Input Signals; Output Signals - GE AF-650 GP Operating Instructions Manual

High Power Service Manual for Unit Sizes 6x

2.5.1 Input signals

The frequency converter can receive two types of remote input signals: digital or analog. Digital inputs are wired to terminals 18, 19, 20 (common), 27, 29, 32, and
33. Analog or digital inputs are wired to terminals 53 or 54 and 55 (common). The terminal functions are set by a switch found by removing the Keypad. Some
options may include additional terminals.
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Analog signals can be either voltage (0 to +10 VDC) or current (0 to 20 mA or 4 to 20 mA). Analog signals can be varied like dialling a rheostat up and down. The
frequency converter can be programmed to increase or decrease output in relation to the amount of current or voltage. For example, a sensor or external controller
may supply a variable current or voltage. The frequency converter output, in turn, regulates the speed of the motor connected to the frequency converter in
response to the analog signal.
Digital signals are a simple binary 0 or 1 which, in effect, act as a switch. Digital signals are controlled by a 0 to 24 VDC signal. A voltage signal lower than 5 VDC
is a logic 0. A voltage higher than 10 VDC is a logic 1. Zero is open, one is close. Digital inputs to the frequency converter are switched commands such as start,
stop, reverse, coast, reset, and so on. (Do not confuse these digital inputs with serial communication formats where digital bytes are grouped into communication
words and protocols.)
The RS-485 serial communication connector is wired to terminals (+) 68 and (-) 69. Terminal 61 is common and may be used for terminating screens only when
the control cable run between frequency converters, not between frequency converters and other devices. See Earthing Screened Cables in this section for correct
methods for terminating a screened control cable.

2.5.2 Output signals

The frequency converter also produces output signals that are carried through either the RS-485 serial bus or terminal 42. Output terminal 42 operates in the
same manner as the inputs. The terminal can be programmed for either a variable analog signal in mA or a digital signal (0 or 1) in 24 VDC. In addition, a pulse
reference can be provided on terminals 27 and 29. Output analog signals generally indicate the frequency converter frequency, current, torque and so on to an
external controller or system. Digital outputs can be control signals used to open or close a damper, for example, or send a start or stop command to auxiliary
equipment.
Additional terminals are Form C relay outputs on terminals 01, 02, and 03, and terminals 04, 05, and 06.
Terminals 12 and 13 provide 24 VDC low voltage power, often used to supply power to the digital input terminals (18-33). Those terminals must be supplied with
power from either terminal 12 or 13, or from a customer supplied external 24 VDC power source. Improperly connected control wiring is a common service issue
for a motor not operating or the frequency converter not responding to a remote input.
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