Product Description

The Quincy QLC 6-2 Logic Control consists of a wall mounted NEMA 12 Main Panel, NEMA 12 Interface Panels for each compressor, and a pressure transmitter (0-200 psig) for remote sensing of the control storage receiver pressure. The automation system is capable of operating up to 6 air compressors (virtually any brand or type) on a single pressure band in load/unload (two-step) mode by taking control of the compressors' start/stop and load/unload functions. The design enables you to maintain control storage pressure above a minimum desired level regardless of how many compressors are running. The control will keep only the compressors on-line that are necessary to satisfy plant demand. Compressors that are not needed are unloaded, timed out, and shut down. Local/Remote switches are included on the interface panels. The control utilizes the Allen Bradley 1500 Series Micrologix control platform which is compatible with A-B communication protocols.

Characteristics

The QLC 6-2 uses both pressure levels and changes in the demand airflow rates to determine which compressors need to be operating to support downstream air demand. It automatically loads, unloads and times out compressors, as needed. Normally, only one compressor will be trimming (Loading/Unloading). Run-Time, Last-in-First-out and First-in-First-Out sequencer control modes are available. Base and Trim compressor sequence control modes, which are also available, allow the control and rotation of different type or size compressors to be managed independently. The pressure control range is adjustable to fully utilize available receiver tank storage capacity.

The main panel comes with a 6" LCD, panel mounted, touch sensitive, backlit display. This panelview touch screen allows the operator to monitor the compressed air system, system pressure, status of each of the compressors and system setpoints.

In addition to the main panel there are Quincy Interface Panels for each connected compressor. If the switch on the interface panels is in the LOCAL position, it is assumed that the compressor is unavailable. The control of that compressor is accomplished by its onboard controls. The QLC includes an automation alarm status with dry contact output and fails to local compressor controls in all conditions which allows the compressors to protect the system pressure.

A shutdown log automatically records the date and time of the previous forty alarms. These include failure of a compressor to run, failure of a compressor to load and low system pressure alarm conditions.

Installation

This logic control is applied whenever efficient control of multiple compressors is desired. Interface panels are provided for each compressor to be automated to minimize intrusion on the compressor's controls and to simplify the field installation process. Information on the make, model, year of manufacture and control panel wiring diagrams is required when the order is placed. The customer is responsible for conduit and wiring between the main control panel and the interface panels, between the interface panels and the compressors, and between the main control panel and the pressure transmitter. For installer convenience and safety, the longer wiring runs from the automation panel to the interface panels and the system pressure transmitter have been designed to be 100% low-voltage (24vdc). The customer is also responsible for any additional parts required to upgrade existing compressor panels to permit remote start/stop and load/unload. A factory startup for final wiring terminations and control setup is required which typically requires 1-3 days, assuming all of the wiring is run ahead of time.

Optional Features:

Remote Communications: Both RS232 (50' max.) and RS 485 configurations are available. Modbus (Modicon), Modbus RTU and DF1 (Allen-Bradley) communications protocols are also available. Data address map information is provided to allow the customer to write the communications software program for his control.

Customization: The interface panels are easily customized to adapt to individual system requirements. For example, starting and stopping dryers in conjunction with the compressor.

Multi-Step Control: Options exist to allow multi-step control of reciprocating and centrifugal compressors.

Specifications:

Power Required - 110v dedicated circuit to main panel
Main Panel - NEMA 12 (30"Hx24"Wx12"D)
Interface Panel - NEMA 12 (16"Hx14"Wx6"D)
Pressure Transmitter

• Process Connection - ¼"NPTM
• Accuracy - +/- .25% full scale
• Range - 0-200 psig

Logic Controller

• Temperature Range - 0 - 150F
• Power - 24 VDC (prewired)
• Display - Backlit LCD