SureLinx Series
Raycap SureLinx series (SLA2) are multi-stage surge protection devices developed for 24 V and 48 V, 4-20 mA electronic instruments. Featuring SAD + GDT hybrid technology, they provide low let-through voltage even during heavy surges, offering a 10 kA surge capacity. It is a maintenance-free, low-cost, and compact protection solution.
In industrial measurement and control systems, the 4-20 mA current loop is the standard method for transmitting signals from field instruments to the control system. These lines often cover long distances and pass through open areas, making them vulnerable to lightning-induced overvoltages. Damage to a transmitter or PLC input card can lead to production losses far exceeding the cost of the device itself.
The SureLinx SLA2 series is designed specifically for the protection of these lines. The device provides multi-stage protection for 24 V and 48 V DC powered 4-20 mA instruments.
The technical distinguishing feature of the series is its hybrid suppression technology: the device incorporates both a Silicon Avalanche Diode (SAD) and a Gas Discharge Tube (GDT). This combination leverages the strengths of both technologies—the GDT handles the bulk of the high-energy surge, while the SAD, with its fast response and low clamping voltage, reduces the residual voltage to a level tolerable by sensitive electronics. The result is low let-through voltage even during heavy surges.
The surge capacity is 10 kA (8/20 µs). A 4 Ω series impedance per line is the design element that ensures coordination between stages—it enables the correct operation of staged protection while creating a negligible voltage drop in the 4-20 mA loop.
The device is maintenance-free and easily mounted with screw terminal blocks. With dimensions of 72.5 × 39.5 × 38.7 mm and a weight of 45 g, it occupies minimal space in field enclosures and instrument panels. The housing is UL 94-V0 flame-retardant ABS plastic (indoor use). The wide operating temperature range of -40 °C … +80 °C is suitable for industrial field conditions.
The series consists of two models: SLA2-2024C (24 V) and SLA2-2048C (48 V).
- Multi-stage protection for 24 V and 48 V, 4-20 mA electronic instruments
- Hybrid suppression technology: SAD + GDT
- 10 kA (8/20 µs) surge current capacity
- Low let-through voltage even during heavy surges
- 4 Ω series impedance per line — inter-stage coordination
- Maintenance-free
- Screw terminal blocks (2-position) for easy installation
- Low-cost protection for electronic equipment
- Compact size: 72.5 × 39.5 × 38.7 mm, 45 g
- Housing: ABS plastic, UL 94-V0 flame resistance (indoor use)
- Wide operating temperature: -40 °C … +80 °C
Electrical Values
| SLA2-2024C | SLA2-2048C | |
|---|---|---|
| Nominal DC operating voltage | 24 V | 48 V |
| Max. continuous operating voltage MCOV | 28 V | 56 V |
| Max. continuous operating current MCOC | 4-20 mA loop | 4-20 mA loop |
| Max. surge current capacity Imax | 10 kA (8/20 µs) | 10 kA (8/20 µs) |
| Suppression technology | SAD & GDT | SAD & GDT |
| Series impedance per line | 4 Ω | 4 Ω |
Mechanical & Environmental
- Connection (suppression): wired, #16 – #22 AWG
- Terminal type: 2-position screw terminal block
- Operating temperature: -40 °C … +80 °C
- Housing type: ABS plastic, UL 94-V0 (Type 1, indoor use)
- Dimensions (L×W×H): 72.50 × 39.50 × 38.74 mm
- Weight: 45 g
The SureLinx series is used for the protection of 4-20 mA signal and low-voltage DC instrument lines:
- 4-20 mA current loop lines — Between field instrument and control system
- Pressure, temperature, and level transmitters — Protection of field measurement devices
- PLC and DCS analog input cards — Protection at the control system side
- Instrumentation panels — Signal aggregation points
- Light industrial facilities — Process measurement infrastructures
- Telecommunication applications — 24 V / 48 V DC signal lines
- Long cable routes — Lines with increased induction risk in open areas
- Water and wastewater facilities — Remote pump station instrumentation
- Energy and infrastructure facilities — Remotely monitored measurement points
- Sites requiring maintenance-free operation — Hard-to-reach points for periodic service
- Cost-sensitive projects — Economical protection for numerous measurement points
- SureLinx SLA2 Series Datasheet Download
