General Assist Technical Reference
VRF System Controller & UTY-PEGX
Electricity Charge Apportionment, kWh meter integration, commissioning and troubleshooting
For VRF sites using System Controller with UTY-PEGX
This article provides a practical guide to deploying and administering the VRF System Controller and UTY-PEGX. It covers controller architecture, Electricity Charge Apportionment (ECA), pulse kWh-meter integration, remote access, permissions, commissioning and troubleshooting.
Qualified personnel only: Electricity metering can involve mains voltage, current transformers and external control wiring. Electrical work must be completed in accordance with the applicable site requirements and manufacturer documentation.
1. Architecture at a glance
| Area | Description |
|---|---|
| Networks & Groups | Remote Controller Groups, RB Groups and Outdoor Unit Groups. |
| Control Scope | Central monitoring and operation of indoor units, schedules, energy apportionment, alarms and reporting. |
| Energy Model | Outdoor unit energy is measured; indoor-unit allocation is calculated by the controller logic. |
Roles and responsibilities
- Project / Commissioning Lead: Defines contracts or tenant areas, sets controller time and validates energy totals.
- Controls Technician: Wires pulse inputs, programs meters and constants, sets ports and security.
- Site Owner / Facility Manager: Reviews reports, billing outputs and long-term trends.
2. Electricity Charge Apportionment (ECA)
Objective: Allocate energy fairly to tenants or zones.
Primary inputs:
- Contract definitions and mapped equipment groups.
- Pulse counts from kWh meters, converted to kWh using the meter constant.
- Controller rules for distributing standby energy and handling communication exceptions.
Golden rules for ECA mapping
- Do not split a Remote Controller Group across different meters.
- Do not split an Outdoor Unit Group across different meters.
- RB Groups may be divided where required.
- Each meter must align to one contract only.
3. kWh meter integration - pulse input
Typical hardware: kWh meter with pulse output, CTs and VT/PT where required, shielded pulse cable and the System Controller external-input harness.
| Item | Requirement |
|---|---|
| Pulse output | Dry-contact or transistor/photo-coupler output with defined pulse width and frequency. |
| Pulse unit / constant | Program either a pulse unit such as 1, 10 or 100 kWh per pulse, or a pulse constant in pulses per kWh. |
| CT / VT ratios | Enter the installed ratios in the meter where applicable. |
| Pulse wiring | Confirm polarity and shielding of the pulse pair. |
Best practice
- Use one meter per contract boundary.
- Keep pulse runs short, segregated from mains and correctly terminated.
- Run a timed-load test and compare the meter register with the pulse count seen by the controller.
4. Outdoor unit and controller parameters
Outdoor Unit - electricity meter settings
- Assign the Meter No. and select the pulse type - unit or constant.
- When using a pulse unit, match the controller pulse-to-kWh value.
- When using a pulse constant, enter the integer value at the outdoor unit and the full decimal value at the controller where supported.
System Controller / UTY-PEGX
| Setting area | Required action |
|---|---|
| Initial settings | Set date/time and language, scan communications and confirm electricity meters are detected. |
| Zone settings | Map electricity-meter zones to the correct outdoor groups. |
| ECA settings | Create contracts, assign groups, enter pulse constants or units and configure standby-energy allocation. |
| Reporting | Verify daily and period totals and generate the appropriate site billing or summary output. |
5. Remote access and security
- Port numbers: Configure distinct ports where multiple controllers are installed.
- User roles: Use named user IDs with least-privilege access such as monitor, operator and administrator.
- Change control: Record the commissioned configuration baseline and save a backup.
- IT coordination: Confirm firewall rules match the required port assignments and disable unused services.
6. Commissioning checklist
Before power-up
- Verify CT polarity, VT ratio where used, pulse polarity, shield continuity and earthing.
- Confirm controller addressing and physical group mapping.
Controller setup
- Set system time and time zone.
- Scan devices and confirm all indoor units, outdoor units and meters are online.
- Enter the meter pulse unit or constant and assign each meter to the correct contract.
Validation
Timed-load test: Run a stable load for a defined period and compare the physical meter register kWh with the controller-counted kWh. Differences should be investigated before handover.
- Confirm contract totals and preview a trial bill or equivalent site summary.
- Check alarm and communication pages for errors and resolve them before handover.
Handover
- Provide operator training covering schedules, overrides and reports.
- Save and archive the configuration backup and commissioning report.
7. Troubleshooting guide
| Symptom | Checks |
|---|---|
| No pulses counted | Check pulse wiring, polarity and output type; confirm the meter output is enabled and the controller input is mapped correctly. |
| Totals too high or too low | Re-enter pulse constants, confirm CT/VT ratios and check for split groups or cross-contract wiring. |
| Intermittent data gaps | Inspect indoor/outdoor communication, controller time synchronisation and power stability. |
| Standby allocation concerns | Review standby distribution settings and confirm outdoor-group alignment with contracts. |
| Remote access failure | Validate port configuration, firewall rules and user permissions. |
8. Operator tips
- Maintain a site map showing contract boundaries, meter numbers and controller input labels.
- Review ECA totals regularly against expected tenant usage.
- After any equipment or metering change, re-validate pulse constants and group mapping.
9. Key points
- Align meters with the correct groups and contracts.
- Program pulse data consistently in both the outdoor unit and the controller.
- Validate the system with a timed-load test before handover.
- Use appropriate user permissions and maintain a current configuration backup.
General Assist Technical Reference