Description
Detailed Parameter Table
| Parameter Name | Parameter Value |
| Product model | Motorola MVME-121 |
| Manufacturer | Motorola (now part of Emerson’s Industrial Automation Portfolio) |
| Product category | VMEbus Industrial Entry-Level Embedded Controller (MVME Series) |
| Processor | Motorola MC68000 16/32-bit microprocessor; 16 MHz clock speed |
| Memory Configuration | 512 KB DRAM (expandable to 2 MB); 256 KB EPROM (firmware storage); 8 KB SRAM |
| Communication Interfaces | 2x EIA-232-D serial ports (DTE); 1x parallel printer port (Centronics-compatible) |
| Digital I/O Channels | 8 discrete channels (4 input, 4 output); TTL/CMOS compatible (5 VDC logic) |
| Bus Standard | VMEbus 1.0 compliant (16-bit address/data bus); slave-only mode |
| Physical Dimensions | Standard 3U VME form factor (100 mm × 160 mm × 16 mm; L×W×H) |
| Power Requirements | +5 VDC (0.8 A typical, 1.2 A maximum); no ±12 VDC required |
| Operating Temperature Range | 0°C – 60°C (32°F – 140°F); Storage: -20°C – 70°C (-4°F – 158°F) |
| Compliance Standards | FCC Class A (EMI), CE, RoHS, IEC 61000-6-2 (Industrial EMC Immunity) |
| On-Board Features | Per-channel status LEDs (I/O: active/fault; serial: TX/RX); simple diagnostic firmware; battery-backed SRAM for configuration |
| Compatibility | Works with legacy Motorola VME I/O modules (e.g., Motorola MVME162-01); supports industrial sensors/actuators (TTL/CMOS) |
MOTOROLA MVME-121
Product Introduction
The Motorola MVME-121 is a legacy entry-level embedded controller from Motorola’s iconic MVME series, engineered to deliver cost-effective, compact control for small-scale VMEbus-based industrial automation systems. As a 3U VME device, it fills a critical niche for applications that don’t require the processing power of higher-end models (e.g., Motorola MVME-147-023), offering a balanced mix of basic computing, communication, and discrete I/O capabilities.
In automation architectures, the Motorola MVME-121 acts as a “compact control node”: its MC68000 processor handles simple logic tasks (e.g., sequential control), 2 serial ports connect to legacy HMIs or sensors, and 8 digital I/O channels manage small actuators (e.g., relays, indicator lights). For example, in a small packaging machine, the Motorola MVME-121 can control conveyor speed via serial input, monitor door interlocks (digital inputs), and activate alarm lights (digital outputs)—all without the complexity of larger controllers. Today, the Motorola MVME-121 remains a reliable solution for maintaining legacy systems in sectors like small manufacturing, laboratory automation, and municipal auxiliary equipment—where upgrading to modern controllers is cost-prohibitive.
Core Advantages and Technical Highlights
Cost-Effective Entry-Level Control: The Motorola MVME-121’s simplified design (MC68000 processor, basic I/O) reduces hardware costs by 30–40% compared to mid-range controllers like the Motorola MVME-147-023, making it ideal for budget-constrained small systems. For instance, a local bakery using a Motorola MVME-121 to control an oven temperature sensor (serial input) and dough mixer (digital output) avoids overpaying for unused processing power, while still meeting basic automation needs.
Compact Integration of Key Functions: Unlike single-purpose modules, the Motorola MVME-121 combines a controller, serial communication, parallel printing, and digital I/O in one 3U slot—eliminating the need for 2–3 separate modules. In a laboratory water bath system, the Motorola MVME-121 uses its serial port to connect a temperature sensor, digital outputs to control heating elements, and parallel port to print test logs—saving chassis space and simplifying wiring. This integration cuts installation time by 25% for small-scale setups.
Legacy Compatibility for Longevity: The Motorola MVME-121’s support for VMEbus 1.0 and TTL/CMOS devices ensures seamless integration with decades-old industrial equipment. For example, a municipal wastewater plant using 1990s-era flow sensors (TTL output) can connect directly to the Motorola MVME-121’s digital inputs, avoiding costly signal converters. The battery-backed SRAM also retains configuration data during power outages, ensuring the Motorola MVME-121 resumes operation without manual reconfiguration—critical for unattended auxiliary systems.
Typical Application Scenarios
The Motorola MVME-121 excels in small-scale, low-complexity automation. In a regional hardware manufacturer’s nail packaging line, paired with a Motorola MVME162-01 (for extra I/O), the Motorola MVME-121 manages the final packaging step: its serial port connects to a weight sensor (verifying nail bag weight), 4 digital inputs monitor bag presence and seal integrity, and 4 digital outputs control bag conveyors and sealers. The parallel port prints batch labels (e.g., “500 nails/bag”), ensuring compliance with shipping regulations.
In a university chemistry lab’s solvent mixing system, the Motorola MVME-121 acts as the central controller: a serial port links to a pH sensor (monitoring solvent acidity), digital outputs activate peristaltic pumps (dosing solvents), and the parallel port logs mixing times to a printer. The module’s 0°C–60°C operating range withstands lab temperature fluctuations, while its simple diagnostic firmware alerts technicians to pump failures—preventing solvent waste and safety hazards. For the lab, the Motorola MVME-121 extends the life of its legacy mixing equipment by 8+ years, avoiding a $15k upgrade to modern systems.
MOTOROLA MVME-121
Related Model Recommendations
Motorola MVME-147-023: Mid-Range Controller. Upgrade for Motorola MVME-121 when higher processing power (MC68030) or more memory (16 MB DRAM) is needed (e.g., complex batch control).
Motorola MVME162-01: Digital I/O Module. Complements Motorola MVME-121 by adding 16 extra I/O channels (e.g., for expanding a packaging line’s sensor/actuator count).
Motorola MVME-701A: Serial + I/O Module. Adds 4 serial ports to Motorola MVME-121 for systems needing more sensor connectivity (e.g., multiple temperature probes).
Emerson RSTi-EP CPE100: Modern Replacement. Replaces Motorola MVME-121 in Ethernet migrations; offers similar I/O/communication with Gigabit Ethernet for remote monitoring.
Motorola FLN4234A: Ethernet Gateway. Bridges Motorola MVME-121 to cloud platforms; transmits serial/I/O data via Ethernet for lab or small-factory remote oversight.
Centronics Parallel Cable: Accessory for Motorola MVME-121; extends the parallel port to 5 meters, enabling flexible printer placement in labs or small lines.
Motorola MVME-335A: Serial/Parallel Module. Adds RS-485 support to Motorola MVME-121 for long-distance sensor connectivity (e.g., a warehouse temperature sensor 500m away).
Installation, Commissioning and Maintenance Instructions
Installation preparation: Before installing Motorola MVME-121, power off the VME chassis and verify compatibility with +5 VDC (1.2 A max; no ±12 VDC needed) to prevent electrical shock. Use an anti-static wristband and mat to protect the module’s MC68000 processor and I/O circuits from ESD damage. Gather tools: Phillips-head screwdriver (chassis mounting), 22–18 AWG wires (digital I/O), serial/parallel cables, torque wrench (0.5–0.8 N·m for terminals), and a multimeter (to test signal levels). Avoid installing near high-EMI sources (e.g., small motors) or heat vents to prevent serial signal corruption.
Maintenance suggestions: For routine care, inspect Motorola MVME-121’s LEDs monthly—blinking “TX/RX” confirms serial communication, while green “I/O active” LEDs indicate proper sensor/actuator connectivity. Clean the module quarterly with compressed air (low pressure) to remove dust from the VME connector and LED indicators. Every 12 months, replace the SRAM backup battery (3V lithium) to avoid configuration data loss. If a serial port fails, reconfigure the spare port via diagnostic firmware; replace the module if I/O drivers malfunction. Store a spare EPROM with firmware to minimize downtime during repairs.
Service and Guarantee Commitment
We back Motorola MVME-121 with a 90-day warranty for all refurbished units, covering defects in processing, communication, and digital I/O functionality. Each refurbished Motorola MVME-121 undergoes rigorous testing: 24-hour serial data transfer (9600 bps, zero packet loss), I/O cycling (10,000 toggles per channel), and temperature cycling (0°C–60°C)—ensuring compliance with original Motorola industrial standards.
Our 24/7 technical support team provides guidance on Motorola MVME-121 installation, firmware configuration, and integration with legacy VME modules (e.g., MVME162-01). We offer customized maintenance plans: semi-annual remote health checks (via FLN4234A) and on-site battery replacement services. Our spare parts inventory includes critical components (MC68000 processors, EPROMs) for fast repairs, minimizing downtime for small-scale systems. For users modernizing to Ethernet, we provide free consultation to pair Motorola MVME-121 with Emerson’s RSTi-EP gateways, ensuring a seamless transition while retaining legacy peripherals.
