Description
- Model: 1900/27
- Brand: Bently Nevada (Baker Hughes)
- Series: 1900 Series Machinery Protection
- Core Function: Stand-alone machinery protection for smaller assets (pumps, fans, motors).
- Product Type: 4-Channel Vibration and Temperature Monitor
- Key Specs: 4 Dynamic Inputs | 2 Temperature Inputs | 8 Relays | 4–20 mA Outputs
Key Technical Specifications
- Inputs:
- 4 Dynamic Channels: Supports Proximitors, Accelerometers, and Velocity Transducers.
- 2 Dedicated Temperature Channels: Supports Type E, J, K, T Thermocouples or RTDs.
- Outputs:
- Relays: 8 Programmable Relays (6 Protection, 1 Fault, 1 Aux).
- Analog: 4 Configurable 4–20 mA outputs.
- Communication: Modbus RTU (RS485) and 10Base-T Ethernet.
- Display: Optional remote display or integrated LED status.
- Configuration: Via 1900 Configuration Software (USB/Ethernet).
- Power: 24V DC or 110/220V AC (depending on the installed power supply).
- Mounting: DIN Rail or Bulkhead.
BENTLY 1900/27
Application Scenarios & Pain Points
The 1900/27 is the “little brother” to the 3500 rack system. It is designed for assets that are critical enough to require continuous protection but don’t justify the high cost of a full 3500 rack. If the 1900/27 fails, you lose the safety interlock for your motor or pump. Without its active monitoring, a bearing failure could go from a minor vibration alarm to a catastrophic mechanical seizure in minutes.
Typical Application Scenarios:
- Balance of Plant (BoP) Equipment Monitoring cooling tower fans, air compressors, and small steam turbines where space in the control cabinet is limited.
- Hydraulic Power Units (HPUs) Tracking vibration on the pump skid and oil temperature to prevent cavitation and fire hazards.
- Remote Pumping Stations Operating as a stand-alone protector that can signal a central SCADA via Modbus while maintaining local relay control for emergency trips.
Engineering Case Study: The “Single-Point” Protector
Background: A regional utility used the 1900/27 to monitor a critical raw-water intake pump. The pump was located in a remote hut nearly a mile from the main plant.
The Problem: The 1900/27 unit took a direct lightning hit through the sensor cables, frying the input stage. The pump was still running, but the plant had no way to know if it was vibrating excessively, and the “Auto-Trip” safety was gone.
The Solution: We provided a replacement 1900/27 unit. Since the 1900 series uses a specific configuration file (.mfg), we helped the customer find their backup file to upload to the new unit.
Result: The customer installed the new unit on the DIN rail and downloaded the config via USB. The system was back online and protecting the $80,000 pump within 24 hours of the lightning strike.
BENTLY 1900/27
Compatible Replacement Models
| Original Model | Replacement Model | Compatibility | Key Differences | Change Impact |
|---|---|---|---|---|
| 1900/27 | 1900/65 | ⚠️ Functional | General Purpose Monitor | Different wiring and config software |
| 1900/27 | 3500 Series | ❌ Incompatible | Rack-based system | Major redesign required |
| 1900/27 | 1900/27 (Rev E/F) | ✅ Direct | Manufacturing Revision | Fully interchangeable |
BENTLY 1900/27
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relation to 1900/27 | Quick Check | Action |
|---|---|---|---|---|
| “OK” LED Off | Power or Self-Test Fail | ✅ High | Check 24V DC input voltage. | Replace unit if power is good. |
| “Bypass” LED On | Logic in Maintenance | ⚠️ Medium | Check software settings for “Inhibit.” | Disable Bypass in configuration. |
| ERR 1 or ERR 2 | Channel Configuration Fail | ✅ High | Check if sensor type matches config. | Match transducer type in software. |
| Modbus Comm Fail | RS485 Termination | ⚠️ Medium | Ensure 120Ω resistor at end of line. | Check Device ID and Baud rate. |
Engineer’s Pro-Tip: “The 1900/27 is a great module, but it’s very picky about Bias Voltage. If you’re using a 3rd party accelerometer instead of a Bently Nevada sensor, make sure you set the ‘Upper’ and ‘Lower’ OK limits in the software properly. If the Bias Voltage drifts outside that narrow window, the unit will throw an ‘OK Fault’ and trip your relay (if configured for Fail-Safe). Also, the 1900 series software is different from the 3500 Rack software—make sure you have the ‘1900 Configuration Software’ installed before you head to the site!”
I have the digital pinout for the 1900/27-01 (Standard) and -02 (Hazardous Area) variations—let me know if you need the terminal mapping for your sensor type.
