2.5 Frequency Converter Inputs and Outputs
The adjustable frequency drive operates by receiving control input signals. The adjustable fre-
quency drive can also output status data or control auxiliary devices. Control input is connected
to the adjustable frequency drive in three possible ways. One way for adjustable frequency drive
control is through the LCP on the front of the adjustable frequency drive when operating in local
(hand) mode. These inputs include start, stop, reset, and speed reference.
Another control source is through serial communication from a serial bus. A serial communication
protocol supplies commands and references to the adjustable frequency drive, can program the
adjustable frequency drive, and reads status data from the adjustable frequency drive. The serial
bus connects to the adjustable frequency drive through the RS 485 serial port or through a com-
munication option card.
The third way is through signal wiring connected to the adjustable frequency drive control termi-
nals (see figure below). The adjustable frequency drive control terminals are located below the
adjustable frequency drive LCP. Improperly connected control wiring can be the cause of a motor
not operating or the adjustable frequency drive not responding to a remote input.
Terminal Descriptions
1.
Digital I/O terminals
2.
RS 485 (EIA-485) terminal
3.
Analog I/O terminals
4.
USB connector
Figure 2.1: Control Terminals
2 Operator Interface and Adjustable Frequen-
cy Drive Control
High Power Service Manual for VLT
®
FC Series
Adjustable Frequency Drives
2-14
MG.90.L1.22 - VLT
®
is a registered Danfoss trademark
2
Summary of Contents for VLT HVAC FC 100
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