Radio Design Labs ST-LCR3 Logic Controlled Relay – Dual Alternate Pulse
The ST-LCR3 is ideally suited to applications where momentary pulses are needed from a single control signal. The module provides a momentary pulse when a logic signal at its input first becomes active. A separate momentary pulse is provided when the logic signal at the module input becomes inactive.
Two logic inputs are available on the ST-LCR3. Either of these inputs may be used. Terminal 1 is internally pulled high to +5 Vdc. This input becomes active when an external closure or open-collector pulls the terminal to ground. The external switching device does not need to pull the terminal high, however the terminal may be pulled high with any voltage from +3.3 Vdc to +24 Vdc without any risk of damage to the ST-LCR3 input. Terminal 3 is internally pulled to ground. This input becomes active when an external closure or logic device applies a positive voltage from +3.3 Vdc to + 24 Vdc.
When the input being used first becomes active the START PULSE output from the module is triggered. When the input first becomes inactive (after first being active) the END PULSE output from the module is triggered. Both the start and end pulses have a nominal duration of 250 ms.
Each pulse output provides both an open-collector SLAVE terminal and relay contacts. The SLAVE terminal may be used to control other RDL modules and a variety of other equipment. The relay contacts may be used to control modules or equipment that do not operate from open-collector control.