Control Box 5.7 also known as "The Multi-Tasking Wonder" as it will let you operate 2 Pneumatic Seeders in parallel & independently of eachother however an additional adapter cable will be needed. The Control Box 5.7 is compatible with all sensor systems. 

Here are a few of the functions:

• Regulating & controlling the meter roll
• Electronic seed rate adjustment
• Discharge function
• Automatic calibration-test function
• Total hour counter and hours per day counter
• Total hectare counter and hectares per day counter
• Choice of different languages
• Calibration test & display in kg/ha and grains/m²
• Speed calibration
• Headland management (in combination with linkage sensor)
• Usage with different speed sensors (optional)
• Possibility for machine sensors (pressure monitor, fill level sensor) 2
• Manual override for preseeding application
• Option to include calibration button 2
• Option for regulating the electric fan
• Independent control of up to 2 meter rolls AND one electric fan
• One fill level sensor per meter roll possible

Control Box 5.2 can be used for 

PS 120

PS 200

PS 300

PS 500

PS 800