Insulation Fault Locator ISOM DLD440-12 Socomec
47964402
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The ISOM DLD440-12 is an insulation fault locator for industrial IT networks. It monitors 12 channels simultaneously (AC 0-1000V / DC 0-1500V) and pinpoints the faulty circuit, including transient faults and high-resistance faults. Works in conjunction with the ISOM ALD395 or ALD495 monitoring unit. Compliant with IEC 61557-9.
- 12 channels — simultaneous scanning, no sequential delay
- Universal supply voltage 24-240V AC/DC
- Differential current range 100 mA to 20 A
- IS bus: up to 21 modules / 1,200 m
- PLC/SCADA integration via 0/20 mA output
Technical Description
The ISOM DLD440-12 (Socomec reference 47964402) is an insulation fault locating device designed for industrial IT (ungrounded) networks. Its role is to determine precisely, among the 12 connected circuits, which one is affected by a first insulation fault — including transient faults and high-resistance faults that standard measurement methods cannot reliably detect.
The DLD440-12 operates as part of a complete ISOM system. It receives the search signal injected by the ISOM ALD395 or ALD495 monitoring unit, detects it through DLD-type current transformers fitted on each outgoing circuit, and identifies the faulty feeder. Simultaneous scanning of all channels eliminates sequential analysis delays.
It covers AC networks 0-1000V (single-phase and three-phase) and DC networks 0-1500V (applicable to industrial photovoltaic installations and battery systems). The device's own supply accepts 24-240V AC or DC. The configurable 0/20 mA digital output enables integration with a PLC or SCADA system.
Technical Specifications
| Parameter | Value |
|---|---|
| Manufacturer reference | 47964402 |
| Model | DLD440-12 |
| Product family | ISOM DLD — Socomec |
| Supply voltage | 24-240 VAC / VDC |
| Number of monitored channels | 12 |
| AC network voltage range | 0 to 1,000 V |
| DC network voltage range | 0 to 1,500 V |
| Differential current IΔL | 100 mA to 20 A |
| Frequency range | 42 Hz to 1 kHz |
| Fault types located | Transient faults, high-resistance faults |
| Communication bus | IS bus (Bender IS) |
| Max. modules per bus | 21 DLD units |
| Max. bus length | 1,200 m |
| Digital inputs | Configurable (test, reset) |
| Digital output | 0 or 20 mA (PLC input) |
| Associated monitoring unit | ISOM ALD395 / ALD495 |
| Compatible CTs | Socomec DLD-type current transformers |
| Standard | IEC 61557-9 |
| Carbon footprint (cradle-to-grave) | 172 kg CO₂ eq. |
DLD440-12 vs DLD240-12 — Which Model to Choose?
| Criteria | DLD440-12 (this product) | DLD240-12 |
|---|---|---|
| Socomec reference | 47964402 | — |
| Primary application | Main power circuits — industrial distribution | Control circuits, medical locations |
| Differential current IΔL | 100 mA to 20 A | 100 mA to 2 A |
| Frequency range | 42 Hz to 1 kHz | 50/60 Hz only |
| Network voltage range | AC 0-1000V · DC 0-1500V | AC 0-1000V · DC 0-1500V |
| Number of channels | 12 | 12 |
| Tropicalized version | DLD440-12W (ref. 47964403) | DLD240-12W |
Selection rule: for industrial distribution (main switchboards, process panels), choose the DLD440-12. For low-power control circuits or medical installations (operating theatres, treatment rooms), the DLD240-12 is the appropriate choice.
Frequently Asked Questions
What is the ISOM DLD440-12 used for?
The ISOM DLD440-12 is an insulation fault locator for industrial IT networks. Once an insulation monitoring device (ISOM ALD395/495) has detected a first insulation fault on the IT network, the DLD440-12 precisely identifies which of the 12 connected circuits is affected — including transient faults and high-resistance faults. Without a locator, the technician must disconnect each feeder one by one to find the faulty circuit, causing uncontrolled production downtime.
Can the DLD440-12 be used on a photovoltaic DC network?
Yes. The DLD440-12 covers DC networks up to 1,500V, making it suitable for industrial PV installations and battery storage systems. It must be paired with a compatible INJ injector and the ISOM ALD495 monitoring unit. IEC 61557-9 applies to this configuration. Contact our technical team for application-specific guidance.
How many DLD440-12 units can be connected to the same IS bus?
The system supports up to 21 DLD modules on a single IS bus, with a maximum cable length of 1,200 m. Each DLD440-12 monitors 12 channels, enabling surveillance of up to 252 circuits on a single ISOM system. DLD240-12 modules can coexist on the same bus.
Which monitoring unit should be paired with the DLD440-12?
The DLD440-12 connects to the Socomec ISOM ALD395 (standard version, local display) or ISOM ALD495 (extended display, Modbus RS485 communication). The monitoring unit generates the injection signal; the DLD440-12 detects this signal through the DLD current transformers and identifies the faulty feeder. Without an ISOM monitoring unit, the DLD440-12 has no standalone function.
How do I integrate the DLD440-12 into a SCADA system?
Integration is achieved via the configurable 0/20 mA digital output on each channel, which can be wired to a PLC analogue input. For full data remoting with channel identification and measurement parameters, the ISOM ALD495 with Modbus RS485 communication is recommended. Contact our team for Modbus mapping support: +33 1 43 44 60 00.
