SPR-24
Dual Solid State Pulse Isolation Relay

GENERAL DESCRIPTION

The SPR-24 dual repeating pulse isolation relay is designed to provide four isolated dry-contact, solid-state Form C (K, Y, & Z) outputs from two Form A or C inputs. Each output is mappable (assignable) to either of the two inputs, allowing a flexible configuration. The primary application for the SPR-24 is where two independent isolation relay channels are desired with multiple outputs on each channel, in one package.

The SPR-24 operates over the standard SSI wide voltage range. The SPR-24 has a built-in low voltage transformer-isolated power supply generating a +13VDC sense voltage. The sense voltage is sent to each electric meter's Y and Z pulse initiator output terminals from the SPR-24's Y1in1/Z1in and Y2in/Z2in input terminals, returning to the K1in and K2in terminals, the common return for both meters. Each output relay is switch selectable to follow (echo) one of the two inputs, thus allowing each input to control one, two, three or even four relays. Flexible configurations for the two input channels are possible: 0/4, 1/3, 2/2, 3/1, and 4/0 such that one SPR-24 may be used in lieu of two or more relays to accomplish the same task.

The SPR-24 may be used with electric meters having electro-mechanical or semiconductor output contacts, either high or low voltage. Typical applications include interfaces between utility metering devices and customer-owned energy control systems, demand recorder applications, and supervisory control systems (SCADA) interfaces. The SPR-24 relay is designed for high speed pulses and can switch up to 72,000 pulses/hour in 3-Wire mode and 36,000 pulses/hour in 2-Wire mode. The outputs are non-latching. The SPR-24 outputs' pulse timing follows the inputs' timing such that output pulses have the exact same pulse width as the input.

Bright red and green LED lamps, one on each input, indicates each channel's relay status at all times thus allowing a rapid check of the system's performance without requiring any additional test equipment. The SPR-24's input and output circuit's terminal strip is a "EURO" type connector strip. When the stripped wire has been correctly installed in the terminals "slot" no conductive parts are exposed on the surface of the terminal strip, thus allowing the user maximum protection from accidental electrical shock. Each "K" lead of the SPR-24's four outputs is fused to prevent damage to the relays under almost any conditions a user might cause such as excessive current, incorrect wiring, etc.

The SPR-24 has built-in MOV transient protection for the solid-state relay contacts which eliminates the need for external or off-the-board transient suppressors. All component parts which have power applied to them, with the exception of the input/output terminal strip are enclosed in a polycarbonate cover for maximum protection.

The mounting base plate is also made of polycarbonate and offers excellent electrical insulation between the circuits and the mounting surface. Inputs of the SPR-24 may be paralleled with other SPR-24, SPR-44, PCR-3 or DPR-22 relays to increase the number of available isolated outputs and functions.

SPR-24 SPECIFICATIONS

ELECTRICAL

Input	90 to 325 VAC. Burden: 10 MA. at 120 VAC
Signal Input	Two independent field selectable inputs, Form A or Form C. Each input has "Yin" and "Zin" terminals wetted- pulled up with +13VDC. "Kin" terminal is the common return. The Form A input uses the "Yin" terminal; The Form C input uses the "Yin" and "Zin" terminals for the input from the meter.
Output	Four sets of "dry" Form C contacts (K, Y, & Z) for energy pulses. The relay contacts are solid state with "no bounce" circuitry. Outputs are rated at 250VAC/VDC 1/10th Amp(100milliamps). Factory fused at 1/10 amp @ 250VAC. (3AG)
Contact Resistance	25 ohms maximum, 18 ohms typical
Insulation Resistance	50 megohms typical
Operate and Release Time	2 to 3 milliseconds typical
Input/Output Isolation Voltage	3750V

MECHANICAL

Mounting	Any position
Size	3.50 inches wide, 7.20 inches high, 1.50 inches deep
Weight	12 ounces

TEMPERATURE

Temperature Range	-38° C to +70° C, -36.4° F to +158° F
Humidity	0 to 98% non-condensing

OPTIONS

Input Voltages

125 VDC input using the DCS-1 Power Supply. Contact factory for other input voltages.