Bently Nevada 136711-02 3500/61 RTD/TC Barrier I/O Module

Bently Nevada 136711-02 3500/61 RTD/TC I/O module with internal barriers

The Bently Nevada 136711-02 is the 3500/61 RTD/thermocouple I/O module with internal barriers and internal terminations, not isolated. The manufacturer ordering table lists it as I/O type 05 for the 3500/61 temperature monitor. It carries six temperature channels, each configured for an RTD or a thermocouple, with barrier circuitry built in for sensors that sit in hazardous areas.

It is the version for the 3500/61 monitor, which adds recorder outputs. Seven Star LLC supplies it in Oman and the GCC as a spare for existing racks.

136711-02 technical specifications

Values are from the 3500/60 and 3500/61 datasheet (141540 Rev. L).

How the 3500/61 temperature monitor works

The monitor reads six temperature sensors, linearises them for the configured sensor type, and compares each reading with user-set Alert and Danger limits. Typical uses are bearing metal temperatures, motor winding RTDs, and lube oil or process thermocouples. Alarm logic is programmed with the 3500 Rack Configuration software, and each channel can be a different type, so RTDs and thermocouples can be mixed on the same module.

In Triple Modular Redundant systems temperature monitors are installed in adjacent groups of three and vote on each channel. The barrier I/O module is an option for sensors in classified areas; the datasheet gives a lower minimum temperature range for the sensors when external barriers are used.

What makes 136711-02 different

Compared with the plain internal-termination modules this module adds barriers, which require checking the installation drawing and the 0°C minimum rack temperature. It is non-isolated, unlike the TC isolated I/O modules that give 250 Vdc channel isolation for thermocouples. The 3500/61 adds +4 to +20 mA recorder outputs per channel (0 to +12 Vdc across a 0 to 600 ohm load), and the recorder outputs reach the plant through the recorder cable to an external block.

Selection and ordering checklist for 136711-02

• Count the sensors and decide RTD or thermocouple for each channel.
• Check which RTD type: 100 ohm platinum (alpha 0.00385 or 0.00392), 120 ohm nickel or 10 ohm copper.
• Confirm the hazardous-area drawing and agency option.
• Verify that the minimum 0°C operating temperature suits the rack location.
• Choose the 3500/61 when each temperature must also go to a recorder or DCS as a current signal.
• Decide on external termination blocks only for non-barrier modules; barrier I/O has internal terminations.

Installation and maintenance

Wire each channel with the correct lead count: 3-wire or 4-wire for RTDs, extension cable of the right thermocouple type for TCs. Use shielded cable and ground the shield at one end. After insertion, check live readings against a calibrated reference and confirm the Alert and Danger setpoints. Open-circuit and sensor-fault detection should be tested by lifting a lead during commissioning.

Use in Oman and the GCC

Temperature monitoring of bearings and windings is standard on large motors, generators, compressors and turbines in the region. High ambient temperatures make baseline logging important, because a bearing running warm at the start of summer may be normal for that site but still needs a trend to prove it.

Using recorder outputs with 136711-02

The 3500/61 sends each channel as +4 to +20 mA, proportional to monitor full-scale, with 0 to +12 Vdc compliance across a 0 to 600 ohm load. This signal lets a 136711-02 installation feed a chart recorder, a DCS analogue input or a local indicator, and the monitor keeps working even when a recorder output is short-circuited. The recorder cable (134543-AAAA-BB) and recorder output external termination block (133892-01 or 133900-01) are listed as separate items in the datasheet.

Check the scaling at both ends when the module is replaced: the 4 to 20 mA range follows the configured full-scale of each channel, so a new 136711-02 only reproduces the same recorder signal if the monitor configuration is unchanged.

Information to send with your RFQ

• Part number 136711-02 and quantity
• Monitor part number and number of channels used
• Sensor types and area classification
• Delivery location in Oman or the GCC

Related Bently Nevada products: Bently Nevada 125680-01 3500/40M Proximitor I/O Module, Bently Nevada 128240-01 3500/42M Prox/Seismic I/O Module, Bently Nevada 135489-04 3500/40M Proximitor Internal Barrier I/O, Bently Nevada 3500/50 Tachometer Module, Bently Nevada 3500/50M Tachometer Module and Bently Nevada 3500/60-01-00 Temperature Monitor Module.

Documents and quotation

The manufacturer datasheet for the 3500/60 and 3500/61 temperature modules is attached on this page; read it together with your rack configuration and the site specification before confirming an order.

Seven Star LLC is an independent supplier in Muscat serving Oman and the GCC. Stock position, lead time, condition and the certificates that travel with the shipment are confirmed in the written quotation.