Controls and Automation Scope for Estimators

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Controls and automation is one of the most consistently underscoped areas on a manufacturing plant estimate. If you come from commercial construction, you know how to read an electrical sub’s bid — wire sizes, panel schedules, conduit runs. What you are not trained to scope is what happens after the wire lands at the panel: the programmable logic controllers, the software, the network infrastructure, and the integration engineer who teaches the whole system to run a production line. That is the controls integrator’s world, and it is a distinct scope with distinct costs.

The core problem for estimators: The electrical sub installs the hardware. The controls integrator makes it work. These are different contractors with different scopes, and neither one automatically covers the other’s work. Missing the boundary between them is how a project ends up $150K–$400K short on controls.

Controls Integrator vs. Electrical Sub — The Scope Split

Understanding this distinction is the foundation of controls estimating.

What the Electrical Sub Does

The electrical sub’s scope stops at the terminal block. They:

Pull wire and conduit from the motor control center (MCC) to field devices
Set and wire MCC panels (starters, VFDs, breakers)
Mount and wire field instruments (transmitters, switches, sensors) per instrument loop drawings
Connect instrument wiring to PLC I/O cards per the wiring schedule
Terminate, label, and document all field wiring

The electrical sub does not write PLC code, configure SCADA, develop HMI screens, tune control loops, or commission the control system. If you ask an electrical sub for a controls integration price, they will hand you a price for wire and conduit — not for any of the above.

What the Controls Integrator Does

The controls integrator’s scope starts at the terminal block and goes up the software stack. They:

Write PLC programs — the logic that reads inputs (sensors, switches) and drives outputs (valves, motors, conveyors)
Develop HMI screens — the operator touchscreen interface for running, monitoring, and alarming the process
Configure SCADA systems — plant-wide supervisory visualization, trend logging, alarm management
Perform Factory Acceptance Testing (FAT) — tests the system at their facility before it ships to site
Perform Site Acceptance Testing (SAT) — tests the system integrated with actual equipment on site
Commission and tune control loops — PID tuning for temperature, flow, pressure, level loops
Document the system — functional design specifications, I/O lists, cause-and-effect matrices, O&M manuals

Estimator tip: The controls integrator scope almost never appears in the electrical sub’s bid unless it is explicitly included in the RFP. Always issue a separate RFP to the controls integrator. If you roll controls integration into the electrical scope without verification, you will have a scope gap.

The Controls Stack — Five Layers, Five Cost Centers

Think of the controls system as a stack of five layers. Each layer has a different cost structure and different parties who provide and own it.

Layer 5: MES / ERP Integration          ← Enterprise software; owner IT project
Layer 4: SCADA / Historian              ← Plant-wide supervisory; controls integrator
Layer 3: HMI                            ← Line/area operator interface; controls integrator
Layer 2: PLC / DCS Controller           ← Machine control logic; controls integrator
Layer 1: Field Instruments & Devices    ← Sensors, valves, motors; electrical sub + vendors

Layer 1 — Field Instruments and Devices

Everything in the field: flow transmitters, level sensors, temperature elements, pressure transmitters, control valves, motor starters, VFDs, limit switches, photoelectric sensors.

Who provides it: Split between the equipment vendor (instruments integrated into their skid or machine) and the electrical sub (field instruments for the GC’s process scope). Some instruments are Owner-Furnished, Contractor-Installed (OFCI).

Risk: The gap between machine vendor instrument scope and plant instrument scope is where devices fall through. Confirm the boundary at each equipment connection point.

Typical cost: $200–$2,000 per instrument point installed (wide range by type and installation complexity).

Layer 2 — PLC / DCS Controller

The programmable logic controller (PLC) is the industrial computer that executes control logic. It reads field instrument signals (inputs) and sends commands to field devices (outputs).

PLC (Programmable Logic Controller): Standard for discrete manufacturing, packaging lines, and most F&B/CPG. Dominant platforms: Rockwell Allen-Bradley, Siemens, Beckhoff.
DCS (Distributed Control System): Used for continuous process control — large-batch beverage, pharma, chemical. More expensive; better for highly interconnected analog control.
PAC (Programmable Automation Controller): High-capability PLC; Allen-Bradley ControlLogix is the dominant PAC in F&B/CPG.

Who provides it: The controls integrator designs the architecture, specifies hardware, procures it, and programs it. Major machine vendors (fillers, palletizers, packaging equipment) deliver their machine with its own pre-programmed PLC — these vendor PLCs must then be integrated into the plant-level system by the controls integrator.

Component	Typical Cost Range	Notes
PLC chassis + power supply	$2,000–$8,000	Per controller
I/O cards (16–32 points each)	$400–$1,500/card	Separate cards for DI, DO, AI, AO
Network communications cards	$500–$2,000/card	EtherNet/IP, Profibus per field bus
Control panel enclosure + hardware	$3,000–$15,000	UL 508A panel with distribution, terminals, cooling
Engineering labor — PLC programming	$8,000–$80,000	Largest variable; see cost drivers below

Estimator tip: PLC hardware is a small fraction of total controller cost. A $10,000 hardware panel can require $60,000–$100,000 in programming labor on a complex line. Proposals that show only hardware are incomplete.

Layer 3 — HMI (Human-Machine Interface)

The operator touchscreen mounted on the production floor. Shows a graphical view of the process; lets operators start/stop equipment, adjust setpoints, view alarms, and acknowledge faults.

Who provides it: The controls integrator develops plant-level HMI screens. Major machine vendors supply their own machine HMI.

Component	Typical Cost Range	Notes
HMI hardware (panel PC or dedicated terminal)	$1,500–$6,000 each	Allen-Bradley PanelView, Siemens, or industrial PC
HMI software license	$1,500–$5,000/seat	FactoryTalk View SE, Ignition, WonderWare InTouch
HMI screen development labor	$5,000–$40,000	Depends on screen count and process complexity

A typical packaging line HMI: 1–2 terminals, 20–60 screens, $15,000–$45,000 all-in.

Layer 4 — SCADA and Historian

SCADA (Supervisory Control and Data Acquisition): Plant-wide or area supervisory layer above the PLCs. Lets supervisors see the whole facility, view trends, manage alarms across multiple lines, generate reports — from a control room or remote workstation.
Historian: A time-series database that records process data (temperatures, flow rates, batch records, downtime events) for compliance, trend analysis, and OEE calculation. Often a separate server alongside SCADA.

Who provides it: The controls integrator. SCADA and historian aggregate data from all PLCs — they are plant-level scope, not machine-level.

Component	Typical Cost Range	Notes
SCADA software license	$5,000–$40,000	Ignition (subscription-free at server); FactoryTalk charges per client
SCADA server hardware	$5,000–$15,000	Industrial PC or rack server; redundant for critical applications
Historian software license	$5,000–$25,000	OSIsoft PI, FactoryTalk Historian, Ignition Tag Historian
Historian server hardware	$5,000–$15,000	Separate from SCADA server on larger sites
SCADA/historian development labor	$15,000–$80,000	Connecting all PLCs, building displays, configuring tags, alarm rationalization

Estimator tip: SCADA licensing is the most commonly omitted line item in a controls integrator proposal. An integrator who quotes SCADA “included” without naming the software platform and license tier is almost certainly under-scoped. Ask explicitly: what platform, what license tier, how many clients, is historian separate?

Layer 5 — MES and ERP Integration

MES (Manufacturing Execution System): Tracks production orders, work-in-process, batch records, genealogy, and quality data in real time between SCADA and ERP. Examples: Rockwell Plex, Parsec TrakSYS, Ignition MES modules.
ERP (Enterprise Resource Planning): The company’s business system — SAP, Oracle, Microsoft Dynamics. When a new line goes live, production data must flow to ERP so inventory reflects reality.

Who provides it: Almost never the controls integrator. MES/ERP integration is an IT and software project, managed by the owner’s IT department or a separate systems integrator. Almost never included in the construction GMP.

Estimator tip: Flag MES/ERP integration as an Owner Project Cost (OPC) on every estimate involving a new production line. Costs range from $50,000 for a simple data push to $500,000+ for full bidirectional ERP integration. See Owner Project Costs.

ISA-88 and ISA-95 — Why These Matter for Scope

You do not need to understand these standards in depth. You need to understand what they imply for scope definition and cost.

ISA-88: Batch Control Standard

ISA-88 defines how batch manufacturing processes are modeled and controlled. A batch process (mixing a recipe, brewing a tank, making a batch of sauce) has a defined start, a sequence of steps, and an end. ISA-88 provides a framework for structuring equipment hierarchies and writing batch recipes so the PLC executes them consistently.

Why it matters for estimating: When the owner invokes ISA-88 in their specification, they are requiring structured, modular PLC programming that follows the standard’s hierarchy. This is significantly more engineering work than unstructured ladder logic. It also requires:

A Functional Design Specification (FDS) written to ISA-88 structure before programming begins
Recipe management software (in the PLC system or a separate batch server)
More detailed FAT and validation testing

Cost impact: ISA-88-compliant batch systems cost 30–60% more in engineering labor than equivalent non-ISA-88 systems. If the project is food, beverage, pharma, or nutraceuticals and the spec mentions ISA-88, budget accordingly — and confirm the controls integrator has ISA-88 experience before awarding.

ISA-95: MES/ERP Integration Standard

ISA-95 defines standard models and interfaces for integrating plant floor systems (Layers 1–4) with business systems (ERP). It defines data structures for production scheduling, production performance, product definitions, and material movement.

Why it matters for estimating: ISA-95-compliant MES/ERP integration is not just connecting data — it requires mapping process data to the ISA-95 data model, a structured software development effort. This work:

Is almost always out of the controls integrator’s scope (belongs to the IT/MES integrator)
Requires interface specifications agreed to by both the controls integrator and the MES/IT team
Cannot be completed until PLC and SCADA are functional — it is always on the critical path during commissioning

Cost impact: ISA-95 integration adds $50,000–$300,000 to a project budget depending on ERP system, number of lines, and data requirements. This is an OPC, not a GMP cost, but the estimator should flag it.

Typical Cost Ranges by Project Complexity

Use these as a sanity check on integrator quotes — not as your primary pricing basis.

Project Type	Controls Integration Scope	Typical Cost Range
Single machine (standalone PLC + HMI, no SCADA)	1 PLC, 1 HMI, 100–300 I/O points	$30,000–$80,000
Single packaging line (multi-machine, line-level SCADA, no historian)	1–3 PLCs, 2–4 HMIs, 300–800 I/O points	$80,000–$200,000
Multi-line facility with plant SCADA and historian	5–15 PLCs, plant SCADA, historian, OT network	$200,000–$500,000
Complex batch facility (ISA-88, recipe management, full historian)	Multi-area PLCs, ISA-88 batch server, SCADA, historian	$300,000–$800,000
Greenfield plant with MES integration (ISA-95)	All of above + MES software, ERP interface	$500,000–$1,500,000+

Key cost drivers (in rough order of impact):

I/O point count — the number of field device connections is the single biggest driver of hardware and loop-check labor cost.
PLC program complexity — a simple conveyor sequence is 40 hours of programming; an ISA-88 batch unit with 15 phases is 400+ hours.
Number of PLCs to integrate — each additional PLC that must communicate with plant SCADA adds network configuration, data mapping, and testing labor.
SCADA/historian scope — how many tags, screens, historical data points, and what reporting is required.
FAT requirements — a formal witnessed FAT adds 20–40% to engineering labor.
Machine vendor PLC integrations — each machine vendor’s PLC requires a separate interface. Budget $5,000–$20,000 per vendor PLC integration.
Regulatory requirements — FDA 21 CFR Part 11, GAMP5 validation, USDA audit trails dramatically increase documentation and testing cost.

Cost Structure Breakdown

A well-structured controls integrator proposal breaks cost into these buckets. If these categories are not visible, ask for the breakdown before comparing bids.

Cost Category	Typical % of Total	What’s Included
Engineering labor — design	25–35%	Functional design spec, I/O list, network architecture, control narrative
Engineering labor — programming	25–35%	PLC code, HMI screens, SCADA configuration, historian tags
Hardware	15–25%	PLC chassis, I/O cards, panels, HMI terminals, network switches, servers
Software licenses	5–15%	SCADA, historian, HMI runtime, batch/reporting software
FAT / commissioning / SAT	10–20%	Testing labor at integrator facility + site; travel; integration support during startup
Documentation	3–8%	O&M manuals, as-built drawings, operator training

Rule of thumb: On a typical F&B/CPG line integration, hardware is ~20% of total, software licenses ~10%, and engineering labor 60–70%. A proposal heavy on hardware and light on engineering is underscoped.

How to Scope-Check a Controls Integrator Quote

When a controls integrator proposal lands on your desk, run through this checklist before leveling it against other bids.

What Should Be in Every Proposal

Common Scope Gaps — What Gets Missed

Gap Item	Why It Gets Missed	Typical Cost If Added Later
PLC program development labor	Integrator quotes hardware only; programs are “not yet defined”	$20,000–$100,000
SCADA software license	Quoted as “included” but license tier is insufficient	$5,000–$30,000
Historian	Not mentioned; assumed part of SCADA (often is not)	$8,000–$30,000
FAT support labor	Proposal covers design only; FAT is “additional”	$10,000–$40,000
Machine vendor PLC integrations	Each vendor PLC treated as a black box	$5,000–$20,000 per vendor
OT network hardware	Neither electrical sub nor integrator explicitly owns it	$5,000–$30,000
Remote access solution	Nobody asks for it; owner assumes it is standard	$3,000–$10,000
Operator training	Owner assumes their team will figure it out	$3,000–$15,000
21 CFR Part 11 / audit trail	Not mentioned until owner’s QA team reviews	$10,000–$50,000
Spare parts package	Not contractually required until handover	$5,000–$20,000

Estimator tip: When scope-checking bids, compare I/O point counts first. If Integrator A quotes 200 I/O points and Integrator B quotes 400 points for the same project, they are not pricing the same scope. Get both to state their I/O count in writing before leveling bids.

Controls Integration Sequencing

Controls work spans the entire project schedule and creates dependencies that affect the mechanical and electrical subs.

Phase 1 — Design (6–12 Months Before Startup)

Controls integrator develops the Functional Design Specification (FDS): defines what each control loop does, how alarms work, what the HMI shows, how the SCADA reports
I/O list finalized — shared with the electrical sub so they can size conduit and pull wire to the right locations
Network architecture developed — panel locations, IP addressing
PLC hardware specified and ordered — Allen-Bradley hardware lead times can be 8–20+ weeks; this procurement is on the critical path

Estimator tip: Controls hardware lead times are a project risk. Flag them in the schedule at BOE stage.

Phase 2 — Panel Build and Programming (4–8 Months Before Startup)

Controls integrator builds control panels at their shop (or panel fabricator builds to integrator’s design)
PLC programming and HMI screen development run in parallel with panel build — highest engineering labor phase
SCADA and historian configuration begins
FAT performed at integrator’s facility — owner’s team should attend

Coordination dependency: The electrical sub needs the I/O list finalized before purchasing instruments and scheduling pulls. If the controls integrator is late delivering the I/O list, electrical sub’s instrument procurement and installation is delayed — which pushes commissioning. This is one of the most common schedule risks on manufacturing projects.

Phase 3 — Site Installation and Pre-Commissioning (2–4 Months Before Startup)

Control panels delivered and set
Electrical sub terminates field wiring to panels per wiring schedule
Controls integrator performs loop checks: each I/O point is individually verified (signal from field device reaches PLC; PLC output drives field device)
Loop check labor: approximately 2–4 hours per I/O point. A 400-point system = 800–1,600 hours of site labor. Confirm who owns this.

Phase 4 — Commissioning and SAT (Final 4–8 Weeks Before First Production)

Equipment runs under PLC control; sequences tested against the FDS
PID loops tuned (flow, temperature, pressure, level)
SCADA tags verified against live data
Alarm rationalization — verifying every alarm is real, actionable, at the right priority
Operator training
SAT punch list worked and closed
System documentation handed to owner

Estimator tip: Controls commissioning cannot begin until mechanical completion. But it runs in parallel with process commissioning (CIP validation, equipment startup). The controls integrator must be on site at the same time as the mechanical and process commissioning teams. If you do not budget controls integrator site time during commissioning, you will have a change order.

Quick Reference: Who Owns What

Scope Item	Typical Owner
Conduit, wire, cable tray to field devices	Electrical sub
Field instrument mounting and wiring termination	Electrical sub
MCC panels, VFDs, starters	Electrical sub (furnish + install)
Control panel build (PLC chassis, I/O, enclosure)	Controls integrator (or panel fabricator per integrator design)
PLC programming	Controls integrator
HMI screen development	Controls integrator
SCADA/historian configuration	Controls integrator
OT network (switches, cabling between panels)	Negotiated — electrical sub runs cable; integrator configures switches
Machine vendor PLC integration	Controls integrator
Loop checks	Shared — electrical sub terminates; integrator verifies signal
FAT	Controls integrator runs; owner attends
SAT / commissioning	Controls integrator (on-site support); owner’s team operates
Remote access solution	Controls integrator or owner IT
MES/ERP integration	Owner IT or separate MES integrator

CSI Process Divisions 40-48 — how controls scope maps to Division 40 instrumentation
Scope Misses Checklist — controls integration items in the CPG/packaging checklist
Subcontractor Bidding and Bid Leveling — how to level controls integrator bids
Manufacturing Facilities 101 — process equipment context for what the controls system is controlling
FAT SAT and Line Acceptance — FAT/SAT scope and cost; controls integrator’s role in acceptance testing
Commissioning and Startup — where controls SAT fits in the commissioning sequence
Equipment Procurement and Lead Times — PLC hardware lead times and procurement risk
Owner Project Costs — MES/ERP integration as an OPC line item