Illustrative scenario. It describes a typical situation, not a specific customer or project.
Staff accommodation (best fit)
The problem
A typical staff accommodation block houses residents who work rotating shifts. Rooms stand empty for long stretches while people are on site, and lights are often left on until the residents return. There is usually no key-card system and no one checking rooms during the day. A full guest room management system is rarely justified here.
The solution: one relay per room
Choose one of two relays for each room, never both:
- Option A: CRM-101/UNI. Wired to the room contactor, it switches off the room's supply once the room is empty. It has one 16 A changeover output, runs on AC/DC 12–240 V and takes 1 DIN module.
- Option B: CRM-102. New for 2026, it controls up to six lighting circuits directly through six 10 A zero-cross outputs. Each circuit has its own push button or standard switch, and a Master OFF button switches all of them off. It takes 2 DIN modules.
How it connects
The relay sits on a DIN rail in the distribution board. A magnetic door contact and a motion sensor connect to their own separate inputs. With Option A, the relay output drives the room contactor and the room keeps its existing switches. With Option B, the six lighting circuits connect directly to the relay outputs, and a push button or standard switch per circuit plus Master OFF connect to its button inputs. Logic (MODE) and delay (1–60 minutes) are set on the front panel with rotary switches: no programming, no app, software or network.
How it behaves
Opening the door restores power (CRM-101) or re-enables the light buttons (CRM-102). If the relay detects movement after the door closes, it stays on. If there is no movement, it switches off at the end of the delay. If a resident was asleep when it switched off, their first movement restores power or re-enables the buttons without delay.
Benefits
- Once a room is empty, the relay switches off what it controls (the room supply via the contactor, or the lighting circuits), and residents don't have to remember anything.
- No key cards are needed. Where cards are used, CRM-102 has a dedicated card-switch input; CRM-101 can be combined with a regular card switch.
- Each room works on its own, with no software, network or server to maintain.
- CRM-101 keeps the room's existing switches; CRM-102 adds a push button or standard switch per circuit plus Master OFF.
Hotel rooms
A typical mid-scale hotel or serviced-apartment building may want occupancy-based control without the cost and scope of a full GRMS. CRM-102 suits rooms with several lighting circuits, giving guests a push button or standard switch per circuit and a Master OFF, and its zero-cross switching is gentle on LED luminaires. CRM-101 suits simpler rooms where the goal is to switch off the room's supply through the contactor. The relays are standalone; for control from reception, app control or PMS integration, choose a GRMS such as iNELS GRMS.
Dormitories and student housing
A typical dormitory follows the same pattern: rooms are empty for much of the day. The same choice applies, with one CRM-101 per room for supply cut-off through the contactor or one CRM-102 for circuit-level lighting control.
Next step
To work out which relay fits your rooms, contact our sales team at sales@elkoep.qa or browse the ELKO EP Qatar eShop.