Machine retrofit and modernisation
Most production machines fail long before they wear out. The mechanics are sound, the frame is rigid, the tooling still holds tolerance — but the controller has been out of production for a decade, the operator panel has a dead backlight, and the last person who knew the program left the company. Machine retrofit and modernisation means replacing the control layer of a mechanically healthy machine: a new PLC, a new HMI panel, drives, wiring, a rebuilt visualisation with the original recipes, and safety functions brought up to current standards. The machine keeps doing what it did before, for a fraction of the price of a replacement.
Automation Dariusz Kulik is an industrial automation integrator based in Poland, with fifteen years of practice and projects delivered throughout the country. Retrofit work begins with a site visit and an assessment of what genuinely has to be replaced — which is often less than expected. A quotation follows within 48 hours of that visit. Where the decision between a retrofit and a new machine is not obvious, it is worth reading the comparison of retrofit against buying new before committing to either.
Diagnosis before replacement
A retrofit starts with establishing what the machine actually does, not what its documentation claims. The existing program is read out and archived wherever the controller still permits it — this is frequently the only surviving record of the process logic, and once the old CPU is removed it is gone for good. Where the source has been lost or is password-protected, the sequence is reconstructed from observation of the running machine, the wiring, and the operators who use it daily.
The assessment then separates the control system into parts that must go and parts that may stay. A failed operator panel does not oblige anyone to replace a functioning controller. Equally, a controller with no spare parts on the market is a liability even if it currently runs. Sensors, motors and gearboxes are usually retained. The guidance in where to start with production automation applies as much to a single retrofitted machine as to a greenfield installation.
Control equipment and communication
Panel and controller selection follows the process, not the catalogue. Xinje TS series panels cover the majority of retrofit cases: the TS5-700-E offers a 7-inch 800×480 display and the TS5-1000-E a 10.1-inch 1024×600 display, both built on a 1 GHz Cortex-A7 with 128 MB of memory, resistive touch, IP65 protection at the front and a 24 V DC supply. Connectivity comprises COM1 (RS232/485), COM2 (RS232/485/422) and an RJ45 Ethernet 10/100 port supporting Modbus TCP; projects are developed in TouchWin Pro. Wider selection criteria are set out in the guide to choosing an operator panel and, for the controller itself, in the PLC selection guide.
Two constraints deserve early attention. Where a new panel is to talk to an existing Siemens S7-1200 or S7-1500, PUT/GET communication must be enabled in the CPU’s protection settings and the data blocks being read must be non-optimised — otherwise the connection simply will not establish, whatever the panel side is doing. And in an explosive atmosphere a standard operator panel is inadmissible regardless of its IP rating; the enclosure protection class says nothing about ignition risk, and the equipment must be certified for the zone.
Safety functions and legal status
Safety functions are implemented by a safety relay or a safety controller, including over industrial networks such as PROFIsafe, CIP Safety or FSoE. A hardwired circuit is not the only admissible option, and networked safety is often the more maintainable one on a machine with distributed stations. What is fixed is the emergency stop device itself: EN ISO 13850 requires a manually actuated device with latching and direct opening action, which no touchscreen can ever satisfy. The stop command may be transmitted over a safety network; the actuator remains a physical mushroom-head button.
Regulation (EU) 2023/1230 applies from 20 January 2027 and replaces Directive 2006/42/EC. The question of whether a retrofit constitutes a substantial modification turns on change in risk, not on throughput or speed — a machine made faster without altering its hazard profile is treated differently from one whose guarding or access pattern has changed. A notified body is involved only for high-risk categories. The regulatory position is established during the assessment, before any work is quoted.
Scope of work
- Site visit, condition assessment of the control system and identification of components that must be replaced
- Read-out and archiving of the existing program before any equipment is removed
- Selection and supply of the PLC, operator panel, drives and control cabinet apparatus
- Replacement of wiring, cabinet rebuild and reconnection of field devices
- Rebuilt visualisation reproducing the original screens, alarms and recipe sets
- Safety functions on a safety relay or safety controller, with the emergency stop chain verified
- Commissioning, trial production, operator training and handover documentation
Indicative budget and lead time
A retrofit of a single machine typically falls between PLN 30,000 and 50,000 (approximately EUR 7,000–12,000). A semi-automatic machine ranges from PLN 50,000 to 150,000 (approximately EUR 12,000–35,000), a robotic workstation from PLN 150,000 to 500,000 (approximately EUR 35,000–115,000), and a full production line retrofit from PLN 80,000 to 400,000 (approximately EUR 19,000–95,000). Return on investment falls in the range of 12 to 36 months, and 12 to 24 months for a well-chosen first project. Lead times from contract to handover are 1–3, 2–4 or 3–6 months depending on scale. The method behind these figures is set out in the cost and ROI analysis.
Example from our projects
A dairy lost the operator panel on its CIP station — the cleaning system on which the whole plant’s hygiene regime depends. The damaged Siemens panel was replaced with an Xinje TG and the visualisation rebuilt identically, so that operators saw no difference in how the station was run. The existing S7 controller was left untouched and PROFINET communication retained. The work was completed in under a week at a cost saving of around 70% against a like-for-like replacement.
Where a retrofit extends to new mechanics and motion control, the same approach applies — the semi-automatic shaver head assembly machine combines an Xinje TG HMI with an Xinje DS2 servo drive accurate to tenths of a millimetre, delivering a threefold throughput increase with zero defects and settings changed from the panel without a programmer.
Frequently asked questions
Does the whole control system have to be replaced at once?
No. The dairy CIP station is the clearest illustration: only the operator panel was replaced, the S7 controller stayed in place and PROFINET communication was retained. Partial retrofits are the normal case where the remaining equipment is supported and spare parts are obtainable. A full replacement is justified when the controller is obsolete, unsupported, or so tightly coupled to failed I/O that separating the two costs more than replacing both.
What happens if the original program cannot be recovered?
The sequence is reconstructed from the machine itself — from the wiring, the field devices, observation of the running process and the knowledge of the operators. This lengthens the analysis stage but does not prevent the retrofit. It is one reason why archiving is carried out before any equipment is removed: an unread controller that is powered down may never give up its contents again.
Can the emergency stop be placed on the touchscreen?
It cannot. EN ISO 13850 requires a manually actuated device with latching and direct opening action, and a touchscreen satisfies none of those three properties. The safety function behind it may be implemented on a safety relay or a safety controller and may be carried over an industrial network such as PROFIsafe, CIP Safety or FSoE, but the actuator itself must remain a physical device.
Does a retrofit require a new CE conformity assessment?
It depends on whether the work constitutes a substantial modification, and the test for that is change in risk — not an increase in throughput or speed. Regulation (EU) 2023/1230 applies from 20 January 2027 and replaces Directive 2006/42/EC. A notified body is involved only for high-risk categories. The position for a given machine is determined during the assessment, so that any conformity obligations are known before work begins rather than discovered afterwards.
Request a quote
If a machine on your floor is held back by its control system rather than its mechanics, arrange a site visit. We will look at what you have, tell you what has to be replaced and what can stay, and send you a quotation within 48 hours of that visit. Call +48 796 019 414 or write to biuro@automation.net.pl — briefly describing the machine, its controller and what has failed will let us give you a useful answer straight away. You can also send your enquiry via the contact form.