Bently Nevada 3500/61-02-01 Temperature Monitor

3500/61-02-01 Bently Nevada Temperature Monitor

Product Introduction

The Bently Nevada 3500/61-02-01 provides reliable temperature monitoring for your 3500 series machinery protection system. This monitor accepts up to six RTD or thermocouple inputs simultaneously. It then outputs +4 to +20 mA recorder signals proportional to each channel's measured value. The 3500/61-02-01 uses a non-isolated I/O module with external terminations. Furthermore, its approval for Class I, Division 2 areas makes it suitable for hazardous environments. You can configure each channel independently for different transducer types.

Power Consumption and Outputs

The 3500/61-02-01 consumes 9 watts nominally. This rating applies specifically to the 3500/61 version with recorder outputs. Front panel LEDs provide clear operational status. The OK LED indicates proper monitor operation. The TX/RX LED shows communication with other rack modules. The Bypass LED lights when the monitor enters Bypass Mode.

For outputs, each channel provides a +4 to +20 mA recorder signal. These values remain proportional to the monitor's full-scale range. Short circuits on recorder outputs will not affect monitor operation. The voltage compliance ranges from 0 to +12 Vdc across the load. Load resistance should stay between 0 and 600 Ω. Resolution reaches 0.3662 µA per bit with ±0.15% error at room temperature. Over the full temperature range, error stays within ±0.4%.

Important Note on Type E Thermocouples

When using isolated I/O modules (-03 or -04 options) with Type E thermocouples, a temperature restriction applies. If your 3500 system operates in an ambient temperature above +35°C, the available full-scale range reduces. The reduced range becomes -60°C to +1000°C (-76°F to +1832°F). The rack configuration software may allow configuration down to -100°C. However, the system will not function properly with these settings. Therefore, you should never configure the 3500/61-02-01 to operate at -100°C with Type E thermocouples in high ambient temperatures.

I/O Module Isolation Details

The 3500/61-02-01 uses the -02 I/O ordering option (RTD/TC non-isolated I/O module). For reference, isolated versions provide system isolation of 500 Vdc and channel-to-channel isolation of 250 Vdc. Note that isolation is only required for fault scenarios. These voltages will not appear on I/O module inputs during normal wiring or field fault conditions.

RTD Excitation Current

The Bently Nevada 3500/61-02-01 supplies a precise RTD excitation current. The RTD current source value is 925 ±15 µA at 25°C per transducer. For 4-wire RTDs, a single supply handles excitation. For 3-wire RTDs, two supplies are used.

Environmental and Compliance

This monitor shares the same environmental limits as other 3500 series modules. Operating temperature ranges from -20°C to 65°C (-22°F to 149°F). Storage temperature spans -40°C to 85°C (-40°F to 185°F). Humidity tolerance reaches 95% non-condensing. The 3500/61-02-01 carries CSA/NRTL/C approval for Class I, Division 2 hazardous areas in North America.

System Requirements

Before installing the 3500/61-02-01, verify your rack configuration software version. Bently Nevada recommends using current versions for proper channel configuration. The monitor fits in any standard 3500 series rack slot. No special firmware requirements exist beyond the standard 3500 rack firmware.

Installation Guidelines

Install the 3500/61-02-01 by following these steps. First, power down the 3500 rack completely. Next, insert the monitor into any available slot. Push firmly until the backplane connectors engage. Then, tighten the retaining screws. Connect your RTD or thermocouple wires to the external termination block. For 3-wire RTDs, connect all three leads correctly. For 4-wire RTDs, follow the termination diagram. Finally, apply power and verify the OK LED illuminates.

Packaging List

• 3500/61 Temperature Monitor module – 1 unit

• 3500/61 I/O module (RTD/TC non-isolated, external terminations) – 1 unit

• Screw-type termination blocks – 1 set

• I/O module extension cable – 1 piece

• Installation instruction sheet – 1 copy

Note: External barriers for hazardous area wiring are sold separately.

Shipping Carrier: FedEx, UPS, DHL

Frequently Asked Questions (FAQ)

Q1: How many temperature inputs does the 3500/61-02-01 support?
The 3500/61-02-01 accepts from 1 to 6 RTD or thermocouple inputs. You can mix transducer types across different channels.

Q2: What is the difference between 3500/60 and 3500/61?
The 3500/61 includes recorder outputs (+4 to +20 mA per channel). The 3500/60 does not have recorder outputs. Power consumption also differs: 3500/61 consumes 9 watts while 3500/60 consumes 7 watts.

Q3: Can I use this monitor with isolated barriers in hazardous areas?
Yes, the 3500/61-02-01 works with external barriers. When barriers are installed, RTD ranges may be restricted. For example, platinum RTD (alpha 0.00385) with barriers covers -50°C to +850°C instead of -200°C to +850°C.

Q4: What happens if I short circuit a recorder output?
Short circuits on recorder outputs will not affect monitor operation. The 3500/61-02-01 continues normal function. This feature protects your monitoring system from field wiring faults.

Q5: Which RTD type does Bently Nevada recommend?
Bently Nevada recommends platinum RTDs with 0.00385 alpha. This type is the worldwide industrial standard. It also provides the widest temperature range from -200°C to +850°C.