Retrofits & Upgrades

A systems integrator brings together equipment, robots, controls and software from several sources and makes them work as one system, often around existing plant. A machine builder designs and manufactures the machine itself, usually including the mechanical build. Many UK companies do both, so ask which disciplines are delivered in-house, which are subcontracted, and who takes single-point responsibility for the finished installation.

Describe the product and its variants, the process steps, the required throughput and quality criteria, the site layout and services, the interfaces to existing equipment and IT systems, your PLC, HMI, SCADA and safety standards, and the documentation, training and support you expect at handover. Set out acceptance criteria for FAT and SAT in the same document so quotations can be compared against the same measurable requirement.

There is no standard duration. Timescales depend on the scope of design, the number of disciplines involved, long-lead components such as robots, drives and controls, software complexity, and the site access available for installation and commissioning. Ask each supplier for a programme against your own requirement, with named milestones for design freeze, build, FAT, installation, SAT and handover, rather than assuming a typical figure.

Factory acceptance testing should prove the machine or cell against the agreed functional specification before it leaves the supplier: function, cycle behaviour, quality checks, changeover, alarms, safety functions and recovery from fault conditions. Site acceptance testing repeats the critical tests in the live environment with your own product, materials, services and operators, and adds the interfaces to upstream and downstream equipment. Agree both protocols in writing before order.

Decide this before contract, not at handover. Buyers who intend to maintain or modify equipment themselves usually require unlocked, commented source code for PLC, HMI, robot and vision applications, together with project files, licences, passwords and backups. Some suppliers offer restricted or escrowed code instead. Whatever is agreed, record ownership, access rights and the handover format explicitly in the quotation.

For new machinery placed on the market, expect a risk assessment, the safety functions and their required performance level or safety integrity level with supporting calculations, guarding and interlock details, the technical file, instructions for use, a declaration of conformity and the applied conformity marking. Where you are combining or modifying existing machinery, agree in writing who takes responsibility for the assembly. Marking and conformity rules change over time, so confirm the current Great Britain requirements at the point of order.

Normalise the scope first. Confirm each quotation covers the same design deliverables, disciplines, safety scope, controls platform, spares, documentation, training, FAT and SAT protocols, installation and commissioning, and aftercare. Then compare exclusions and assumptions, because that is usually where the real difference sits. Posting one project brief lets relevant supplier members respond against the same requirement, which keeps the comparison on equal terms.