The PM Series from UIROBOT is a range of closed-loop integrated stepper motors that combine a stepper motor, incremental encoder, driver, and closed-loop controller into a single compact unit. Unlike CAN bus models, the PM Series interfaces with user controllers, PLCs, or computers through a simple 3-wire pulse-direction interface — making it ideal for applications where traditional pulse control is preferred. Built on the trusted UIM344 platform, these motors deliver closed-loop positioning with automatic missing step compensation, high-speed operation up to 3000 RPM, and configurations from NEMA 8 to NEMA 34. --- ## Key Features :::grid{cols=2 style=card} **Pulse-Direction Interface** Simple 3-wire control (PULSE, DIRECTION, ENABLE) compatible with most PLCs and motion controllers. No CAN bus configuration required — just connect and go. **Closed-Loop Control** Real-time position feedback with automatic missing step compensation. Eliminates lost steps common in open-loop stepper systems, ensuring reliable positioning even under overload conditions. **Microstepping Resolution** Full step to 1/128 microstep, configurable via UART. Default is 1/32 microstep. Ensures smooth, vibration-free motion at low speeds. **Wide Supply Voltage** 12–24 VDC for NEMA 8 and NEMA 11 models; 24–48 VDC for NEMA 17 and larger. Flexible integration into various power architectures. ::: :::grid{cols=2 style=card} **Optically Isolated Inputs** All logic inputs are optically isolated for noise immunity in industrial environments. Compatible with 3.3V, 5V, and up to 24V signals (with series resistor). **Adjustable Parameters** Working current, idle current rate, microstepping, and maximum missing steps configurable via UART interface using the free CFG344 configuration tool. **Integrated Design** Motor, encoder, driver, and controller in one unit — no external controller required. Aluminum alloy casing for durability and heat dissipation. **Protection Built-In** Overcurrent, overvoltage, and overtemperature protection standard across all models. ::: --- ## Product Lineup The PM Series covers five motor frame sizes from NEMA 8 to NEMA 34, with optional brake variants for NEMA 17 and above. ### Motor Specifications | Model | Frame Size | Holding Torque | Rotor Inertia | Rated Current | Supply Voltage | Brake | Encoder | Weight | |-------|-----------|---------------|--------------|--------------|---------------|-------|---------|--------| | UIM2040PM | NEMA 8 (20 mm) | 0.038 N·m | 2.9 g/cm² | 0.6 A | 12–24 VDC | — | Incremental | 95 g | | UIM2852PM | NEMA 11 (28 mm) | 0.16 N·m | 18 g/cm² | 0.8 A | 12–24 VDC | — | Incremental | 232 g | | UIM4247PM | NEMA 17 (42 mm) | 0.43 N·m | 75 g/cm² | 1.68 A | 24–48 VDC | — | Incremental | 441 g | | UIM4247PMB | NEMA 17 (42 mm) | 0.43 N·m | 75 g/cm² | 1.68 A | 24–48 VDC | Embedded | Incremental | 533 g | | UIM5756PM | NEMA 23 (57 mm) | 1.26 N·m | 300 g/cm² | 2.8 A | 24–48 VDC | — | Incremental | 830 g | | UIM5756PMB | NEMA 23 (57 mm) | 1.26 N·m | 300 g/cm² | 2.8 A | 24–48 VDC | Embedded | Incremental | 1010 g | | UIM8696PM | NEMA 34 (86 mm) | 6.5 N·m | 1900 g/cm² | 6 A | 24–48 VDC | — | Incremental | 3200 g | | UIM8696PMB | NEMA 34 (86 mm) | 6.5 N·m | 1900 g/cm² | 6 A | 24–48 VDC | Embedded | Incremental | 3800 g | ### Step Angle | Parameter | Value | |-----------|-------| | Intrinsic step angle | 1.8° | | After microstepping (1/128) | 0.0140625° | ### Order Code Structure ``` UIM [Motor Frame] [Motor Length] P M B [User Code] Motor Frame: 20 = NEMA 8 28 = NEMA 11 42 = NEMA 17 57 = NEMA 23 86 = NEMA 34 P = Pulse/Dir M = Incremental Encoder B = Embedded Brake □ = No Brake ``` **Example**: UIM5756PMB = NEMA 23 frame, 56mm length, Pulse/Dir, incremental encoder, with brake --- ## Applications :::grid{cols=3 style=card} **CNC Machines** Precise positioning for milling, routing, and engraving. Closed-loop control ensures accurate part dimensions without lost steps. **3D Printers** Reliable layer-to-layer positioning. Missing step compensation prevents print failures and improves print quality. **Packaging Machinery** Consistent indexing and positioning for labeling, filling, and wrapping operations. High speed capability for production throughput. ::: --- ## Quick Start ### Step 1 — Connect Hardware 1. Connect power supply (12–24 VDC or 24–48 VDC depending on model) 2. Wire PULSE, DIRECTION, and ENABLE signals from your controller 3. **Double-check all wiring before powering on** ### Step 2 — Send Test Pulses ```cpp // Arduino example #define PULSE_PIN 3 #define DIR_PIN 4 void setup() { pinMode(PULSE_PIN, OUTPUT); pinMode(DIR_PIN, OUTPUT); digitalWrite(DIR_PIN, HIGH); // Forward } void loop() { for (int i = 0; i < 1600; i++) { digitalWrite(PULSE_PIN, HIGH); delayMicroseconds(500); digitalWrite(PULSE_PIN, LOW); delayMicroseconds(500); } delay(1000); } ``` > **Tip**: For detailed wiring diagrams, signal specifications, and parameter configuration, see the [UIM344 technical reference](/docs/uim344). --- ## Safety Precautions ### Electrical Safety | Hazard | Precaution | |--------|------------| | High Voltage | Disconnect power before wiring. Use within specified voltage range only. | | Short Circuit | Ensure proper wire gauge and insulation. Install a fuse on the power input line. | | Grounding | Properly ground the controller to prevent electrical shock and noise interference. | ### Operational Safety | Hazard | Precaution | |--------|------------| | Overheating | Ensure adequate ventilation. Operating temperature: -20°C to +70°C. | | ESD | Use anti-static precautions when handling. Discharge static before touching terminals. | | Mounting | Secure the device firmly. Do not operate with loose mounting. | ### Mechanical Safety | Hazard | Precaution | |--------|------------| | Moving Parts | Keep clear of rotating shafts during operation. Wait for motor to stop before handling. | | Load Limits | Do not exceed rated torque and speed limits to prevent mechanical damage. | | Coupling | Ensure proper alignment between motor shaft and load to avoid vibration and wear. | --- ## Video Tutorial :::video[How to Control the UIM344 Series Closed-Loop Pulse-Direction Motor Using an Arduino](https://www.youtube.com/watch?v=iZMjSs_pVa0) ::: :::video[Missing Step Self-Compensation for UIM344 Closed-Loop Pulse-Direction Control Motor](https://www.youtube.com/watch?v=H2et6Vd74zg) ::: :::video[Nema 23 Closed Loop Stepper Motor with Pulse-Direction for CNC Router, Engraving Machine](https://www.youtube.com/watch?v=fjYjR656kKg) ::: > 📺 [More Video](https://www.youtube.com/@UIROBOT-ZJ) ## Related Products | Product | Description | |---------|-------------| | [UIM344](/docs/uim344) | Detailed technical reference, wiring, and configuration | | CM Series | CAN bus smart motors with incremental encoder | | CA Series | CAN bus smart motors with absolute encoder | | UIM342 | CAN bus motion controller | | UIC320A | USB to CAN 2.0B adapter | --- ## Resources :::tip For complete technical specifications, wiring diagrams, UART configuration, and sample code, see the **[UIM344 Pulse & Direction Closed-Loop Stepper Motor Controller](/docs/uim344)** page. ::: Download CFG344 configuration tool, user manuals, and sample code from the [UIROBOT Download Center](https://www.uirobot.com/serve/list-437.html). - **User Manual** — UIM344 V6.03 - **Configuration Tool** — CFG344 - **Sample Code** — Arduino, C#, Python - **2D / 3D Drawings** — STEP and DXF formats --- *Last Updated: 2026-06-25 | Based on UIM344 User Manual V6.03* > 💡 This page is a product family overview. For detailed technical specifications, wiring diagrams, pin assignments, and driver parameter configuration, refer to the **[UIM344 technical document](/docs/uim344)**.