Operation Modes - PENN Controls - VFD68Bxx - VFD68Cxx - VFD68Dxx - Three‐Phase Motor Speed Controller - VFD68 Three‐Phase Variable Frequency Drive

VFD68 Variable Frequency Drives Technical Bulletin

PENN Controls
Product name
VFD68 Three‐Phase Variable Frequency Drive
Document type
Technical Bulletin
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The VFD68 drive’s mode of operation is indicated by the mode of operation LEDs (labeled PU, EXT, and NET) on the drive’s operation panel (Figure 1).

PU Mode: The Parameter Units (PU) mode is manual control mode. In PU mode, the drive and motor are completely controlled using the buttons and the setting dial on the drive’s user interface. No external analog signals or network signals control the drive operation. The PU mode is typically used to set up, test, and troubleshoot the drive and motor operation using controlled input signal values.

EXT Mode: In the External (EXT) mode, the drive and motor respond to a signal or signals from one or two (external) analog input signal devices, such as pressure transducers or analog controllers. This is the typical mode of operation for the drive when it controls a condenser fan or other three-phase HVACR motor application.

PU/EXT Mode: In PU/EXT mode, the drive responds to the connected external signal devices and the drive setup values can be edited. The PU/EXT mode is typically used to set up your drive for initial operation, or to adjust setup parameters on an operating application.

NET Mode: In Network (NET) mode, the drive connects to and communicates over a network bus with other network devices and receives operating (Read/Write) commands from a master device on the network. The Network mode is not currently supported on VFD68 drives.

The VFD68 drives are RS485, RTU-compliant ModBus® subordinate devices. For more information, see

MON Mode: Shows motor speed represented as frequency (Hz) or RPM.