Multi cycle SSI signal encoder

Product Series

BTM58-J

BTM58-K

BTM58-K2

BTM58-T

Size (shell)

Ø 60mm

Ø 60mm

Ø 60mm

Ø 60mm

feature

Axial belt clamping flange

Top thread blind hole type

Tightening ring blind hole type

Axial belt synchronous flange

Spindle size

Shaft type Ø 6, 8, 10, 12mm

Blind hole type Ø 6, 8, 10, 12, 14, 15, 16, 18, 20, 22mm

Shaft type Ø 6, 8, 10mm

output signal

25 bit SSI synchronous serial signal (Gray code, binary code optional)

power supply voltage

5....30VDC （Reverse polarity protection, overvoltage protection）

Single cycle resolution

Standard 12 bit 4096 and 13 bit 8192 (maximum optional 16 bit 65536 line)

Number of rotations

Standard 12 bit 4096 turns, maximum 14 bit 16384 turns (256 turns/64 turns optional)

repeatability accuracy

±2BIT

current consumption

<40mA (24V power supply)no-load

Signal adjustment

Direction adjustable, external zero position adjustable

encoding

Gray code or binary

maximum speed

6000r/min

Spindle load

Radial 200N, axial 80N

Protection level

IP65 or IP68

Starting torque

≤3Ncm

Operating Temperature

-35°C....85°C(Customizable working temperature)-45°C....85°C）

Storage temperature

-40°C. ...100°C

impact-resistant

1000m/s² , 6ms（100g）

Anti vibration

20g

connection method

8-core shielded cable or aviation plug

qualification method

Radial side out, axial rear out

Color Pin

Brown 2

White 1

Green 3

Yellow 4

Grey 5

Pink 6

Black 9

Blue 8

signal

Vcc

0V

CLOCK+

Time Clock

CLOCK-

Clock negative

DATA+

Data is positive

DATA-

Negative data

Reset or midpoint positioning

DIR rotation direction

Note: Our company will provide you with a more suitable product model and specifications according to your requirements (or customize according to your requirements)

SSI Protocol Description：

SSI is a synchronous serial signal, consisting of two pairs of RS422, one pair triggered by clock and one pair for data transmission.

As shown in the figure on the right, the absolute position value of the encoder is triggered by the clock signal of the receiving device, starting from the high bit (MSB) of the Gray code, and outputting a serial signal synchronized with the clock signal. The clock signal is sent from the receiving device and outputs N interrupt pulses based on the total number of bits of the encoder. When the signal is not transmitted, both the clock and data bits are high bits. At the first falling edge of the clock signal, the current value begins to be stored. From the rising edge of the clock signal, the data signal begins to be transmitted, and one clock pulse synchronizes one bit of data.

Among them, t3 is the recovery signal, waiting for the next transmission; N=13； 16；25； 28. According to the total number of bits in the encoder. T=4—11us； t1=1—5.5us； t2≤1us； T3=11-15.5 us (Clock - and Date - not shown).

In practical use, to ensure signal stability and a longer transmission distance, the recommended parameters are as follows:

T=8us（125KHz）； t1=4us； T2 '(actual reading delay time)=3_~4us； t3=15us

data processing：

The encoder outputs a Gray cycle code, which is first decoded into binary code starting from the high-order bits using XOR after reception. Due to the fact that Gray code is a cyclic code, it cycles through the maximum value code to 0, which means there is a sudden change between the maximum value and 0. Therefore, to avoid sudden data changes in the working process, it is recommended to use the middle position of the encoder data value as the starting position of the work. After the encoder is installed, rotate it to the actual starting point, and make the MIDP line of the encoder cable core positively short circuited with the power supply. The current signal output is the median of the encoder's total bit output value, and the MIDP line returns to power supply 0. After converting the current measurement value received into binary code in the future, the following steps should be taken:

Actual position value=(C-MidP) × Dir+starting point value

In the above equation, C is the current measurement value output by the encoder; MidP is the middle position value, which is 2^n-14096 for 13 bits and 32768 for 16 bits; 25 bits are 2048x8192, and 28 bits are 2048x65536. Dir is the rotation direction coefficient of the encoder, which is 1 when it is the same as the calculation direction and -1 when it is opposite to the calculation direction. It can also be changed by connecting the high and low levels through the DIR line on the encoder.

The starting point is not zero, and the calibration position can be determined by the user. Since the multi turn encoder can have 4096 consecutive measurements, starting from the starting point, both forward and reverse can have 2048 consecutive working strokes.