The HPCF Series nitrogen generator is controlled through a proprietary PLC with a 3.5" full-color touchscreen. This article describes every screen and control function available to operators and technicians. Controls for supporting equipment — air compressor, refrigerant dryer — are not covered here; refer to those manufacturers' documentation.
Powering On and Off
The HPCF generator is powered on and off using an external power switch or disconnect, typically supplied and installed by others as part of the electrical installation. Refer to the site's electrical drawings for the location of the main disconnect. Powering off at the disconnect immediately stops all generator functions and should only be used as an emergency measure during normal operation — use the Start/Stop button on the touchscreen for routine shutdowns.
Home Screen
The Home Screen is the primary operating display. It is visible immediately when the PLC powers on and shows the following information:
| Display Element | Description |
|---|---|
| Start/Stop button (upper left) | Green = system running; Red = system stopped. Press to toggle between states. |
| System status | Displays current operating state: Running, Standby, or Stopped |
| Purity setpoint | Factory-configured nitrogen purity target for the unit |
| Nitrogen storage tank pressure | Live pressure reading from the nitrogen storage tank transducer |
| Nitrogen tank purity | Live O2 purity reading (displayed if O2 sensor option is included) |
| Run hours (upper right) | Cumulative hours the system has been actively cycling and producing nitrogen |
| Navigation buttons | Menu, Graph, and Alarms (Alarms button appears only when an active alarm is present) |
Starting and Stopping
Starting the Generator
Press the Start/Stop button in the upper left corner of the Home Screen. The button will illuminate green to confirm the system has started. The generator will begin cycling through the PSA adsorption beds and producing nitrogen to fill the storage tank.
Standby Mode
When the nitrogen storage tank pressure reaches the cut-out pressure, the system automatically enters Standby mode. Nitrogen production pauses and the Home Screen will indicate the Standby state. No action is required — when storage tank pressure falls back to the cut-in pressure, the generator automatically restarts and resumes production.
Stopping the Generator
Press the Start/Stop button to stop the generator. The button will illuminate red to confirm the system is stopped. When stopped, all internal process valves return to their normal (de-energized) positions. The air compressor does not need to be manually valved off — the internal valve system automatically stops airflow to the generator.
System Run Hours
The run hour counter is displayed in the upper right corner of the Home Screen, below the current time and date. Run hours are counted only when the system is actively cycling and producing nitrogen. Time spent in Standby mode is not included. Run hours are used to track maintenance intervals — refer to the Filter & Preventive Maintenance article for service schedules.
Trending Graphs
Press the Graph button on the Home Screen to access historical sensor trend data. All units include a nitrogen storage pressure transducer, so tank pressure trending is available on every unit. Additional optional graph channels include:
- Oxygen (O2) purity
- Incoming air flow
- Nitrogen outlet flow
- Incoming air pressure
Contact South-Tek Systems if additional graphical displays are needed.
| Button | Function |
|---|---|
| Y-Axis min/max fields | Tap the field to open a numeric keypad; enter desired min/max pressure range; graph rescales automatically |
| M | Scroll through historical graph data |
| G | Toggle horizontal gridlines on/off |
| Next | Navigate to the next available graph channel |
| Exit | Return to the Home Screen |
Main Menu
Press the Menu button on the Home Screen to access the Main Menu. The Main Menu is password protected. Enter user password 6557 when prompted to gain access. The Factory Settings option requires a separate factory-level password — contact South-Tek Systems support if factory access is needed.
The Main Menu provides access to the following screens:
| Menu Option | Purpose |
|---|---|
| Sensor Setup / Calibration | View and calibrate installed sensors |
| Alarms / Filter Parameters | Configure alarm setpoints, view alarm history, check filter status |
| Cut-In / Cut-Out Parameters | View nitrogen storage tank pressure setpoints (factory set) |
| Maintenance Menu | Manually toggle individual valves and components for diagnostic purposes |
| Communication Settings | Configure Ethernet / MODBUS TCP/IP and remote access settings |
| Language | Switch PLC display language between English and Spanish |
| Factory Settings | South-Tek factory access only — not accessible with the user password |
Sensor Setup / Calibration
All sensors use a 2-point linear calibration. The calibration screen allows the user to enter a low-point and high-point reference value at opposite ends of the sensor's operating range. Standard sensors on every unit include:
- Nitrogen storage tank pressure transducer
- O2 sensor (standard on current HPCF units)
Optional additional sensors may include: incoming air temperature, incoming air pressure, incoming air flow, incoming air pressure dewpoint, nitrogen outlet pressure dewpoint, and nitrogen outlet flow.
Alarms / Filter Parameters
Alarm Setpoints
The Alarms / Filter Parameters screen displays and configures the following user-adjustable alarm setpoints:
| Alarm | Trigger Condition |
|---|---|
| O2 High Level | Triggered when the O2 purity reading exceeds the configured setpoint (indicates purity has dropped below spec) |
| Low N2 Tank Pressure | Triggered when nitrogen storage tank pressure falls below the configured setpoint |
Each alarm can be individually enabled or disabled using the On/Off toggle on the Alarm Setup screen. For alarm descriptions, causes, and corrective actions, refer to the Alarms & Troubleshooting article.
Alarm Status and History
Press the red Alarm button (bottom right of the screen) to open the Alarm Status screen, which shows current alarm states and provides access to:
| Screen | Information Available |
|---|---|
| Alarm Details | List of alarms with the date and time each was triggered |
| Alarm History | Scrollable log of up to 256 historical alarms, including trigger time, duration, and deactivation time |
| Clear History | Clears the alarm history log; requires entry of 1111 to confirm |
| Filter Info | Displays current filter status as Good or Overdue; press the corresponding filter button after a change to reset the filter timer |
| FRP Freq | Displays the factory-recommended filter element replacement schedule and current status (OK / Overdue) for each element; reset via the reset button |
Pressure Cut-In / Cut-Out Parameters
The nitrogen storage tank pressure transducer feeds the PLC with a continuous pressure reading. The PLC uses two setpoints to manage production automatically:
| Setpoint | Behavior |
|---|---|
| Cut-Out pressure | When storage tank reaches this pressure, the generator enters Standby and stops producing nitrogen |
| Cut-In pressure | When storage tank falls to this pressure, the generator automatically restarts and resumes production |
To view the current factory setpoints: press Menu → Cut-In / Cut-Out Parameters.
Maintenance Menu
The Maintenance Menu allows individual valves and components to be toggled manually, independent of the automatic control sequence. This is used by South-Tek technicians and trained personnel for diagnostic and troubleshooting purposes.
Communication Settings
The Communication Settings screen configures Ethernet connectivity for remote monitoring and MODBUS TCP/IP communication. To connect:
- Assign a static IP address for the PLC and enter it in the IP Address field.
- The Subnet Mask and Gateway fields are not required for intranet access only.
- Press Connect to PC. A Connected status confirms the PLC is discoverable on the network.
For remote access via the Unitronics remote monitoring application, a static IP address is also required. This software allows a technician to interact with the PLC remotely as if standing in front of the screen. Search "Remote Access" on the South-Tek Systems support portal for setup instructions.
Data Logging (Optional)
Units equipped with the data logging option can record sensor values to a micro SD card for trend analysis and record-keeping.
- From the Graph screen, press Graph Options → Data Log to open the data logging screen.
- The screen displays current, average, maximum, and minimum values for all installed sensors.
- Press Press to Start Data Analysis to begin logging. The log point counter (upper right) will increment. Press again to pause; press Reset Stats to clear logged values.
- To log to SD card: format the card using the Unitronics SD Card Suite software (search "SD Card" on the support portal for installation instructions). Insert the formatted SD card; confirm SD Card: OK status.
- Press Press to Log to SD Card to begin recording. The File # will increment and the Log Count will reset to 0.
- To stop logging, press Press to Stop SD Logging. Before removing the card, press Eject SD and wait for the Ready signal before physically removing the card.
Related Articles
- HPCF Series — Overview & Specifications
- HPCF Series — Site & Utility Requirements
- HPCF Series — Installation & Startup
- HPCF Series — Alarms & Troubleshooting
- HPCF Series — Filter & Preventive Maintenance
- HPCF Series — Safety Guidelines
- HPCF-SFI — Overview & Specifications
Contact South-Tek Systems
Phone: (910) 415-1880
Email / Ticket: support@southteksystems911.zendesk.com