Emerson AMS3120 A3120‑022‑000 Bearing Vibration Monitor
Product Description
AMS3120 is also commonly known in the market as CSI3120. A3120‑022‑000 is the complete order model. It belongs to the Emerson AMS series dual-channel bearing vibration monitoring unit. Developed for rotating machinery with a small number of channels, it measures absolute bearing vibration of equipment, suitable for online vibration monitoring and protection of small steam turbines, gas turbines, water turbines, compressors, pumps, fans and other equipment.
The whole unit is a wall-mounted field installation cabinet. All measurement parameters, alarm threshold output functions can be configured on site through configuration software without hardware DIP switch modification. It is suitable for renovation and new projects of medium and small units.
Core Features
- Dual-channel seismic sensor input, compatible with PR9268 series seismic velocity sensors, adopting Harting aviation plug interface for reliable and firm signal connection
- Full software configuration. Measurement range, high/low-pass filtering, alarm relay and analog output are all set by software. The measuring range can be flexibly selected according to the matched sensor
- Rich output interfaces
2 channels of buffered voltage output ±5VDC, cage terminal output with accuracy ±2.5%, used for vibration waveform acquisition
2 channels of isolated current output: 0 or 4 to 20mA, can also be set to reverse 20 to 4 or 0mA, electrically isolated, supporting open circuit and short circuit protection, maximum load 500 ohms, connected to DCS or PLC system
5 channels of relay dry contact output, maximum 48VDC 1A 50W, used for alarm and danger shutdown signal output - Industrial protective enclosure, cast aluminum anti-corrosion housing, IP65 protection grade. It can be directly installed on site without placing in control cabinet, reducing wiring cost
Key Technical Parameters
| Measurement Performance | |
| Sensor Type | PR9268 seismic velocity sensor |
| Measurement Range | Freely configured by software, matching sensor range |
| High-pass Filter | 5Hz,10Hz,15Hz optional |
| Low-pass Filter | Adjustable from 50Hz to 1500Hz |
| Environmental & Mechanical Parameters | |
| Shock Resistance | 20g peak |
| Operating Temperature | -20℃ ~ +65℃ |
| Protection Class | IP65 |
| Housing Material | Anti-corrosion aluminum alloy, weight approx.1300g |
| Mounting Type | Wall mounting |
| Certification | CE certification |
| Electrical Specifications | |
| Power Supply | 24VDC, allowable input 18VDC ~ 31.2VDC |
| Max Power Consumption | 6W |
| Current Output | Electrically isolated, open & short circuit protection, max load 500Ω |
| Relay Contact | 5 normally open contacts, max 48VDC, 1A, 50W |
Typical Application Scenarios
- Bearing vibration monitoring and protection for small steam turbine units, gas turbines and water turbines
- Rotating equipment of factory auxiliary machines such as compressors, centrifugal pumps and fans
- Renovation projects, upgrade of original vibration protection system, no additional cabinet required, direct wall mounting on site
- Application with small measuring points, only 1 to 2 channels of bearing vibration required, no need for large rack-mounted monitoring system
Model Information
Complete Order Model: A3120‑022‑000 AMS3120 Bearing Vibration Monitor
Working Logic
On-site PR9268 velocity sensor collects absolute vibration signal of bearing housing and sends it to AMS3120. The unit completes filtering and calculation internally. On one hand, it outputs 4-20mA analog quantity to DCS to display vibration value. On the other hand, when vibration exceeds alarm and danger threshold, it drives corresponding relay action to output switch quantity alarm or interlock shutdown. Meanwhile, buffered voltage output is provided to connect external acquisition equipment for vibration spectrum analysis, taking into account both equipment protection and simple diagnosis functions.
Document Source
Emerson AMS3120 Specification Sheet, Version Feb 2020
Matching Product Models
- Vibration sensor (mandatory): only compatible with PR9268 series seismic velocity sensors. AMS3120 hardware interface is specially adapted to PR9268 series electromagnetic velocity seismic sensors, directly connected by Harting aviation plug.
PR9268/201‑100: Vertical mounting, armored cable 5m with Harting connector, used for vertical measuring points of pump and fan bearing housing
PR9268/202‑100: Horizontal mounting, armored cable 5m with Harting connector, used for horizontal measuring points of turbine and compressor bearing housing
PR9268/301‑100: High temperature resistant version, vertical, 5m armored cable, used for high temperature fans and small steam turbines
PR9268/302‑100: High temperature resistant version, horizontal, 5m armored cable, used for steam auxiliary machine bearing vibration collection
Note: Cannot directly connect PR642x series eddy current displacement sensors. AMS3120 only measures absolute vibration velocity signal of bearing housing, not shaft relative displacement. - Connection Accessories
Harting Connector: The unit body is equipped with 2 Harting sockets for direct connection of PR9268 sensors. Self-made on-site cables adopt Han series heavy-duty connectors matching PR9268 plug definition.
M20 Cable Gland: The unit body has 2 M20 cable entries for power supply, 4-20mA and relay wiring cable inlet.
Power Module: 24VDC industrial power supply, output range 18~31.2VDC, max power consumption 6W. It is recommended to select 24V 1A industrial switching power supply. - Configuration Software & PC Tools
AMS3120 official PC configuration software: used to set range, high/low-pass filtering, alarm threshold, relay logic and 4-20mA mapping.
PC hardware requirement: computer with serial port or USB to RS232 converter. The device has no network port, only supports local serial port configuration, does not support remote network access. - Back-end Connected Equipment
DCS or PLC receives 2 channels of isolated 4-20mA output, max load resistance 500Ω
Vibration analyzer acquisition card uses 2 channels of ±5V buffered voltage output for waveform and spectrum analysis
Relay loop: 5 normally open relays 48VDC 1A 50W, connected to alarm lamp and shutdown interlock
FAQ
Q: Which sensors can AMS3120 A3120‑022‑000 connect to? Can it connect to eddy current probe?
A: Only PR9268 series seismic velocity sensors are supported. PR6423, PR6424 eddy current displacement probes are not supported. This product is positioned for bearing housing absolute vibration (housing vibration) measurement, not shaft relative vibration measurement. If shaft displacement monitoring is required, other modules such as AMS6500 and MMS6210 should be selected.
Q: What outputs does AMS3120 have? How to connect to DCS?
A: First, 2 channels of isolated 4-20mA current output, can be reversed to 20-4mA, max load 500Ω, connected to DCS AI card to output effective vibration value. Second, 2 channels of ±5V buffered voltage output, only used for vibration waveform collection, do not connect to DCS analog input. Third, 5 channels of relay dry contact output, configurable for alarm, danger and sensor fault, connected to DCS DI or interlock shutdown loop.
Q: Can the device be configured remotely via Ethernet web page?
A: Ethernet web remote configuration is not supported. Only local wiring configuration via PC serial port is available. All parameters are stored inside hardware and will not be lost after power failure.
Q: How to select filtering parameters? High-pass:5Hz,10Hz,15Hz; Low-pass:50Hz to 1500Hz.
A: Low-speed water turbine: high-pass select 5Hz. Pump, fan and small steam turbine: high-pass select 10Hz (most commonly used setting). High-speed small gas turbine: high-pass select 15Hz. Low-pass is generally set from 200Hz to 500Hz. It can be increased up to 1500Hz if high-frequency fault diagnosis is needed.
Q: Is AMS3120 intrinsically safe explosion-proof equipment?
A: The specification sheet only has CE certification. The main unit does not have Ex explosion-proof certification and shall be installed in safe area. If the sensor is installed in hazardous explosion area, explosion-proof version PR9268 sensor must be selected with isolation treatment. IP65 protection grade, suitable for on-site wall mounting, cannot be directly placed in hazardous explosion area.
Q: Inaccurate 4-20mA output with large reading deviation?
A: First check load resistance, cannot exceed 500Ω. Second confirm in software that range configuration matches PR9268 sensor sensitivity. Third confirm current output is electrically isolated, do not ground both ends on site to avoid ground loop interference. Fourth the device accuracy specification is ±2.5% full scale.
Q: What are relay contact parameters? Can it directly drive high-power trip coil?
A: Relay specification: max 48VDC, 1A, 50W. It cannot directly drive high-power trip coil. It is recommended to add small relay for isolation before driving field actuators.
Q: What is the difference between AMS3120 and AMS6500 MMS6312?
A: AMS3120 A3120‑022‑000: dual-channel on-site wall mounting, only supports PR9268 velocity sensor, IP65 protection, no cabinet required, suitable for small units, pumps and fans with few measuring points. AMS6500 MMS6312: multi-channel rack type cabinet mounting, supports eddy current, velocity and acceleration sensors, cabinet rack installation, suitable for large steam turbine units with multi-point system protection.
Q: Does AMS3120 come with local display screen?
A: No local display screen and no buttons. All parameter alarm readings can only be viewed through PC configuration software. On-site status can only be obtained via 4-20mA and relay output.
Q: What is power supply voltage range? Any requirements for power supply?
A: Rated 24VDC, allowable input 18VDC to 31.2VDC, max power consumption 6W. Isolated industrial power supply is recommended to avoid vibration measurement interference caused by power ripple.
Selection Tips
- Complete order model: A3120‑022‑000 AMS3120 Bearing Vibration Monitor. Do not write as MMS3120, MMS belongs to old rack series and easy to confuse.
- A complete bearing vibration monitoring system = A3120‑022‑000 main unit + 2 pcs PR9268 sensors + 24VDC power supply + PC configuration cable.
