Duplex and Staging are optional features that link the PLCs of two nitrogen generators so they work together. They serve different goals: Duplex combines two units to meet a demand larger than one unit can supply, while Staging runs two units as an alternating, redundant pair so production continues if one unit goes down. Both keep run time balanced between the two units and coordinate preventive maintenance.
Figure 1: Two units linked in a Duplex or Staging configuration
Duplex (higher capacity)
Two generators normally run independently. Duplex integrates their PLCs so both units work together to meet a higher demand than a single unit can supply. It is typically used for large-scale applications, or where space limits favor two smaller units instead of one large one. The Duplex software keeps run time even between the two units and coordinates their preventive maintenance schedules.
Open it from Home → Menu → Pressure Settings → Duplex.
Figure 2: Pressure Settings (left) and Duplex Settings (right) screens
- Set Primary. On one of the two units, press "Press to Set Primary." This identifies that unit as the primary and the other as the secondary.
- Pressure Differential. A small pressure offset that keeps one unit from cycling more than the other, so the primary cycles after the secondary. Factory setting is 3 PSI.
- Switch-Over Hours Setpoint. The run time before the primary and secondary roles swap. Factory default is 1,000 hours; the user can adjust this on site.
- Current Run Hours. How long the unit has produced nitrogen in its present role, not counting standby time. When Current Run Hours reaches the Switch-Over Hours, the unit changes role (primary to secondary or vice versa) and Current Run Hours resets.
- Test. A commissioning aid that shortens the hour count to 5 seconds so you can verify the connections. For example, with Switch Hours set to 2, the units swap roles every 10 seconds (2 × 5 seconds) while running. Turning Test off resets the hour clock.
Staging (redundancy and failover)
Staging integrates two generators into an alternating, redundant system so nitrogen production continues if a single unit fails. It also balances wear by switching the primary unit after a set run time (1,000 hours by default), and it lets you perform scheduled preventive maintenance on one unit without downtime.
Open it from Home → Menu → Pressure Settings → Staging.
Figure 3: PSA Staging settings screen
- PSA Staging ON/OFF. Enables or disables staging.
- Current Run Hours. How long the unit has produced nitrogen, not counting standby time.
- Switch-Over Hours Setpoint. The run time before roles swap. Factory default is 1,000 hours; the user can change this on site. When Current Run Hours reaches the Switch-Over Hours, the running unit signals the other to start and the roles change.
Inter-unit wiring
Both Duplex and Staging require the two units' PLCs to be wired together. Two wires are pulled from one unit to the other (four wires total), and they can run together in the same conduit. The same wiring serves both features: Output 7 signals the opposing unit to assume primary, input I1 receives the staging signal, and input I2 receives the duplex signal.
- Connect Unit #1 TB-12B (main cabinet terminal blocks) to Unit #2 Relay A2.
- Connect Unit #1 Lower PLC Terminal Block 14 (Output 7) to Unit #2 Relay A1.
- Repeat the same wiring from Unit #2 back to Unit #1.
Figure 4: Duplex / Staging inter-unit wiring (same diagram applies to both)
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