

Encoder Reset: <node_address + 0x02> <0x75>

The reset command is <node_address + 0x02> followed by <0x75>. By default the command to reset the encoder is 0x56 0x75. The

encoder performs and immediate reset.

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