The 3500/77-03-00 from Bently Nevada provides dedicated cylinder pressure monitoring for reciprocating compressors. This 4-channel device accepts signals from Bently Nevada approved pressure transducers. It conditions each input to derive critical pressure measurements. Furthermore, it continuously compares these values against user-programmable alarm setpoints. Therefore, operators receive reliable machinery protection and essential diagnostic information.
The 3500/77-03-00 accepts one to four channels of positive voltage pressure transducers. Scale factor ranges vary based on the pressure rating. For a 100 psia transducer, the scale factor is 95,000 mV/psi. For 250 psia, it becomes 38,000 mV/psi. Meanwhile, a 500 psia transducer uses 19,000 mV/psi. Higher pressure ratings include 9,500 mV/psi for 1000 psia, 3,800 mV/psi for 2500 psia, 1,900 mV/psi for 5000 psia, and 950 mV/psi for 10,000 psia.
Frequency response reaches 0 to 5.5 kHz on all configured pressure channels. Input impedance is 50 kΩ when using the Cylinder Pressure I/O module with internal terminations. Power consumption is 7.8 watts with transducer supplies at full load.
Pressure accuracy is within ±0.5% of the transducer's full range at +25°C (77°F). Over the full operating temperature range of -30°C to +65°C (-22°F to 150°F), accuracy remains within ±1.0%. These specifications apply to the 9.5 Volt range from +0.5 to +10.0 Volts.
The 3500/77-03-00 operates reliably in harsh industrial environments. Storage temperature ranges from -40°C to +85°C (-40°F to +185°F). Humidity tolerance is 95% non-condensing. Consequently, this monitor suits most reciprocating compressor installations.
Each channel of the Bently Nevada 3500/77-03-00 provides eight measured variables related to cylinder pressure operation. Five values relate to a single chamber. These include Discharge Pressure, Suction Pressure, Maximum Pressure, Minimum Pressure, and Compression Ratio. Additionally, the monitor calculates Peak Rod Compression, Peak Rod Tension, and Degree of Rod Reversal.
Users can configure Alert setpoints for each active measured variable. Danger setpoints are available for any two active measured variables. This flexible alarm structure allows precise protection based on specific compressor requirements.
The front panel includes three status LEDs for quick diagnostics. The OK LED indicates when the 3500/77-03-00 is operating properly. The TX/RX LED shows communication activity with other modules in the 3500 rack. The Bypass LED lights when the monitor is in Bypass Mode.
Buffered transducer outputs are available via coaxial connectors on the front panel. Each channel has its own connector. Output impedance is 550 Ω. Note that when using the Cylinder Pressure I/O module, these buffered outputs are inverted and offset by -2.265 Vdc. Each connector is short-circuit protected for added durability.
The 3500/77-03-00 provides a dedicated transducer power supply. Output is +23.0 ± 0.8 Vdc with 24.5 mA current limiting on each channel. This built-in power simplifies installation by eliminating external power supplies for compatible pressure transducers.
The monitor module measures 241.3 mm x 24.4 mm x 241.8 mm (9.50 in x 0.96 in x 9.52 in). It weighs 0.91 kg (2.0 lb). The I/O module dimensions are 241.3 mm x 24.4 mm x 99.1 mm (9.50 in x 0.96 in x 3.90 in), weighing 0.20 kg (0.44 lb).
For rack installation, the 3500/77-03-00 requires one full-height front slot. The corresponding I/O module occupies one full-height rear slot. Therefore, total rack space needed is two slots.
Installation requires careful handling to avoid electrostatic discharge damage. Always power down the 3500 rack before inserting or removing modules. The I/O module must match the monitor type exactly. Using the 3500/77-03-00 requires the Cylinder Pressure I/O module with internal terminations (I/O option 03).
Ensure proper grounding for all pressure transducer cables. Follow Bently Nevada's recommended wiring practices for optimal signal integrity. After installation, verify communication between the monitor and other rack modules using the TX/RX LED.
3500/77-03-00 Recip Cylinder Pressure Monitor Module (Main Board) – 1 unit
Cylinder Pressure I/O Module with Internal Terminations – 1 unit
Quick start installation guide
All orders are dispatched via FedEx, UPS, or DHL. Tracking numbers are provided within 24 hours after shipment. International delivery typically takes 3 to 7 business days depending on destination.
1. What type of pressure transducers work with the 3500/77-03-00?
The 3500/77-03-00 accepts Bently Nevada approved positive voltage pressure transducers. These must be 3rd-party units that meet Bently Nevada's approval criteria.
2. How many measured variables does each channel provide?
Each channel provides eight measured variables. These include Discharge Pressure, Suction Pressure, Maximum Pressure, Minimum Pressure, Compression Ratio, Peak Rod Compression, Peak Rod Tension, and Degree of Rod Reversal.
3. What is the frequency response of this pressure monitor?
The Bently Nevada 3500/77-03-00 delivers a frequency response of 0 to 5.5 kHz on all configured pressure channels. This range covers typical reciprocating compressor pressure pulsations.
4. Does the monitor include built-in transducer power?
Yes, the 3500/77-03-00 supplies +23.0 ± 0.8 Vdc to each channel. Current limiting is set at 24.5 mA per channel. This simplifies field wiring and reduces external hardware needs.
5. What do the front panel LEDs indicate?
The OK LED confirms normal monitor operation. The TX/RX LED shows data communication with other 3500 rack modules. The Bypass LED indicates when the monitor is in Bypass Mode, typically during maintenance or configuration changes.
| Brand Name | Bently Nevada |
| Model No. | 3500/77-03-00 |
| Product Type | Reciprocating Compressor Monitor |
| hasMerchantReturnPolicy | Adjust according to reality |
| Shippingdetails | Adjust according to reality |
