This zero signal detector module is designed to transfer the output relay contacts at any time the input signal exceeds the trip point setting. The trip point is symmetrical around the zero point, thus the output relay will pick up at the same point for both positive and negative input signals. Once the contacts transfer, they will remain so until the input signal returns below the trigger threshold. This module can be used in bidirectional applications to monitor the output and prevent a change in direction unless the system is stopped. It is also applied to monitor a command or feedback signal and shutdown the system or notify the operator should the signal drop below the threshold point.
This industrial grade module utilizes a stable reference and a precision full wave rectifier to maintain the preset trip points within 1%, as the ambient temperature and power supply are varied over the specified operating range. The relay pickup point can be adjusted from 1% to 10% of the rated signal range. A small amount of hysteresis is included to prevent relay chatter due to noisy or slowly changing input signals. Relay pickup and dropout at the trip point is may be delayed up to approximately 40 msec. The trip point adjustment control is mounted on the circuit board along with a visual indicator to show the output status. The output relay provides one form C contact. This module requires a bipolar 10 to 30 volt DC power supply for operation.
The circuit board is solder masked. All external connections are made to a barrier type terminal block with #6-32 captive wire clamping screws. All external connections and controls are clearly marked. The board can be mounted in the user's control enclosure on standoffs or located in plastic mounting track.
Applications: Zero signal detection with a relay contact transfer when the input signal exceeds the preset level. To prevent reversal unless the system is stopped. Detect signal loss.