Action Pak models AP1280 and AP1290 limit alarms offer wide ranging input and flexible setpoint capability. They accept six popular thermocouple types with inputs ranging from -270°C (-450°F) to 3200°C (5800°F). The AP1280 provides a single-setpoint alarm while the AP1290 provides two independent setpoint alarms. The AP1280 and AP1290 also include 0.25%-50% adjustable deadbands and selectable 120/240VAC operation.
Models AP1280-2000 and AP1290-2000 are equipped with dual function diagnostic LED. The green center LED indicates line power and input signal status. Active line power is indicated by an illuminated LED. If the center LED is off, check line power and the wiring connection. If the input signal is above 100% full scale, the LED will flash at approximately 8Hz. Below 0%, the flash rate is approximately 4Hz.
The field configurable AP1280 and AP1290 limit alarm setpoints can be configured for HI, LO, latching or failsafe trip operation. Non-latching HI and LO setpoints have respective HI and LO deadbands. In a tripped condition, the setpoint is exceeded and the appropriate red LED will illuminate. The trip will reset only when the process falls below the HI deadband or rise above the LO deadband. To reset a latched setpoint the signal must be in the safe region and the line power turned off for at least 5 seconds. For proper deadband operation, a HI setpoint must always be set above a Lo setpoint.
Note: To maximize thermal stability, final calibration should be performed in the operating installation, allowing approximately 1 - 2 hours for warmup and thermal equilibrium of the system.
Setpoint: Set deadband at its minimum (about 20 turns Counter Clockwise) before adjusting the setpoint. With the specified trip voltage or current input applied, adjust setpoint until the relay trips. For HI trip calibration, start with the setpoint above the desired trip. For LO trip calibration, start below the desired trip.