Industrial Automation Spare Parts List: What to Put on It Be

Industrial Automation Spare Parts List: What to Put on It Before the Machine Goes Down

An industrial automation spare parts list is a structured inventory of the components most likely to fail on a given machine — drives, PLCs, contactors, sensors, terminals, power supplies, breakers — priced per line with per-line MOQ and condition (new surplus, refurbished, or used). It exists so that when a line stops, the blocking part can be quoted and shipped within hours rather than identified from a photo two days later. A spare parts list is not the same as the machine's bill of materials: it omits what does not fail and adds consumables. An independent China-based industrial automation distributor like ours turns the list into a per-line quote, splits it across channels, and ships under one consignment.

Why the spare parts list is not a subset of the machine BOM

A typical panel builder's BOM is built for assembly: every line is the exact part the cabinet builder installed when the machine was new, with the right reference designators and the right order code. It is not built for failure. The PLC's processor, its digital input card, and its analog input card will all be listed — and they will be listed in the same way, even though only one of those three is likely to fail within the working life of the machine. The other two stay on the shelf for years, never replaced, and never ordered again.

A spare parts list inverts that priority. Instead of mirroring the BOM, it ranks lines by the rate at which they actually fail on a working machine, and by the cost of the failure when they do. A photoelectric sensor on a sorting conveyor fails more often than the PLC CPU; a 24 V power supply in a dusty cabinet fails more often than the PLC CPU; a basic microswitch on a guard door fails more often than the CPU. The spare parts list puts those items in tier one and demotes the rest to tier two or tier three, on a longer replenishment cycle.

This is the practical difference between a list that survives contact with a real maintenance budget and a list that gets ignored because it costs more than the downtime it would prevent. Buyers who treat the spare parts list as a procurement artefact rather than a copy of the machine BOM end up with something the maintenance team actually uses.

A related question is "Можно ли заказать неполный BOM и добрать позже?» — can I order a partial BOM and top it up later? The answer at the desk is yes, and that is exactly what a spare parts list is built for: the list exists so that a partial order today does not block the rest of the order tomorrow, and so that when the second wave of failures arrives, the desk already knows which lines you want and at what condition.

What the list usually misses

The most common error is putting the major modules first and leaving consumables off. A list that opens with the CPU, the drive, and the HMI panel looks thorough but is, in practice, a list of items that almost never fail on a working machine. What fails instead is the contact block on a pushbutton, the microswitch on a guard door, the spring terminal that loses tension after twenty insertions, the ferrite that overheats in a sealed enclosure, the encoder cable that frays at the strain relief, the overload relay that trips and is never reset.

Another common error is leaving firmware version and hardware revision off the line. A spare parts list that says only "Siemens S7-1200 PLC" is, from the desk's perspective, three different parts: the CPU 1212, the CPU 1214, and the CPU 1215 sit on different shelves and ship at different prices. Worse, a CPU 1212 with firmware V4.5 is not the same replacement as a CPU 1212 with firmware V3.0 — the program that runs on one will not necessarily run on the other without a firmware update step. A spare parts list that captures the firmware state of the installed hardware saves two days of work when the spare eventually ships.

A third error is mixing condition vocabulary. A spare parts list that says "contactors — 3 pieces" without naming whether the buyer will accept new surplus, refurbished, or used stock forces the desk to guess, and the guess is rarely aligned with the maintenance team's preference. The desk's job is to ask, line by line, what condition is acceptable, and to keep that answer on file for the next top-up. New surplus, refurbished, and used each have their place on a spare parts list; the buyer who names the preference up front gets a faster quote and a tighter fit.

A fourth error is ignoring the cabinet's environment. A sensor that is rated for indoor cabinet mounting is not the same product as a sensor rated for outdoor washdown, and a power supply that works at -10 °C is not the same product as one that works at +60 °C. A spare parts list that captures the ambient temperature, the IP rating, the pollution degree, and the supply voltage tolerance of the installed hardware lets the desk quote a directly compatible unit instead of an approximate replacement that turns into a redesign on the bench.

The seven categories a working spare parts list should cover

A practical spare parts list groups lines into seven categories, each with its own tier-one, tier-two, and tier-three sub-list. The categories below are derived from what actually fails on working machines in panel shops, packaging lines, bottling lines, water-treatment skids, and HVAC plant rooms — not from a textbook taxonomy.

Sensors and switches sit in tier one: inductive proximity sensors (such as the M12 inductive lines used on conveyor sortation), photoelectric through-beam and retro-reflective sensors, colour and contrast sensors, limit switches (including heavy-duty units such as the Honeywell 4TL1-3 and 2TL1-10 for outdoor and washdown locations), basic microswitches (such as the Honeywell BZ-2RQ and BZE6 series used on guard doors and access panels), and the connectors that go with them. The list should capture the switching function (NO/NC), the polarity (PNP/NPN), the cable length, and the connector type (M8/M12, 3-pin/4-pin). The list should also include a few spare lenses, reflectors, and mounting brackets — these are items that get lost on the floor and break during cleaning.

Contactors, motor starters, and overload relays sit in tier one or tier two, depending on the duty cycle. The list should capture coil voltage (24 VDC, 110 VAC, 230 VAC), contact arrangement (3P+1NO, 3P+1NC, 4P), current rating, and the matching overload relay range. A 9-amp AC-3 contactor that is rated for motor starting will not necessarily replace a 9-amp AC-1 contactor that is rated for resistive heating, and the spare parts list that captures the duty category saves a mis-specification.

Power supplies, breakers, and surge protection sit in tier one. The list should capture output voltage (24 VDC, 12 VDC), output current, redundancy topology (single, parallel, N+1), input voltage range, and the breaking capacity of the upstream breaker. A 24 VDC power supply that is rated for 10 A will not necessarily replace a 24 VDC power supply that is rated for 20 A — even if both physically fit the same DIN-rail footprint — because the inrush behaviour differs and the parallel-redundancy scheme may rely on a specific diode-or-mosfet-OR architecture.

Terminals, wiring, and cable accessories sit in tier one but are often forgotten because the maintenance team does not think of them as "spare parts". A working spare parts list includes spring terminals, screw terminals, push-in terminals, end brackets, end plates, jumpers, marking strips, ferrule crimps, and the ferrules themselves. A list that captures the terminal series (WAGO 2002, Phoenix Contact 850, Weidmüller A-series) and the wire range lets the desk quote a matching terminal block instead of a near-match that requires re-crimping the entire panel.

PLC and remote I/O modules sit in tier two or tier three. The list should capture the exact reference designator, the firmware version, the engineering-software compatibility (TIA Portal, STEP 7, GX Works, CX-Programmer), the program file path on the maintenance laptop, and the matching GSD/GSDML/EDS file version. A spare parts list that captures the firmware state of the installed module lets the desk quote a replacement at the correct firmware level, and lets the maintenance team plan a firmware-update step instead of discovering it on commissioning night.

Drives and servo modules sit in tier two. The list should capture the power rating (in kW), the input voltage, the overload rating (150 % for 60 s, 200 % for 3 s), the braking resistor, the encoder interface, the control terminals, and the matching motor part number. The spare parts list does not have to capture the parameter set — that lives in the project file — but it does have to capture enough mechanical and electrical detail that the desk can quote a current equivalent from the same manufacturer, and flag any firmware-version mismatch as a known unknown.

HMI panels and operator interfaces sit in tier three. The list should capture the screen size (4", 7", 10", 15"), the resolution, the touch technology (resistive, projected capacitive), the communication interface (PROFINET, EtherNet/IP, Modbus TCP), the project-engineering software (WinCC, ProTool, EasyBuilder), and the project file version. HMI panels are the items that are most often upgraded rather than replaced as spares, and a list that captures the project-file state lets the maintenance team decide whether a like-for-like spare or an upgrade is the right answer for the line.

How the line items should be priced and stocked

Once the seven categories are filled, the list turns into a quote artefact. Each line carries three numbers and a condition label: a per-piece price (indicative, confirmed per line on the quote), a per-line MOQ (because a one-piece order on a five-piece pack is a different transaction from a one-piece order on a one-piece pack), a per-line lead time (quoted per order, not held from the first quote), and a condition (new surplus, refurbished, or used). The list also carries a fourth item that the buyer often misses: a per-line substitute-not-required flag. A line that must not be silently swapped for a near-match — for example, a 24 V power supply whose output impedance interacts with the downstream sensor wiring — should be flagged on the list, and the desk will quote that line alone rather than offering a near-match. When the maintenance team needs a replacement for a flagged line, the desk's role is to quote the line at the documented condition and let the maintenance team verify against the original manufacturer datasheet and their own qualification process; we do not claim that any third-party alternative fits without that check.

Stocking at the desk is a separate question. The desk does not keep a fixed catalogue of spare parts the way an authorised distributor would; the model is closer to a search-and-quote desk than to a warehouse. What the desk does is hold the buyer's spare parts list on file, run it through the supplier network on each reorder cycle, and quote the lines that the buyer is ready to buy. That distinction matters because it explains why the desk does not publish a "stock list" of spares — there is no such list, and any dealer who publishes one is either lying about coverage or holding stock that the buyer will pay for indirectly.

The practical effect for the buyer is that a partial reorder is normal rather than exceptional. The buyer can take the spare parts list, mark the lines that have failed since the last order, send the marked subset, and the desk quotes just that subset. The remaining lines on the spare parts list stay on file for the next failure event, and the next quote reuses the same per-line MOQ and condition preferences rather than starting from scratch. This is the model that survives the maintenance budget, and it is the model the desk is set up to handle.

For buyers in Russia and the CIS, the same model works with the usual logistics overlay: the desk is an independent industrial automation distributor based in China; quotations are issued EXW, FCA, DAP, or DDP, with the term stated on the quotation; payment is by bank transfer against a proforma invoice or via Payoneer; and the shipment travels under one commercial invoice and one packing list. We screen end users and end uses, classify before quoting, and decline transactions that cannot be screened. The list itself is identical to the list a buyer in any other market would hold — what differs is the trade term, the settlement route, and the documentation path.

What the desk does with the list, and what it does not

The desk's role with a spare parts list is narrow and explicit. The desk accepts the list in any format — Excel, PDF, a photo of a handwritten sheet, an ERP export, or a CSV pulled from a maintenance log — and treats each line as a sourcing task rather than as a single procurement decision. The desk quotes each line on its own: price, MOQ, lead time, and condition. The desk does not merge lines into a blended figure, does not round up to a single-price headline, and does not swap an obsolete line for a "similar" one without saying so. The desk reports what it found, line by line, and the buyer decides which lines to confirm.

The desk also acts as a standing-request holder. A spare parts list that contains lines that cannot be sourced today is not discarded; it is held and re-checked on a cadence that the buyer sets. When the lines become available — because a decommissioned machine was parted out, because a franchised channel released a last-time-buy window, because a parallel inventory was found at a stocking distributor — the desk quotes them on the same per-line format and the buyer decides. This is the practical answer to «Где найти снятый с производства компонент?» — where to find a part that is no longer in production? The list, held on file, is the answer.

What the desk does not do is equally important. The desk does not own the machine, does not run maintenance on it, does not hold a fixed catalogue of spare parts, does not offer a repair service, does not hold EAC or TR CU certification, does not issue conformity declarations on the buyer's behalf, and does not act as a customs broker outside the scope of a DDP term. The desk does not claim that a given spare part satisfies a functional-safety requirement, does not advise on a safety-circuit substitution, and does not certify a component for a medical-device application. A spare parts list that covers a safety-rated loop (an e-stop chain, a guard-door interlock, a SIL-rated input) is not a substitute for the buyer's functional-safety process: any line that touches a certified protective circuit is better to keep on the original part than to swap for a near-match, and the desk will not recommend otherwise. Where the buyer's quality system requires any of those, the desk is not the right counterparty; the buyer's importer, conformity body, or functional-safety engineer is. The desk's role is to find the part and ship it; the rest stays on the buyer's side.

The desk also does not commit to a fixed transit time, a fixed MOQ across the whole order, or a fixed condition across the whole lot. Lead time is quoted per order, MOQ is quoted per line, and condition is stated per line. This per-line discipline is what lets a partial reorder work, and it is what stops a single expensive line from hiding inside a lump-sum quote.

When the list has to be revised, and when it has to be thrown away

A spare parts list is a living document. It gets revised when the machine is upgraded, when the maintenance team finds a new failure mode, when the manufacturer announces an end-of-life on a line, when a supplier stops carrying a sub-component, and when the regulatory environment of the destination market changes (for example, when a control panel needs to move to a higher pollution-degree rating because the cabinet is moved from a clean room to a washdown area). The list is thrown away when the machine is decommissioned, when the spare parts philosophy of the buyer changes (for example, when the maintenance team moves from preventive stocking to condition-monitoring), or when the spare parts list has drifted so far from the installed hardware that it can no longer be trusted.

The most common reason a spare parts list stops being useful is firmware drift. A CPU that was bought with firmware V3.0 in 2020 may now only be available on the secondary channel with firmware V4.5, and the maintenance team's program file may not be portable. The spare parts list that captured the firmware state of the installed hardware at procurement time is the document that tells the maintenance team when to plan a firmware update, and when to expect a half-day commissioning step instead of a one-hour swap.

The second most common reason is environmental drift. A sensor that was originally specified for indoor cabinet mounting at +5 °C to +40 °C may now be installed in a washdown area at -10 °C to +55 °C. The spare parts list that captured the original environmental class is the document that flags the drift, and the desk can then quote a sensor at the higher environmental rating — or, more honestly, flag the line as one that needs a redesign rather than a replacement.

The third most common reason is a manufacturer end-of-life announcement. When Siemens, Schneider, or Allen-Bradley announces the last-time-buy window for a platform, the spare parts list is the document that tells the buyer which lines are about to leave the market and which lines can still be sourced through the independent channel. The desk checks the list against the announcement, reports the affected lines, and the buyer decides whether to extend the list (last-time-buy), shorten the list (drop the line), or hold the list and re-check on the next cycle.

A practical next step

Send the spare parts list in any format you have. Excel is fastest, PDF works, and a photo of a handwritten sheet is acceptable if the line items are legible. For each line, name the part number or the marking text, the quantity per line, the acceptable condition (new surplus, refurbished, used, or any), and any line that must not be silently substituted for a near-match. The desk returns a per-line quote with price, MOQ, lead time, and condition on every row, and holds the list on file for the next top-up. For buyers in Moscow, the Russian regions, and the CIS, the quotation states the trade term (EXW, FCA, DAP, or DDP) and the settlement route (proforma invoice to a Russian entity, bank transfer, or Payoneer); the shipment travels under one commercial invoice and one packing list, and the desk screens the end use before quoting.

The list is the buyer's tool. The desk's role is to keep the lines on file, run them through the supplier network on each cycle, and ship the confirmed lines under one consignment. What the buyer gains is hours of sourcing work moved off the maintenance team's plate, and what the buyer keeps is the discipline of per-line condition, per-line MOQ, and per-line lead time. Send us your BOM via the inquiry form and we will respond line by line with per-line price, MOQ, lead time, and condition.

Data Notes

Independent distributor, not an authorized distributor. We are an independent China-based industrial automation distributor and sourcing desk. We do not represent Honeywell, Siemens, Schneider, or any other brand as an authorized distributor; we do not hold EAC or TR CU certification; we do not issue conformity declarations on the buyer's behalf. Confirm any certification requirement with your importer or conformity body.
Per-line condition discipline. Condition (new surplus / refurbished / used), MOQ, lead time, and price are stated per line before you commit. We do not blend lines into a single lump sum, and we do not describe an untested used unit as refurbished.
Catalog grounding. This article references Honeywell BZE6-2RQ8, BZ-2RQ784, BZ-2RW82255-A2-S, BZ-2RW826-A2, LSA3K, LSA1A, 4TL1-3, 2TL1-10, 2NT1-7, 2NT1-6, 1TL1-7 microswitch and limit-switch families, plus cross-brand anchors for Siemens S7-1200 (6ES7212-1AE40-0XB0), Phoenix Contact QUINT power supplies, WAGO 2002 terminals, and Weidmüller A-series terminals. The MPNs reflect parts available on the desk's supplier network at the time of writing; specific stock is what the supplier confirms on the day the quote is prepared.
No functional-safety or medical-conformity conclusion. Whether a given spare part satisfies a functional-safety requirement (SIL/PL) or is acceptable in a medical-device build is a determination that belongs to the buyer's engineering process and quality system, not to a sourcing desk.
DDP and screening. Where the quotation states DDP, the desk arranges import clearance as part of the delivery. The desk screens end users and end uses, classifies before quoting, and declines transactions that cannot be screened.

By the aoctrl sourcing desk. Last updated 2026-09-21. Data through September 2026.

FAQ

What should an industrial automation spare parts list actually include?

A working spare parts list includes sensors and switches, contactors and motor starters, power supplies and breakers, terminals and wiring accessories, PLC and remote I/O modules, drives and servo modules, and HMI panels — each ranked by failure rate and by the cost of the failure. The list omits items that almost never fail (the PLC CPU, the main contactor coil) and adds consumables and wear items that the maintenance team would otherwise have to reorder ad hoc.

How is a spare parts list different from a machine bill of materials?

A BOM is built for assembly: every line is the exact part the cabinet builder installed when the machine was new. A spare parts list is built for failure: every line is ranked by the rate at which it fails on a working machine and by the cost of the failure when it does. The two documents overlap on roughly 30 % of lines; the other 70 % belong to one list or the other.

Can the spare parts list be ordered in parts and topped up later?

Yes. The desk holds the full list on file, and each reorder cycle quotes only the lines the maintenance team marks. Prices, MOQ, and condition are re-checked at the time of each order rather than held from the first quote. This is the model that lets a maintenance budget survive a quarter of failures without the buyer having to redo the source-of-truth document on each event.

What condition should the spare parts be in — new, refurbished, or used?

It depends on the line. A microswitch on a guard door is a candidate for new surplus because the price difference is small and the failure consequence is operational. A PLC power supply in a tier-three subpanel is a candidate for refurbished because the price difference is large and the failure consequence is recoverable. The desk asks the buyer, line by line, what condition is acceptable, and the answer stays on file for the next reorder.

How long does it take to quote a spare parts list?

Single-line and short-list requests are usually answered the same working day; a long mixed-brand list takes longer because each line is sourced individually. The desk does not quote a fixed turnaround as a service guarantee — the response time depends on the list and on how quickly suppliers confirm. For urgent top-up requests (a single failed line, a machine-down event) the desk starts from the part number or the photo, not from a form.

Can the spare parts list include lines that are no longer in production?

Yes. Lines that are obsolete, discontinued, or allocation-constrained are exactly the lines that the desk is set up to hold and re-check. A standing request lets the desk revisit the line on a cadence the buyer sets — monthly, quarterly, or on-demand — and quote the line when stock becomes available. This is the practical answer to the question «Где найти снятую с производства деталь?» — and it does not require the buyer to keep asking.

What does the desk not do with a spare parts list?

The desk does not own the machine, does not run maintenance on it, does not hold a fixed catalogue of spare parts, does not offer a repair service, does not hold EAC or TR CU certification, does not issue conformity declarations, does not commit to a fixed transit time, and does not advise on a functional-safety or medical-device substitution. The desk's role is to find the part and ship it; the rest stays on the buyer's side.