Description
EMERSON MMS6220 Dual-Channel Shaft Eccentricity Monitor
The EMERSON MMS6220 is a specialized dual-channel monitor designed for the continuous measurement and oversight of shaft eccentricity in rotating machinery. Part of the EPRO MMS6000 series, it is a critical component for turbine protection systems, ensuring the mechanical integrity of large-scale industrial equipment.
Product Introduction
The EMERSON MMS6220 utilizes advanced eddy current sensor technology to detect “bent shaft” or bowing conditions in steam, gas, and hydro turbines. By processing high-resolution signals, the module provides early warnings for potential mechanical failures during machine startup, shutdown, or steady-state operation. The MMS6220 Eccentricity Monitor is designed for 19-inch rack mounting and features high galvanic isolation to prevent signal interference.
EMERSON EPRO MMS6220
Technical Specifications (Datasheet)
The following table summarizes the key electrical and operational parameters for the module:
| Parameter | Specification |
| Number of Channels | 2 Independent Channels |
| Input Type | Eddy Current Sensor Systems (PR 642X Series) |
| Measurement Range | 0 to 10 mm (Adjustable via software) |
| Input Frequency | 0.017 Hz to 70 Hz (1.02 to 4200 rpm) |
| Analog Outputs | 0/4 to 20 mA and 0 to 10 V DC |
| Digital Communication | RS-232 (Front), RS-485 (Rear/System Bus) |
| Supply Voltage | +24 V DC (18 to 31.2 V DC) |
| Resolution | 10-bit / 14-bit (Depending on configuration) |
| Power Dissipation | Approx. 6.0 W |
| Country of Origin | Germany (EPRO GmbH / Emerson) |
Key Features
- Peak-to-Peak Measurement: Accurately calculates the difference between the maximum and minimum shaft displacement.
- Self-Test Diagnostics: Includes internal monitoring of the sensor circuit, cable integrity, and module hardware.
- Configurability: Fully programmable via laptop using the RS-232 interface, allowing for custom alarm set-points and filter settings.
- Rugged Design: Built to meet API 670 standards, making it suitable for high-vibration and extreme temperature environments.
EMERSON EPRO MMS6220
Installation & Usage Guidelines
- Mounting: The module should be inserted into a standard MMS6000 system rack. Ensure the locking handles are engaged to secure the backplane connection.
- Wiring: Use shielded cables for all sensor inputs. The signal inputs are differential and galvanically isolated from the power supply to ensure high noise immunity.
- Calibration: Before commissioning, the sensor gap must be calibrated using the DC voltage output to ensure the transducer is within its linear range.
- Integration: The RS-485 interface allows the module to transmit data directly to a Distributed Control System (DCS) or condition monitoring host.
Recommended Similar Models
For comprehensive machine health monitoring, the following modules within the Emerson EPRO/MMS family are frequently used together:
- MMS6110: Dual-channel bearing vibration monitor.
- MMS6120: Dual-channel relative shaft vibration monitor.
- MMS6210: Dual-channel shaft displacement/position monitor.
- MMS6310: Dual-channel speed and zero-speed monitor.
- MMS6410: Dual-channel relative case expansion monitor.
