General Description

Vital Relays have traditionally been a mainstay for switch machine control in the field. While they have established a history of reliable performance, vital relays require periodic maintenance for this degree of reliability to be achieved. Ansaldo STS has developed a cost-effective, yet equally reliable, alternative. The SML-24 Switch Control and its companion module, the SMC controller are designed for low voltage applications and the SML-110 along with the PN-150SSR can be used in high voltage switch machine applications.

Both the SML-24 and the SML-110 can control up to two switch machines simultaneously. The SML-24 uses both 24 Vdc and 12 Vdc power sources and a 12 volt “lock” gating signal. The SML-110 delivers a nominal 120 Vdc output with a limited current of 23 amps from AC or DC sources when activated by a nominal 12 Vdc output. To deliver an output voltage, the SML requires the presence of two out of three inputs: Switch machine lock and either the normal or the reverse switch request. The input can originate from relay contacts or a vital interlocking processor such as MicroLok® II or other vital controllers.

Benefits

• SML incorporates internal overload thermal protection to enable it to withstand continuous short on the output, replacing the functionality of existing overload relay

• Reduced cost when compared to equivalent vital relay control

• Eliminates various switch machine electro-mechanical relays

• Can simultaneously operate two switch machines

• Designed to operate 2, 3, or 5 wire controlled switch machines

• Interfaces to Ansaldo STS MicroLok II, or any vital interlocking controller

Product Design

The SML is contained in an assembled sheet metal housing designed for mounting on standard equipment rack relay mounting bars. Typically, the unit is mounted with a combination rack mounting plate/AAR terminal board that provides AAR terminals for external wiring. The SML unit may be mounted adjacent to the controlling vital system without creating “noise” problems in logic or I/O wiring.

A 12-pin male connector on the rear of the unit permits plug connection of the SML unit to the rack mounting plate. Major subassemblies inside the SML are mounted on a chassis shelf or are attached to the underside of the aluminum heat sink. Components are readily accessed by removing a one-piece, wrap around shell on the housing. A single LED on the front panel of the unit indicates the presence of output power to drive the switch machine.

SML-24 AND SML-110 SWITCH LOCK

www.ansaldo-sts.com

Specifications

© 2014 Ansaldo STS USA, Inc.MicroLok II is a trademark of Ansaldo STS USA, Inc.

SML-24

Input Voltage 24 Vdc to 36 Vdc

Output Voltage/Current 24 Vdc @ 35A (max.)

Dielectric Withstanding Voltage

2000 V ms

Short Circuit Protection Built-in; set to 41A

Max. Wiring Distance

SML to switch machine 500 ft. using 1000 ft of #6 wire at 0.42W/1000ft. producing a 9.7V drop @ 23A

24V Supply, 24V Output Wiring: #6 TC blue or equivalent

Operating temperature -40° C to +70° C

SMC

Input Control Voltage 9.8 Vdc to 16.2 Vdc

Output Voltage/Current 24 Vdc @ 35A (max.)

Operating Temperature -40° C to +70° C

SML-110

Input Voltage 90 Vdc to 130 Vdc; 90 to 140 Vdc

Output Voltage 125 Vdc (current limited to 23A)

Input-to-Output Isolation 2000 V rms

Short Circuit Protection Built-in; set to 23A

Wiring Distance 500 ft. (max.) 1000 ft of #6 wire at 1.0 ohms/1000 ft., producing a 24V drop @ 15A

110V Supply, 110V Output Wiring: #12 TC blue or equivalent

Internal Shut-Off Timer 14 to 20 sec.

Operating Temperature -40° C to +70° C

Ordering Information

To order the Ansaldo STS SML Switch Lock, please contact your Account Manager or Customer Service at 1-800-652-7276.

Part Numbers:

SML-24: N47300701SMC: N49800901SML-110: N47302301PN-150SSR: N40103601

Ansaldo STS USA, Inc.

1000 Technology DrivePittsburgh, PA 15219-3120 USAtel + 1.800.351.1520fax + 1.412.688.2399email: sales@ansaldo-sts.uswww.ansaldo-sts.com