Description

The Allen-Bradley 845H-SJDZ24FWY2C/A is a high-performance optical incremental encoder from Rockwell Automation’s 845H series, designed to deliver precise speed and position feedback for demanding motion control applications. This encoder converts angular displacement into digital output signals, providing critical feedback to servo drives, variable frequency drives, and PLC-based motion controllers.

The 845H-SJDZ24FWY2C/A features a robust stainless steel shaft and heavy-duty bearings, making it ideal for direct shaft mounting on motors or machinery in harsh industrial environments. Its optical sensing technology provides 1000 pulses per revolution (PPR) with HTL (High-Threshold Logic) differential output, ensuring reliable signal transmission over long cable runs even in electrically noisy environments. With IP66-rated sealing, this encoder withstands dust, moisture, and temporary immersion, making it suitable for applications ranging from factory automation to heavy-duty material handling.

Application Scenarios

In a large automotive stamping press line, a PowerFlex 755 drive controls a servo feed mechanism delivering precise sheet metal positioning at speeds up to 1200 RPM. The existing encoder failed to provide reliable feedback due to the high vibration levels and electrical noise from nearby welding equipment, causing feed position errors and production scrap. The maintenance team replaced the failed encoder with the Allen-Bradley 845H-SJDZ24FWY2C/A. The 845H-SJDZ24FWY2C/A‘s HTL differential output (A, /A, B, /B, Z, /Z) delivered clean signals to the drive’s feedback card despite the 15-meter cable run and EMI-rich environment. The encoder’s 300 kHz output frequency and 1000 PPR resolution enabled the drive’s position loop to achieve ±0.1mm positioning accuracy at full speed. The plant’s controls engineer reported that the 845H-SJDZ24FWY2C/A‘s rugged construction and IP66 rating eliminated the encoder failure issues, reducing scrap by 35% and saving approximately $75,000 annually in material waste and downtime.

The Allen-Bradley 845H-SJDZ24FWY2C/A also excels in crane and hoist applications where motor-mounted encoders must survive shock loads, torque reversals, and outdoor weather exposure. In one installation, a bridge crane hoist motor was retrofitted with the 845H-SJDZ24FWY2C/A to provide speed feedback for variable-speed trolley positioning. The encoder’s stainless steel shaft and 40N axial load capacity withstood the hoisting motor’s thrust loads, while the -20°C to +85°C operating temperature range ensured reliable operation in unheated warehouse environments. The built-in Z-channel (zero pulse) provided absolute referencing during the crane’s homing sequence, simplifying commissioning and improving load positioning safety.

Parameters

Main Parameters	Value/Description
Product Model	845H-SJDZ24FWY2C/A
Manufacturer	Allen-Bradley / Rockwell Automation
Product Category	Optical Incremental Encoder
Resolution	1000 Pulses Per Revolution (PPR)
Output Signals	HTL Differential: A, /A, B, /B, Z, /Z (A/B quadrature + complementary + zero pulse)
Signal Frequency	Up to 300 kHz
Operating Voltage	10 – 30 V DC
Current Consumption	≤ 100 mA typical
Shaft Diameter	10 mm (stainless steel, with keyway)
Shaft Load Rating	Max radial: 80 N; Max axial: 40 N
Protection Rating	IP66 (seal); IP65 (housing)
Operating Temperature	-20°C to +85°C
Shock/Vibration	50g / 100g (11ms)
Electrical Connection	8-pin M12 circular connector, A-coded (male)
Cable Exit	Axial (from rear of encoder)
Mounting Style	Bolted flange mount
Material	Aluminum housing with stainless steel shaft
Weight	Approx. 200g / 0.45 lbs