Absolute Process Instruments Inc.,
API Signal Conditioning Products

Absolute Process Instruments Inc., has designed its API signal conditioning products with exclusive features which will prove invaluable during the equipment installation and start-up phases of a project. On transmitters, Absolute Process Instruments Inc., uses a series of LED's which we call LoopTrackers™ to monitor the presence and intensity of an input or output signal. The LoopTracker can be very helpful when checking for proper wiring and connection integrity. Bi-color LED's are used on alarm units to indicate relay status along with a special test button feature which allow an installer to toggle the alarm.

The LoopTracker LED's as a Diagnostic Tool

The API LoopTracker LED's track the input/output signal by varying its intensity with the process signal. As the signal increases the intensity of the LED increases and as the signal decreases the LED's intensity also decreases. Should a problem develop in the loop (i.e., a faulty device in the loop) causing an incomplete path for current, the LoopTracker detects this and ceases to illuminate. This function works on both the Input and Output loop allowing the technician to diagnose the cause of the problem quickly and efficiently therefore minimizing system downtime.

Functional Test Pushbutton

On Transmitters
The Functional Test Pushbutton on each API Transmitter will, when depressed, output a signal independent of the input signal. This signal is fully adjustable from 0-100% of span by holding the Test Pushbutton down and adjusting the "Test Cal." potentiometer on the unit.

This feature allows the technician to inject a Test or preset Calibration signal into the output loop without manipulating the input signal. This signal can be used to check loop status, downstream display operation, downstream alarm operation, etc.

For example, before the "Push-to-Test" button is pressed, the signal is: 4 mA input - 4 mA output. With the potentiometer set at 50% and the "Push-to-Test" button pressed, the signal is: 4 mA input - 12 mA output.

On Alarms
The Functional Test Pushbutton on each API Alarm will, when depressed, change the current state of the relays and Bi-Color LED's regardless of the input signal level. When released the relay will return to its normal operating state. An added feature of the Test Pushbutton is when depressed in the Latching Mode it allows manual reset of the latched alarm, provided an alarm condition no longer exists for that setpoint.

The Functional Test Pushbutton allows the technician to test the function of the relays as well as the operation of the device the relays are controlling. For example: an API 1000 G is used as a high level alarm to prevent the overflow of a wastewater tank. The relays are wired to a pump which, when a high level is detected, turns on and pumps the wastewater to an "overflow" tank. Since overflowing the tank to test the pump is impractical, the technician simply has to depress the Test Pushbutton and check the operation of the pump.

The Bi-Color LED's on API Alarms

The API Alarm family provides alarm status indication via a Bi-Color LED for each setpoint. The Bi-Color LED indicates Green for a Non-Alarm condition and Red for an Alarm condition whether or not the unit is configured for "Normal" (Fail-Safe) or "Reverse" (Non-Fail-Safe) acting. See following text for contact position and coil state in each of these conditions.

"Normal" (Fail-Safe) Relay Operation
In the "Normal" (Fail-Safe) mode of operation the LED will indicate Green for a Non-Alarm condition. In this non-alarm condition the relay coil is energized and the "C" and "NO" contacts are made. When the process signal crosses the preset setpoint the LED will indicate Red for an Alarm condition. In this Alarm condition, the coil de-energizes causing the "C" and "NC" contacts to be made. Should the alarm lose operating power due to a service interruption the coil will de-energize and fail to a "Safe" or Alarm condition.

"Reverse" (Non-Fail-Safe) Relay Operation
In the "Reverse" (Non-Fail-Safe) mode of operation the LED will indicate Green for a Non-Alarm condition. In this non-alarm condition the relay coil is de-energized and the "C" and "NC" contacts are made. When the process signal crosses the preset setpoint the LED will indicate Red for an Alarm condition. In this Alarm condition, the coil energizes causing the "C" and "NO" contacts to be made. Should the alarm lose operating power in the "Reverse" mode the coil will de-energize and fail to a "Non-Safe" or Non-Alarm condition.

Exclusive Standard Features

Listed below are exclusive features that are standard on all API alarm trips, isolators and signal conditioners:

• Lifetime warranty
• 2000 VRMS optical isolation
• Multiturn setpoint & deadband controls
• Field selectable HI/LO alarms
• Heavy-duty 7-amp relay contacts
• AC power
• True fail-safe alarm trips
• Industry-standard plug-in bases
• High-impact polycarbonate cover
• Glass epoxy PC boards
• Integral DC power supply to drive loop power device
• Adjustable deadbands for each setpoint on dual alarms

Remember, at Absolute Process Instruments Inc., there's never a factory calibration charge and there's never an expediting fee.

Options

• Reverse relay sense (non-fail-safe)
• Upscale/downscale burnout protection on T/C models
• Urethane conformal coating
• Faster response times
• High current outputs