External Relay Module for Overfill Prevention

The external relay module was introduced as part of the Titan Logix product line to support overfill prevention applications. The Finch 5332 display, when joined with the External Relay Module, provides a reliable solution for controlling higher-load devices in petroleum hauling applications and played a big role in providing safe, spill-free tank loading to this industry.

The 5332 display includes three relays that are activated by safety alarms, such as FILL, HH, and SPILL alarms. Each relay can be assigned to control external equipment, such as a horn, pump, or valve, when the corresponding alarm is triggered. Because the relays in the 5332 display are not designed to carry heavy loads for extended periods, the TTEXT-RLY provides the needed current capacity.

The Relay Module is designed to provide a fail-safe working environment while controlling the safe operation of the product pump or valve. The safety is a built-in system that requires all signals to be satisfied, or it will stop the rotation of the pump or close a valve.

Operation

The PTO signal turns the whole system on and is supplied by the front switch on the Finch 5332E display.

The PTO terminal in the Relay Module controls the first relay, K1, which provides a signal ground to the Fail-COM terminal.

The Fail-COM terminal provides the ground signal to the alarm loop, which consists of the SPILL and HH relays being jumper-wired together in a series arrangement. The HH-NC terminal controls the solenoid relay, K2. When the signal ground is present, the solenoid terminal will stay energized and allow fail-safe operation. Note: the fail-safe is that if power fails or is off to the 5332E system, then the pump will not work.

The system uses a loopback circuit. It is important to point out that the relay alarm signals being switched are ground signals and not power. The 12VDC power is connected to both relays, because only the ground signals are switched, except for the SOLENOID terminal which it is controlled by relay K2.

When the PTO is grounded, this energizes the first relay, which switches on the ground signal to the system loop. The ground signal exits the PTO relay and connects to the Fail-COM terminal. This terminal is wired to Fail-COM on the Finch 5332E. From FAIL-NC, it is connected to HH-COM. The loop signal goes through the HH relay from HH-COM to HH-NC and is wired back to HH-NC in the relay module. Please refer to the Basic Shutdown drawing. When the HH Alarm is reached the HH relay energizes and shuts down the pump by removing the voltage from the SOLENOID terminal.

The Fill or Fall relay is wired through to the relay module to keep the wiring centralized in the system. This relay is for a horn or lights and not the pump.

Relay Module (TT EXTRELAY)

Basic Shutdown Drawing Using TT EXTRELY Module