Series-LTT

Supported Applications

The Dwyer Series LTT SSR Monitors are designed to monitor the operation of Solid State Relay (SSR) switches. The device compares input status with output status and triggers an alarm relay contact when specific fault conditions occur, including open load circuits or shorted SSRs.

• Monitors for loss of line
• Detects open loads
• Identifies shorted SSRs
• Maintains monitoring during DC power status checks (loss of DC power)

Operating Conditions & Performance

The Series LTT operates by comparing the trigger input against the load output to determine relay health. The monitors are configured for specific voltage ranges depending on the model:

• LTT12-0: 10 to 19 VDC Trigger, 100 to 660 VAC Load
• LTT24-0 and LTT24-1: 20 to 32 VDC Trigger, 100 to 660 VAC Load

Performance is indicated via an LED status indicator. The alarm output utilizes a normally closed dry relay contact rated at 200 VDC @ 0.5A max.

Mechanical and Installation Specifications

• Overall Dimensions: Height 2.500, Width 1.550 (units not specified in source)
• Mounting Method: Mounts on standard SSRs over the connection terminals with no additional hardware required.
• Cover Compatibility: Designed to fit under finger safe cover

Configuration Options

The Series LTT is available in three primary configurations distinguished by trigger voltage and diagnostic features:

• LTT12-0: Solid State Relay Monitor, 10 to 19 VDC Trigger, 100 to 660 VAC Load
• LTT24-0: Solid State Relay Monitor, 20 to 32 VDC Trigger, 100 to 660 VAC Load
• LTT24-1: Solid State Relay Monitor, 20 to 32 VDC Trigger, 100 to 660 VAC Load with Driver Circuit Test

All models share the same output signal specification: a normally closed dry relay contact rated at 200 VDC @ 0.5A max.

Key Product Differences

The primary distinction between Series LTT variants is the trigger voltage range and the inclusion of diagnostic testing capabilities:

• LTT12-0 supports a lower DC trigger range (10 to 19 VDC) compared to the LTT24 series.
• LTT24-0 and LTT24-1 both support a 20 to 32 VDC Trigger range with 100 to 660 VAC Load capability.
• The LTT24-1 model includes an additional Driver Circuit Test feature not present in the LTT12-0 or LTT24-0 descriptions.