Implementing 3-Switch XOR Ladder Logic with Internal Bit
Implement a 3-SPST switch XOR light circuit in LogixPro or RSLogix 500 using an internal relay bit. Includes truth tables, boolean equations, and verified.
The Bently Nevada 3500/25 125800-01 is a Keyphasor I/O Module with internal terminations for the 3500/25 Enhanced Keyphasor system. The module provides the rear I/O interface for Keyphasor transducer inputs and buffered Keyphasor signal outputs.
The 125800-01 is a non-isolated I/O configuration. It accepts signals from proximity probe transducers or magnetic pickups when used with the associated 3500/25 Keyphasor Module. Each Keyphasor channel supports transducer excitation of -24 Vdc at up to 40 mA.
The module provides internal termination for field connections. Buffered Keyphasor outputs are also available at the rear of the rack through Euro Style connections.
The PWA 184389-01 identification is associated with this 125800-01 assembly. For replacement procurement, 125800-01 should remain the primary Bently Nevada spare part number.
Keyphasor I/O Module for the Bently Nevada 3500/25 system
Internal termination configuration
Non-isolated Keyphasor I/O design
Supports up to two Keyphasor transducer input channels
Accepts proximity probe or magnetic pickup input signals
Input signal range of +0.8 V to -21.0 V
-24 Vdc transducer supply at 40 mA maximum per channel
Rear buffered Keyphasor signal outputs
Euro Style rear connections
Occupies one full-height rear rack slot
PWA identification 184389-01
Keyphasor transducer termination in 3500 machinery protection racks
Shaft rotational speed reference measurement
Phase reference signal acquisition
1X vibration amplitude and phase measurement support
Proximity probe Keyphasor applications
Magnetic pickup signal input
Replacement of existing 125800-01 internal-termination I/O modules
| Parameter | Specification |
|---|---|
| Manufacturer | Bently Nevada |
| System | 3500/25 Enhanced Keyphasor |
| Part Number | 125800-01 |
| PWA | 184389-01 |
| Product Type | Keyphasor I/O Module |
| Termination Type | Internal Terminations |
| Isolation | Non-isolated |
| Channel Capacity | Up to 2 transducer signals |
| Supported Transducers | Proximity probes or magnetic pickups |
| Rack Requirement | 1 full-height rear slot |
| Parameter | Specification |
|---|---|
| Input Signal Range | +0.8 V to -21.0 V |
| Input Impedance | 21.8 kohm minimum |
| Supported Input Frequency | 1 to 1,200,000 cpm (0.017 to 20 kHz) |
| Maximum Multi-event Input Frequency | 20 kHz |
| Passive Magnetic Pickup Requirement | Shaft speed greater than 200 rpm (3.3 Hz) |
| Parameter | Specification |
|---|---|
| Auto Threshold Minimum Signal | 2 V peak-to-peak |
| Auto Threshold Minimum Speed | 120 rpm (2 Hz) |
| Manual Threshold Range | 0 to -20 Vdc |
| Manual Threshold Minimum Signal | 500 mV peak-to-peak |
| Manual Threshold Minimum Frequency | Above 0.017 Hz |
| Hysteresis | User-selectable from 0.2 to 2.5 V |
| Parameter | Specification |
|---|---|
| Rear Buffered Outputs | 2 Keyphasor outputs |
| Rear Connection | Euro Style connectors |
| Buffered Output Impedance | 504 ohm maximum |
| Transducer Power Supply | -24 Vdc |
| Maximum Transducer Supply Current | 40 mA per channel |
| Parameter | Specification |
|---|---|
| Dimensions (H x W x D) | 241.3 x 24.4 x 103.1 mm |
| Dimensions (H x W x D) | 9.50 x 0.96 x 4.06 in |
| Weight | 0.46 kg (1.01 lb) |
| Rack Space | 1 full-height rear slot |
| Parameter | Specification |
|---|---|
| Operating Temperature | -30 to +65 degC |
| Storage Temperature | -40 to +85 degC |
| Relative Humidity | 95%, non-condensing |
| Interface | Function |
|---|---|
| CH 1 | Keyphasor transducer input channel |
| CH 2 | Keyphasor transducer input channel |
| Internal Terminations | Field connection for transducer signals and associated wiring |
| Buffered KPH Outputs | Rear buffered Keyphasor signal outputs |
| Rack Interface | Connection to the associated 3500/25 main module through the rack |
Verify the Bently Nevada spare part number 125800-01 before replacement.
Confirm that the existing system requires the internal-termination I/O configuration.
Verify that the installed I/O module is non-isolated before selecting the replacement.
Document existing CH 1 and CH 2 field wiring before module removal.
Isolate the applicable system circuits before disconnecting field wiring.
Inspect the module connector and rack mating interface before installation.
Reconnect transducer and buffered-output wiring according to the existing system documentation.
Confirm the corresponding 3500/25 Keyphasor Module configuration after installation.
Verify Keyphasor input and output signals before returning the monitoring system to service.
The 125800-01 should be configured through the associated 3500/25 Keyphasor system rather than treated as a standalone signal-processing device.
Confirm the selected transducer type and signal characteristics before commissioning. Proximity probes and magnetic pickups have different operating considerations.
Threshold and hysteresis settings should match the actual Keyphasor signal characteristics. Existing system configuration should be recorded before replacement.
Verify both Keyphasor input channels individually after installation.
Confirm that the transducer signal remains within the supported input range.
Check the buffered Keyphasor outputs where they are used by other monitoring or diagnostic equipment.
Compare shaft speed and phase-reference behavior with the machine's known operating condition before completing commissioning.
The 125800-01 is specifically the internal-termination, non-isolated Keyphasor I/O Module.
Do not substitute 126648-01 solely because both parts belong to the 3500/25 system. The 126648-01 uses external terminations.
Likewise, isolated I/O configurations are separate spare parts and should not be treated as equivalent without confirming the installed system architecture.
Use 125800-01 as the primary spare part number when sourcing a replacement. The PWA 184389-01 marking can be used as an additional identification reference.
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Returns & Warranty




The Bently Nevada 3500/25 125800-01 is a Keyphasor I/O Module with internal terminations for the 3500/25 Enhanced Keyphasor system. The module provides the rear I/O interface for Keyphasor transducer inputs and buffered Keyphasor signal outputs.
The 125800-01 is a non-isolated I/O configuration. It accepts signals from proximity probe transducers or magnetic pickups when used with the associated 3500/25 Keyphasor Module. Each Keyphasor channel supports transducer excitation of -24 Vdc at up to 40 mA.
The module provides internal termination for field connections. Buffered Keyphasor outputs are also available at the rear of the rack through Euro Style connections.
The PWA 184389-01 identification is associated with this 125800-01 assembly. For replacement procurement, 125800-01 should remain the primary Bently Nevada spare part number.
Keyphasor I/O Module for the Bently Nevada 3500/25 system
Internal termination configuration
Non-isolated Keyphasor I/O design
Supports up to two Keyphasor transducer input channels
Accepts proximity probe or magnetic pickup input signals
Input signal range of +0.8 V to -21.0 V
-24 Vdc transducer supply at 40 mA maximum per channel
Rear buffered Keyphasor signal outputs
Euro Style rear connections
Occupies one full-height rear rack slot
PWA identification 184389-01
Keyphasor transducer termination in 3500 machinery protection racks
Shaft rotational speed reference measurement
Phase reference signal acquisition
1X vibration amplitude and phase measurement support
Proximity probe Keyphasor applications
Magnetic pickup signal input
Replacement of existing 125800-01 internal-termination I/O modules
| Parameter | Specification |
|---|---|
| Manufacturer | Bently Nevada |
| System | 3500/25 Enhanced Keyphasor |
| Part Number | 125800-01 |
| PWA | 184389-01 |
| Product Type | Keyphasor I/O Module |
| Termination Type | Internal Terminations |
| Isolation | Non-isolated |
| Channel Capacity | Up to 2 transducer signals |
| Supported Transducers | Proximity probes or magnetic pickups |
| Rack Requirement | 1 full-height rear slot |
| Parameter | Specification |
|---|---|
| Input Signal Range | +0.8 V to -21.0 V |
| Input Impedance | 21.8 kohm minimum |
| Supported Input Frequency | 1 to 1,200,000 cpm (0.017 to 20 kHz) |
| Maximum Multi-event Input Frequency | 20 kHz |
| Passive Magnetic Pickup Requirement | Shaft speed greater than 200 rpm (3.3 Hz) |
| Parameter | Specification |
|---|---|
| Auto Threshold Minimum Signal | 2 V peak-to-peak |
| Auto Threshold Minimum Speed | 120 rpm (2 Hz) |
| Manual Threshold Range | 0 to -20 Vdc |
| Manual Threshold Minimum Signal | 500 mV peak-to-peak |
| Manual Threshold Minimum Frequency | Above 0.017 Hz |
| Hysteresis | User-selectable from 0.2 to 2.5 V |
| Parameter | Specification |
|---|---|
| Rear Buffered Outputs | 2 Keyphasor outputs |
| Rear Connection | Euro Style connectors |
| Buffered Output Impedance | 504 ohm maximum |
| Transducer Power Supply | -24 Vdc |
| Maximum Transducer Supply Current | 40 mA per channel |
| Parameter | Specification |
|---|---|
| Dimensions (H x W x D) | 241.3 x 24.4 x 103.1 mm |
| Dimensions (H x W x D) | 9.50 x 0.96 x 4.06 in |
| Weight | 0.46 kg (1.01 lb) |
| Rack Space | 1 full-height rear slot |
| Parameter | Specification |
|---|---|
| Operating Temperature | -30 to +65 degC |
| Storage Temperature | -40 to +85 degC |
| Relative Humidity | 95%, non-condensing |
| Interface | Function |
|---|---|
| CH 1 | Keyphasor transducer input channel |
| CH 2 | Keyphasor transducer input channel |
| Internal Terminations | Field connection for transducer signals and associated wiring |
| Buffered KPH Outputs | Rear buffered Keyphasor signal outputs |
| Rack Interface | Connection to the associated 3500/25 main module through the rack |
Verify the Bently Nevada spare part number 125800-01 before replacement.
Confirm that the existing system requires the internal-termination I/O configuration.
Verify that the installed I/O module is non-isolated before selecting the replacement.
Document existing CH 1 and CH 2 field wiring before module removal.
Isolate the applicable system circuits before disconnecting field wiring.
Inspect the module connector and rack mating interface before installation.
Reconnect transducer and buffered-output wiring according to the existing system documentation.
Confirm the corresponding 3500/25 Keyphasor Module configuration after installation.
Verify Keyphasor input and output signals before returning the monitoring system to service.
The 125800-01 should be configured through the associated 3500/25 Keyphasor system rather than treated as a standalone signal-processing device.
Confirm the selected transducer type and signal characteristics before commissioning. Proximity probes and magnetic pickups have different operating considerations.
Threshold and hysteresis settings should match the actual Keyphasor signal characteristics. Existing system configuration should be recorded before replacement.
Verify both Keyphasor input channels individually after installation.
Confirm that the transducer signal remains within the supported input range.
Check the buffered Keyphasor outputs where they are used by other monitoring or diagnostic equipment.
Compare shaft speed and phase-reference behavior with the machine's known operating condition before completing commissioning.
The 125800-01 is specifically the internal-termination, non-isolated Keyphasor I/O Module.
Do not substitute 126648-01 solely because both parts belong to the 3500/25 system. The 126648-01 uses external terminations.
Likewise, isolated I/O configurations are separate spare parts and should not be treated as equivalent without confirming the installed system architecture.
Use 125800-01 as the primary spare part number when sourcing a replacement. The PWA 184389-01 marking can be used as an additional identification reference.
Global Express Shipping
Returns & Warranty
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| Country of origin |
United States
|