We recently carried out the physical replacement of an existing Trend IQ3/XCITE BMS with a Trend IQ500 controller and IQ5 I/O modules. The rip-out, installation and transfer of the existing wiring took approximately eight hours.

Alpha Controls was contracted for the site rip-out and retrofit only. We did not plan, design or supply the upgrade. The Trend hardware was free-issued by others, and several required accessories were missing. This is a record of the physical retrofit, not a claim that final power-up and commissioning are complete.

Existing Trend IQ3 equipment

The original Trend IQ3/XCITE controller and I/O modules were installed across multiple DIN rail rows and adjoining panel sections. Our Trend BMS systems guide explains the controller range. The replacement hardware comprised an IQ500, 16UIO, multiple 8UIO modules, an 8DO, and T1L adapters.

We retained the existing field wiring where suitable rather than rewiring all the sensors, actuators and outputs. Our legacy BMS retrofit-or-replace guide covers the wider upgrade options.

Original Trend IQ3/XCITE BMS panel before replacement.

Existing Trend XCITE input and output modules before removal.

Isolation and circuit labelling

The relevant electrical supplies were isolated and verified dead before starting the rip-out.

Before disconnecting anything, we identified the field circuits and labelled the outside of every removable connector. For the eight-point modules, we marked 1–4 across the top and 5–8 across the bottom, preserving the identification of the analogue and digital inputs and outputs.

We then transferred the wiring one circuit at a time. Labelling first avoided unnecessary guesswork during reconnection. This also matters on wider BMS wiring and integration projects.

Trend IQ3 to IQ5 hardware replacement

We removed the old equipment, mounted the new IQ5 modules on the existing DIN rails and transferred the field connections. The controller and I/O modules could not all sit together on one straight row, so we routed the inter-module connections through the existing trunking using Trend T1L adapters. See our Trend BMS upgrade services for related work.

We photographed the installation and recorded serial numbers privately for the job records; no serial numbers appear in the public images.

Trend IQ500 and replacement IQ5 I/O modules installed across three DIN rail rows.

Trend IQ500 controller with 16UIO fitted during the hardware retrofit.

Trend T1L wiring, screening and the 1-metre rule

The T1L terminals are marked 1 ground, 2 0V, 3 24V, 4 DA+, 5 DA− and 6 data cable screen. Terminal 6 is for the T1L communications screen, not for every field cable screen in the panel.

We checked the manufacturer's grounding instructions during the installation. For links under 1 metre within the same secondary enclosure, Trend permits the T1L ground connections to be linked. Over 1 metre, or between separate secondary enclosures, its separate local grounding arrangement applies. Our individual links were under a metre, but the bonding of the adjoining panel sections still needed to be considered.

We installed the additional grounding links using 1.0 mm² green/yellow cable. The connections and enclosure bonding still require verification before energisation.

Close-up of Trend T1L data-pair and cable-screen terminals.

Removable Trend IQ5 I/O terminal connectors following the field wiring transfer.

Where do the old IQ3 drain wires go on IQ5?

The original IQ3 had designated screen terminals for the field cable drain wires. The new IQ5 I/O modules do not have the same obvious termination point.

Those existing field cable screens require a separate DIN-rail screen terminal block, suitable sleeving and an appropriate connection to the panel's designated grounding point. They must not be bundled into T1L terminal 6.

The additional screen terminal block is still outstanding. We will fit it and complete the field screen terminations when we return.

Tools and materials used

The tool kit included a head torch, handheld torch, terminating chair, small terminal screwdriver, long screwdriver, side cutters, wire strippers, ferrule crimpers and Hellermann sleeving pliers.

Materials included 1.0 mm² green/yellow cable, Hellermann insulating sleeving, ferrules, pin crimps and terminal pins. The ferrules and pins must suit the conductor sizes and the terminals being used.

Outstanding equipment: 24V supply and blanking cover

The former IQ3 controller arrangement used a 230V supply; the IQ500 requires 24V. A suitable compact DIN-rail-mounted transformer or power supply is planned, but it had not been included in the free-issue equipment.

A blanking/end cover for the last module was also missing.

We are due back next week, subject to delivery, to fit the 24V supply, the dedicated screen terminal block and the missing cover. Supply capacity, protection, earthing and T1L loading will be checked before energising. Final testing and commissioning are separate from the eight-hour hardware changeover. Our BMS commissioning and graphics guide explains the subsequent system checks.

Trend 8UIO and 8DO modules installed in the adjoining panel.

Can a Trend IQ3-to-IQ5 retrofit be completed in a day?

Our physical changeover took approximately eight hours. That included isolation, identification, connector labelling, removal of the IQ3 equipment, installation of the IQ5 modules, field-wire transfers and working through the T1L arrangement.

For similar panels with reusable cables and all parts available, a one-day hardware retrofit may be achievable. That is different from promising a fully powered-up, configured and commissioned BMS in a single day.

For similar work, explore our BMS upgrades in London and BMS upgrades in Kent, or contact Alpha Controls about a Trend IQ3 replacement or IQ5 upgrade.