Siemens S7-300 SM338 module with SSI encoder

Same function as imported SSI encoder, no need to change installation size, achieving height free replacement

SSI synchronous serial signal output multi turn 25 bit encoder with checksum value

Standard 25 bit SSI Gray code output, 12 bit 4096 line per cycle resolution, continuous 12 bit 4096 cycles, 1-bit checksum.

Under the 338 module, the 12 bit and 13 bit values automatically switch, with values ranging from 1.2.3 to 2.4.6 for 12 bit values and from 2.4.6 to 2.4.6 for 13 bit values.

*Value code wheel, high-precision and fully digitized, no need for external batteries, no signal interference or zero drift concerns.

*SSI digital output, fast and adjustable clock frequency of 500KHz, with high-speed and high-precision control.

*Standard 25 bit SSI Gray code output with 4096 resolution per cycle, continuous 4096 cycles, and 1 checksum.

*Wide operating voltage and extremely low current consumption.

*Interchangeable with various 24 and 25 bit SSI encoders from Germany

characteristic parameters

Working voltage: 10... 30Vdc polarity protection

Consumption current: ＜ 50mA (24Vdc) No load

Output signal: 24, 25 bit SSI synchronous serial signal, 24 bit, 25 bit clock signal automatic recognition compatible, Gray code

Linear resolution: 1/65536FS

Continuous turns: 1 to 4096 turns

Repetition accuracy: repeatability ± 2BIT (actual accuracy is related to installation accuracy and axis concentricity)

Clock rate: * Fast can set clock frequency to 500KHz, * using 125KHz

Working temperature: -25~80 ℃

Protection level: IP67 shell, IP65 shaft

Vibration impact: 20g, 10-2000Hz; 100g，6ms

Allowable speed: 2400 revolutions per minute

Connecting cable: 1-meter shielded cable radially out (other forms can be ordered)

Appearance features: Metal shell, sealed double bearing structure

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 position value of the encoder is triggered by the clock signal of the receiving device, starting from the high bit of the Gray code (MSB), 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 * falling edges 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 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, after passing through the * large value code value loop to 0, there is a sudden change between the * large 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 working start position. After the encoder is installed, rotate it to the actual working start 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 2n-1. It is 4096 at 13 bits and 32768 at 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.

*Value code wheel, high-precision and fully digitized, no need for external batteries, no signal interference or zero drift concerns.

*SSI digital output, fast and adjustable clock frequency of 500KHz, with high-speed and high-precision control.

*4096 resolution per cycle, continuous 4096 cycles, 1-bit checksum.

*Wide operating voltage and extremely low current consumption.

*Clamping flange, synchronous flange or blind hole shaft sleeve, standard external structure.

*Not OEM original *, no extension fee warranty within two years.

*Interchangeable with various 24 and 25 bit SSI encoders from Germany

The interchangeable models are as follows:

AVM58N-011K1RKGN-1212 AVM58N-011K1RKGN-1213

AVM58N-011K1AHGN-1212 AVM58N-011K1AHGN-1213

SAG-SLA0G-1213 SSI SAG-SLC0G-1213 SSI SAG-SLO0G-1213-C100-CRW

GM400.A102102 GM400.A101102 GM401.A102102 GM401.A101102

OCD-SX00X-1X1X-C10X-CRW OCD-PXA1X-0X0X-C10X-CRW

AC58/1213EC.42SGB AC58/1213EC.47SGB

ROQ425-512 SSI(631703-01) ROQ425 SSI(631703-29)

ROQ425 SSI(320200-07) ROQ425 SSI(320200-23)

ATM60-A4K12*12 EAMM58-B10-GS6PCA-4096/8192