cui.com

date 06/29/2018

│ page 3 of 10

CUI Inc

│ SERIES: AMT21 │ DESCRIPTION: MODULAR ABSOLUTE ENCODER

RS485 INTERFACE (CONTINUED)

Set Zero Position (Single-Turn Encoders Only)

Hex command sequence: 0x35 0xA5 0x7E

Set Zero Position

Figure 2

Command

START 0123456

7

STOP

0x35 0xA5 0x7E Sequence for SettingZero Position

7

6

5

4

3

2

1

0

START

START 0123456

7 STOP

STOP

The encoder will not give a response but will store the zero position, and then restart. This operation takes approximately

200 ms.

Read Turns Counter (Multi-Turn Encoders Only)

Command char: U

Hex command sequence: 0x55

Read Turns Counter

START

H3 H4 H5 K0 K1 STOP

0xFF low byte response

0x3F high byte response

L3

L2

L1

L0

L4

L5

L6

L7

STOP START H0 H1 H2

7 STOP

0x55 Read Turns Counter

Response

Command

START

0

1

2

3

4

5

6

The turns counter is stored as a 14-bit signed number. The encoder responds with two bytes using the same checkbit

formula as is used for position. After removing the check bits K0 and K1 the resulting value is still 0x3FFF. Since this is a

signed number the resulting turns counter value is -1. The turns counter is always zero at startup, a battery backup may

be required to prevent loss of turns count.

Read Position and Turns (Multi-Turn Encoders Only)

Command char: V

Hex command sequence: 0x56

Read Position and Turns

The encoder responds with the position response in the same format as is received by the 0x54 position command,

immediately followed by the turns counter in the same format as the 0x56 turns command.

Figure 3

Figure 4

For more information, please visit the product page.