Orbit 60 Q4 Update: 80 Input Cards Cut to 10

The “Orbit 60 Q4 update” is real, but it is not new: Bently Nevada published “System Fundamentals – Output Cards” in December 2020, one quarter after the article that reduced its input module catalogue from more than 80 card types to ten. Read as a pair, those two posts are still the clearest public explanation of how an Orbit 60 system is specified — and why a retrofit from 3500 needs far fewer spare part numbers. What has changed since is the packaging: the 2026 catalogue adds compact chassis and a new recorder output card, while the two 2020 posts disagree with each other on one Keyphasor speed threshold. This guide separates what the updates actually said, what the current product page adds, and what to check before you quote a system.

By TenBN Editorial · Published 30 October 2026 · 11 min read

Fewer card types do not only shrink the spares shelf. They also shrink the number of rack drawings, wiring variants and configuration templates a plant has to keep alive for twenty years.

Quick answer: what the Orbit 60 Q4 update says

The input reduction happened one quarter earlier. The Q3 2020 article “Now – Less Spares!! How to Choose Input Modules” states that input card choices went from “over 80 different card types down to just 10”.
The Q4 2020 article covers the output side: the System Interface Module (SIM) protection-fault relay, electro-mechanical and solid-state relay modules, an eight-channel recorder output card, and buffered transducer outputs.
The stated benefit is spares, not just engineering. Bently Nevada claims the simplification can “reduce the required spares by half”.
Dedicated Keyphasor cards are no longer mandatory for most machines, and the old 3500 limit of four Keyphasor inputs per rack is gone.
One contradiction to know about: the Q4 2020 post recommends a dedicated High Speed Keyphasor above 12,000 rpm; the Q3 2020 post says 17,000 rpm.
What is current in 2026: 3U 10-slot and 19-slot racks, a 6U 28-slot rack, one SIM supporting up to 80 dynamic channels, plus 7-slot and 11-slot compact chassis listed for early 2027.

When was the Orbit 60 Q4 update published?

December 2020. The update belongs to a sequence of Orbit 60 publications that ran from the platform’s first public disclosure in late 2019 through 2021, and searching for “Orbit 60 Q4 update” in 2026 still returns that 2020 page. The sequence matters because the input-card story and the output-card story are one quarter apart — and most summaries that circulate online merge them into a single undated “recent update”.

Period	Publication	What it established
Late 2019	Platform disclosure	Orbit 60 introduced as a replacement architecture for 3500-class protection and condition monitoring.
Q3 2020	Now – Less Spares!! How to Choose Input Modules	Input module families cut from more than 80 types to ten; positively biased sensor inputs added; dedicated Keyphasor input no longer required for every machine.
Q4 2020 (December)	System Fundamentals – Output Cards	SIM protection-fault relay, relay modules, eight-channel recorder output, buffered transducer outputs, and the comms modules behind them.
2021	API 670 and TSI releases	API 670 turbomachinery applications, then TSI and multi-chassis bridging; 3U and 6U chassis counts published.
2026 catalogue	Orbit 60 product page and datasheets	3U 10/19-slot and 6U 28-slot racks, SIL-certified API 670 protection, 80 dynamic channels per SIM, 7-slot and 11-slot compact chassis scheduled for early 2027.

Why the date matters commercially: if you are budgeting a 2026 retrofit, the 2020 dates tell you which parts of the design are settled and which are still moving. The card families have been stable for six years. The chassis line-up has not — two compact sizes are announced but not yet shipping.

Why cutting 80 input types to 10 is a bigger deal than it sounds

On a 3500 rack, the input card you order is tied to the transducer you install: a proximity probe card, an accelerometer card, a Velomitor card, a seismic card, a Keyphasor card, and separate temperature and process-variable cards. Each family carries its own part number, its own spare, its own wiring convention and often its own configuration template. A plant with mixed machine trains ends up stocking a small catalogue of cards it may never use again.

Orbit 60 collapsed that. The ten input families cover the same measurement universe, and the measurement processing moves to the Protection Processing Module (PPM) instead of living on each card. The practical consequences:

Fewer part numbers on the shelf. One negative dynamic card family can cover proximity probes, accelerometers and velocity sensors, depending on the variant.
Fewer wiring variants. The same field wiring lands on the same card family across machine trains, which shortens commissioning and reduces documentation drift.
No four-per-rack Keyphasor ceiling. On 3500, Keyphasor inputs were a limited resource. On Orbit 60, any proximity-capable input can serve as a Keyphasor, so the constraint moves from slot count to signal quality.
A positive-voltage path for IEPE sensors. The PVT card added positively biased inputs, which is what made conventional IEPE accelerometers practical without an external signal conditioner.

Bently Nevada’s own claim is that the change can cut required spares by half. Treat that as a design target rather than a guarantee: the real number depends on how many machine trains you run and how much of your existing stock is 3500-specific.

The ten input families, and what each one accepts

The current datasheet list is the safest reference. Names below follow the 2026 product page and the 2020 articles; channel counts vary by variant, so confirm them on the datasheet before ordering.

Input family	Designed for	What it replaces on a 3500 rack
PAV — negative dynamic	Proximity probes, accelerometers, Velomitor velocity sensors	Separate prox, accel and Velomitor cards
PAS — negative dynamic	Proximity probes, accelerometers, seismic (velocity) sensors	Prox plus seismic cards
PAA — negative dynamic	Proximity probes, accelerometers, aero-derived inputs	Prox plus aero cards
PVT — positive dynamic	Positively biased transducers, including conventional IEPE accelerometers	External signal conditioners or dedicated IEPE hardware
High Speed Keyphasor	Phase reference on high-speed rotors	Dedicated Keyphasor card, four per rack
AC LVDT	AC linear variable differential transformers, four channels per card	Valve-position and stroke measurement hardware
RTD/TC temperature	Resistance temperature detectors and thermocouples	3500 temperature monitor
Isolated TC temperature	Thermocouples requiring channel-to-channel isolation	Isolated temperature cards
Isolated discrete input	Contact and discrete status signals	Discrete input cards
Isolated process variable	4–20 mA and other process signals	Process variable cards

Two design details are easy to miss. First, the card family does not decide what the measurement means: gain, filtering and alarm logic are configured in software against the PPM, which is why the same PAV card can feed a radial vibration channel and a shaft-absolute channel. Second, the simplification does not change the sensor side at all. A 3300 XL 8 mm proximity probe behaves exactly as it did on a 3500 rack; what changed is the electronics behind it.

What the Q4 update actually added: the output side

The Q4 2020 article answers a different question from the input article. Input cards decide what the system can measure; output cards decide what the protection system can do with the answer — trip a machine, energise an annunciator, hand a trend to the DCS, or export a buffered signal to a portable analyser. Five output paths were described, and a sixth is visible in today’s catalogue.

1. SIM protection-fault relay: one contact for the whole system

The System Interface Module carries a digital protection-fault relay rated 100 mA at 125 Vdc. It reports four states: OK, Protection Compromised, Protection Fault and Attention. The last two are the useful ones for maintenance: Protection Compromised and Attention are visible inside System 1 and can be exported over Modbus, so a plant can alarm on a degraded protection system without wiring another relay pair.

This is the single most under-reported part of the update. It gives operations one trustworthy answer to the question “is protection healthy right now?” instead of a per-module lamp count.

2. Relay modules: electro-mechanical or solid-state, voted in software

Relay modules actuate on alarm conditions defined in other modules and can combine alarms and statuses with standard logic elements. The Q4 article gives a clear split between the two hardware options.

Property	Electro-mechanical relay	Solid-state relay
Contact form	Double-throw	Solid-state output
Switching range	5 Vdc to 240 Vac, 0.1 to 4.5 A	Up to 125 Vdc
Load drive	Direct, or through an interposing relay	Direct, DC loads
Slot cost	Two slots	One slot
Voting logic	TRUE AND, NORMAL AND, NOT, OR	TRUE AND, NORMAL AND, NOT, OR

The slot cost is the decision that matters in a compact chassis. A solid-state relay buys back a slot and suits DC tripping circuits; an electro-mechanical relay handles AC circuits and higher current but consumes two slots. On a 3U 19-slot rack that difference compounds quickly if you are driving a wall of annunciators.

Voting is configured graphically in Orbit Studio, one channel per page, with drag-and-drop elements and connectors. The four blocks named in the article — TRUE AND, NORMAL AND, NOT and OR — are enough to build two-out-of-three trip logic, bypass handling and first-out indication without writing a separate PLC routine.

3. Recorder output: eight channels on one card

The recorder output module is a standalone eight-channel card that takes processed values from the input modules over the communication bus and converts them to analogue outputs for a DCS, PLC, historian or chart recorder. Three details make it more flexible than a conventional recorder card:

Mixed signal types on one card. Each channel can be set independently to 4–20 mA, 1–5 Vdc or 0–10 Vdc.
Multiple measurement types from one transducer. A single proximity probe input can drive different output channels as displacement, velocity and acceleration, so the DCS sees the units its loops expect without three field devices.
SIL available. The recorder path can be part of a safety-related architecture where the application requires it.

The current product page still marks the recorder output module as new, which is a reminder that the 2020 article described an architecture that took years to fill out across the catalogue.

4. Buffered transducer outputs: check the signal without touching the measurement

A BNC dongle on the front or back of an input card exposes an unconditioned, buffered copy of the transducer signal. The important word is buffered: tapping the signal cannot affect the values the module is monitoring. This is the port you use for a portable analyser, an oscilloscope during commissioning, or a fault investigation that needs raw waveform data rather than processed trends.

5. The output path behind the outputs: CGW, CMM and Bridge

Three modules decide where the output data actually goes, and the Q4 article treats them as part of the same story.

Communication Gateway (CGW) — two-way Modbus over serial or Ethernet, or EGD over Ethernet. It pulls process data from control systems, historians and human interfaces, and pushes Orbit 60 data out using standard industrial protocols. It is SIL-certified and designed to sit inside a protection loop. Orbit conneX uses the same path for state-based alarm levels.
Condition Monitoring Module (CMM) — the data acquisition and storage module. It talks to System 1 through Orbit aXess, a read-only data-diode path, so the business network cannot write back into protection. On-board solid-state memory holds days of data, and the spectra can be switched between 3,200-line and 800-line resolution from a desk.
Bridge — the base-to-base link that turns several chassis into one system, in linear or star topology, marketed as Orbit Xtend. Every chassis sees every channel, which is what makes a distributed installation behave like a single rack.

Displays complete the picture: the SIM drives external touchscreen displays showing the event list, module and channel data, alarm and OK status, and up to nine custom pages. Some 10-inch units are certified for hazardous areas, and each display needs its own power supply. A 3500 system guide is still worth reading alongside this, because many plants will run both generations side by side for years.

The one number you should not quote without checking

The two 2020 articles disagree on when a dedicated High Speed Keyphasor becomes necessary. The Q4 2020 output-card article states: “A dedicated High Speed Keyphasor is still recommended when rotor speeds exceed 12,000 rpm.” The Q3 2020 input-module article recommends the High Speed Keyphasor above 17,000 rpm.

Both sentences are Bently Nevada’s own. There is no public erratum that reconciles them, and the current product page simply lists the High Speed Keyphasor as one of the ten input families without a speed threshold. The defensible reading for a project specification is to treat 12,000 rpm as the conservative planning threshold — it is the later of the two statements and the safer of the two — and to confirm the number against the current datasheet and the application engineer before writing it into a scope of work. If you are replacing a 3500/25 Keyphasor module, the same conversation should settle whether the new system needs a dedicated card at all.

What this means for spares planning in 2026

The 2020 promise was “half the spares”. The practical version for a plant running mixed machine trains is three shelves instead of a dozen: one negative dynamic card family, one temperature family, and one set of relay and recorder outputs. Three rules follow from the documents.

Keep the sensor mix, not the card mix. Card simplification did not standardise transducers. If your trains run 3300 XL probes, Velomitor sensors and 3300 accelerometers, those part numbers stay on the shelf — for example the 330500 Velomitor and its 2 m variant, the 330400 accelerometer, or the 330450 high-temperature system for hot casings.
Keep a legacy 3500 lane open. Most sites will not migrate every rack at once. The current 3500 long-term support position and the 3500/25 Keyphasor system page matter as much as the Orbit 60 datasheet when you build the bridge year.
Do not design around the compact chassis yet. The 7-slot and 11-slot compact racks are listed for early 2027. A 2026 project should be drawn on 3U or 6U and treat the compact sizes as a future option.

Two edge cases deserve their own line in the budget. Wind turbines and other low-speed machines do not need a dedicated Keyphasor card at all — a 60M100 wind condition monitor is a different product line, but it illustrates the same principle: match the monitoring architecture to rotor speed rather than to a generic rack template. And two-wire seismic loops on older trains still need a 9200 Seismoprobe, which is a sensor decision the card count does not touch.

A 60-second selection table

Use this as a first pass, then confirm channel counts and certifications against the datasheet. The right-hand column is the output path, which is where the Q4 update earns its keep.

What you are monitoring	Input family	Typical sensor	Output path
Radial shaft vibration, high-speed rotor	PAV or PAS	3300 XL 8 mm proximity probe	Relay trip plus 4–20 mA to DCS
Casing vibration on a motor or fan	PAV	330500 Velomitor	Recorder output, velocity units
Gearbox or hot-section acceleration	PVT	IEPE accelerometer	Recorder output, acceleration units
Phase reference for balancing	Prox-capable input or High Speed Keyphasor	Keyphasor probe	System 1, no analogue output needed
Bearing metal temperature	RTD/TC	RTD or thermocouple	Relay alarm plus Modbus
Valve position or stroke	AC LVDT	LVDT	Recorder output to control system

Bottom line

The Orbit 60 “Q4 update” is a December 2020 document, and it is still the best short description of the platform’s output architecture: a single protection-fault relay on the SIM, relay modules with software voting, an eight-channel recorder card that mixes current and voltage outputs, buffered BNC taps that cannot disturb protection, and comms modules that make the data usable outside the rack.

The input reduction from 80-plus card types to ten is the headline most people remember, but it landed one quarter earlier and its real value is inventory and documentation, not measurement capability. If you are specifying a system in 2026, the things that changed since 2020 are the chassis options and the recorder card’s availability — not the ten input families.

For a plant that runs gas turbines, steam turbines, process compressors or petrochemical protection loops, the practical test is simple: count the transducer types you actually maintain, map each to one of the ten families, and count the output paths you need. If the output count is short, the recorder card is the cheapest fix in the architecture.

Frequently asked questions

When was the Orbit 60 Q4 update published?

It was published in December 2020 as “System Fundamentals – Output Cards”. The input-module reduction from more than 80 card types to ten appeared one quarter earlier, in the Q3 2020 article “Now – Less Spares!! How to Choose Input Modules”.

Did Orbit 60 really cut input card types from 80 to 10?

Yes. Bently Nevada’s Q3 2020 article states that input card choices went from over 80 different card types down to just 10, and that the change can reduce required spares by half. The ten families cover proximity, acceleration, velocity, Keyphasor, LVDT, temperature, discrete and process-variable inputs.

What did the Q4 2020 update add?

It described the output side: a SIM protection-fault relay with four states, electro-mechanical and solid-state relay modules with voting logic, a standalone eight-channel recorder output card with per-channel 4–20 mA, 1–5 Vdc or 0–10 Vdc, and buffered BNC transducer outputs on the input cards.

Do I still need a dedicated Keyphasor card?

For most machines, no: any proximity-capable input can serve as a Keyphasor, and the 3500 limit of four Keyphasor inputs per rack no longer applies. A dedicated High Speed Keyphasor is still recommended above a rotor speed threshold that the two 2020 articles state differently — 12,000 rpm in the Q4 article and 17,000 rpm in the Q3 article.

How many channels does the recorder output card have?

Eight channels on one standalone card. Each channel can be configured independently for 4–20 mA, 1–5 Vdc or 0–10 Vdc, and one transducer input can drive several output channels in different measurement units.

Which chassis sizes are available in 2026?

The product page lists a 3U 10-slot rack, a 3U 19-slot rack and a 6U 28-slot rack, with one System Interface Module supporting up to 80 dynamic channels. A 7-slot compact and an 11-slot compact chassis are listed for early 2027.

Sources and editorial note

Editorial note: this article is a reading of Bently Nevada’s public material, not a reproduction of its datasheets. Card channel counts, certifications and chassis availability should be confirmed with Bently Nevada or an authorised channel partner before they are written into a purchase order. The 12,000 rpm versus 17,000 rpm Keyphasor threshold is a discrepancy between two primary sources and is presented as such.