Dual-Channel Pulse Isolation Relay

SPR-22

The SPR-22 Pulse Isolation Relay by Solid State Instruments provides two fully independent channels, each delivering an isolated dry-contact solid state Form C (K, Y & Z) output from its own field-selectable Form A or C input. The solid state equivalent of the RPR-22PS, the SPR-22 is packaged in the compact SSI footprint enclosure and features a built-in low voltage transformer-isolated power supply that generates a +13 VDC sense voltage for each connected meter. It is compatible with electric meters having electromechanical or semiconductor pulse outputs, either high or low voltage.

The primary application for the SPR-22 is “Watts and Vars” metering, or any installation where two independent isolation relay channels are needed in a single package. Typical uses include interfaces between utility metering devices and customer-owned energy control systems, demand recorders, and supervisory control (SCADA) system interfaces. The SPR-22 supports high-speed pulse rates of up to 72,000 pulses per hour in 3-Wire mode and 36,000 pulses per hour in 2-Wire mode.

The SPR-22 Dual-Channel Pulse Isolation Relay on a white background.

Product Highlights

Each channel of the SPR-22 can be independently configured for either “long” or “short” output pulse mode. In long mode, the output pulse width mirrors the input exactly; in short mode, the output pulse is fixed at 100 ms — ideal for end-of-interval pulses or applications requiring a consistent pulse width. Non-latching outputs, per-channel LED status indicators, and input filtering circuitry that rejects noise pulses shorter than 18 ms ensure precise, reliable operation across both channels simultaneously.

The SPR-22 is built with the same proven safety and protection features found across the SSI product line. Built-in MOV transient protection eliminates the need for external suppressors, and each “K” output lead is individually fused at 1/10 amp to guard against excessive current or wiring faults. The “Euro” style terminal strip keeps all conductive parts safely recessed when wiring is properly installed, and the polycarbonate enclosure and mounting base plate provide excellent electrical insulation between the circuits and the mounting surface.

Features

The SPR-22 provides two fully independent isolated pulse output channels in a single compact enclosure.
  • Three sets of isolated solid state Form C (K, Y & Z) dry contacts from a single field-selectable Form A or C input
  • Purpose-designed for "Watts and Vars" metering and dual-channel isolation applications
  • Built-in transformer-isolated +13 VDC sense voltage supply for each input channel
  • Selectable long or short (fixed 100 ms) output pulse width per channel
  • High-speed operation up to 72,000 pulses/hour (3-Wire) or 36,000 pulses/hour (2-Wire)
  • Input noise filtering rejects pulses shorter than 18 ms to eliminate false triggers
  • Solid state contacts rated at 125 VAC/VDC at 100 mA with a maximum power rating of 800 mW
  • Built-in MOV transient protection on solid state relay contacts
  • Fused "K" output leads (1/10 amp, 3AG) on each output channel
  • 2,500Vrms input/output isolation voltage
  • Per-channel red and green LED status indicators for independent channel monitoring
  • "Euro" style terminal strip with no exposed conductive parts when wiring is properly installed
  • Operating temperature range of -38°C to +70°C (-38.4°F to +158°F)
  • Available with 125 VDC input using the DCS-1 Power Supply; contact factory for other input voltage options
The SPR-22 Dual-Channel Pulse Isolation Relay

Dual-Channel Independent Pulse Isolation

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