The HPA-75-ENC is equipped with an AirMaster Q2 Programmable Logic Controller (PLC) that manages all aspects of system operation — including start/stop control, pressure monitoring, auto drain sequencing, service hour tracking, and alarm logging. This article covers the controller interface, menu structure, operating modes, and key parameter access for operators and service technicians.
Control Panel Overview
The AirMaster Q2 controller features a graphic display screen with a physical keypad. The display shows real-time system status, pressure readings, service timers, and alarm information. All navigation is performed using the keypad buttons described below.
AirMaster Q2 Controller — Front Panel View
Keypad Button Functions
| Button | Function |
|---|---|
| Start (I) | Starts the compressor |
| Stop (O) | Stops the compressor |
| Reset | Clears active alarms after the fault condition has been resolved |
| Enter | Confirms a selection or drills into a menu item |
| Up (▲) | Scrolls up through menu pages or increases a value |
| Down (▼) | Scrolls down through menu pages or decreases a value |
| Escape (C) | Returns to the previous menu level or cancels an entry |
Graphic Display Layout
The main display (P00) is the default home screen. It shows compressor position, current pressure, operating mode, and system status. After a period of inactivity the display backlight will dim — press any key to restore it. The display will always return to P00 after a period of no keypad activity.
AirMaster Q2 — Main Display Screen Layout
The display is divided into three zones across the top: operating mode on the left, current pressure reading in the center, and compressor status on the right. Below this, the active menu page name and page number (e.g., P00) appear, followed by scrollable menu content items.
Menu Navigation
Menu pages are arranged sequentially from P00 through P08 in a continuous loop. Use the Up and Down keys to move between page numbers when the page tab is highlighted. Press Enter to drill into a page and access its content items. Press Escape to return to the previous level. The current navigation position is indicated by an inverted highlight on the display and a marker on the vertical scroll bar.
Menu Structure Reference
P00 — Main / Home Screen
| Parameter | Description |
|---|---|
| P00.01 | Active alarm or error |
| P00.02 | Operation mode — control mode and load/off-load status |
| P00.06 | 1st stage pressure |
| P00.07 | 2nd stage pressure |
| P00.08 | 3rd stage pressure |
| P00.20 | Purifier (HP receiver) pressure |
| P00.21 | Oil pressure |
| P00.22 | Inlet temperature |
| P00.23 | Outlet temperature |
| P00.24 | Inlet pressure |
P01 — Service and Machine Hours
| Parameter | Description |
|---|---|
| P01.01 | Total output hours since production |
| P01.02 | Total load and idle time combined |
| P01.03 | Total time on load |
| P01.04 | Total idle time |
| P01.05 | Total stop time |
| P01.06 | Time remaining until purifier filter change |
| P01.07 | Time remaining until oil change |
| P01.08 | Time remaining until valve and segment change |
P02 — Machine Usage Information
| Parameter | Description |
|---|---|
| P02.01 | Current machine operation mode |
| P02.02 | Load / idle time ratio |
| P02.03 | Number of starts in the last 1 hour |
| P02.04 | Number of starts in the last 24 hours |
| P02.06 | Percentage of time on load in the last 1 hour |
| P02.07 | Percentage of time on load in the last 24 hours |
P03 — Alarm and Error Logs
Stores the last 50 alarm and fault records in chronological order. P03.01 is the most recent record. Each record contains the alarm or error code and description, the time and date it occurred, the machine status at the time of the fault, and stage pressures and motor current readings at the moment of the event. Use this log as the first reference when diagnosing recurring or intermittent faults.
P04 — Event Records
Stores the last 200 system events in chronological order, including starts, stops, mode changes, and operator interactions. Each record includes the event description, time, and date. Use P04 to review operational history and identify patterns preceding alarms.
P05 — OEM Information
Displays South-Tek Systems contact and address information as configured at the factory.
P06 — Controller Information
Displays AirMaster Q2 part code, serial number, software ID, software version, and configuration file. Provide these details to South-Tek Systems when requesting technical support for controller-related issues.
P07 — Machine Information
Displays unit-specific identification data including machine producer, model, serial number, nominal pressure, motor serial number, and production year. Provide the serial number from P07 in all communications with South-Tek Systems.
P08 — Alarm and Error Code Descriptions
Contains descriptions for all alarm and error codes (P08.01 through P08.252). Cross-reference any active alarm code from P00.01 or P03 with the corresponding P08 entry for a plain-language description of the fault. See the Alarms & Troubleshooting article for corrective actions.
Operating Modes
Manual Start / Stop
The compressor can be started and stopped at any time by pressing the Start (I) and Stop (O) buttons on the control panel. Manual mode is used during initial startup verification, maintenance checks, and any situation where automatic cycling is not desired.
Automatic Start / Stop
In automatic mode, the AirMaster Q2 reads HP receiver pressure via a pressure transmitter and compares it against the configured start and stop setpoints. When pressure drops to the start setpoint the compressor starts automatically. When pressure reaches the stop setpoint the compressor stops. The system will restart without operator intervention as demand requires. The standard pressure differential is 10% of working pressure — for example, a system set to 580 PSI will cycle between approximately 522 PSI and 580 PSI.
Auto Drain Operation
The system uses solenoid-controlled automatic drain valves on the LP receiver, HP receiver, and filter assemblies to purge condensate during operation. The drain solenoid is energized during normal compressor operation, holding the drain valves closed. Every 10 minutes, the solenoid de-energizes for approximately 5 seconds, allowing the drain valves to open and expel accumulated condensate. This cycle repeats continuously during operation.
If drain valves are not cycling, or are stuck open or closed, refer to the Alarms & Troubleshooting article for corrective steps. Manual condensate drain points are also provided beneath each water separator — open these briefly at least once per shift during initial operation to verify condensate is being removed.
Pressure Switch Adjustment
The pressure switch controls automatic start/stop cycling for systems not relying solely on the PLC transmitter. Adjustment is made using the Red Adjustment Screw on the pressure switch body while the compressor is running. Turning the screw clockwise increases the upper (stop) pressure setpoint; turning it counterclockwise decreases it. The standard differential between start and stop pressure is 10% of the working pressure setpoint.
Inlet Pressure Monitoring
The AirMaster Q2 continuously monitors inlet pressure via a dedicated pressure sensor and will generate obstructive condition codes if inlet pressure falls outside configured limits. These codes prevent the compressor from loading under conditions that could cause damage or reduced output.
| Code | Condition | How to Clear |
|---|---|---|
| R:2130 / L:2130 | Inlet pressure below minimum threshold (P15.15) | Inlet pressure must recover to P15.15 + P15.16 combined value |
| R:2131 / L:2131 | Inlet pressure above maximum threshold (P15.17) | Inlet pressure must drop to P15.17 minus P15.18 value |
| A:2131 | Inlet pressure alarm — reached P16.16 parameter value | Restore inlet pressure to within the 85–115 PSI operating range |
| E:2131 | Emergency stop — inlet pressure reached P17.81 parameter value | Restore inlet pressure, then press Reset — contact South-Tek if fault persists |
Oil Level Switch
A float-type oil level switch is located in the crankcase. If oil level drops below the minimum threshold, the float opens the control circuit and stops the motor automatically. The controller will display a low oil level signal. Do not reset and restart the compressor until the cause of oil loss has been identified and the crankcase has been refilled to the correct level. See the Filter & Preventive Maintenance article for the oil check and refill procedure.
Related Articles
- High-Performance Air Skid (HPA-75-ENC) — Overview & Specifications
- High-Performance Air Skid (HPA-75-ENC) — Installation & Startup
- High-Performance Air Skid (HPA-75-ENC) — Filter & Preventive Maintenance
- High-Performance Air Skid (HPA-75-ENC) — Alarms & Troubleshooting
- High-Performance Air Skid (HPA-75-ENC) — Safety Guidelines
- High-Performance Air Skid (HPA-75-ENC) — Parts List & Assembly Reference
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