3 Internal Frequency Converter Operation
3.1 General
This chapter provides an operational overview of the main
assemblies and circuitry in the frequency converter.
3.2 Description of Operation
3.2.1 Control Logic Section
The control card includes most of the logic section (see
Illustration 3.2). The primary logic element of the control
card is a microprocessor, which supervises and controls all
functions of frequency converter operation. In addition, a
separate PROM contains the parameters to provide the
user with programmable options. These parameters are
programmed to enable the frequency converter to meet
specic application requirements. This data is stored in an
EEPROM providing security during power-down and also
allows the exibility to change the operational character-
istics of the frequency converter.
Illustration 3.1 Logic Section
Another part of the logic section is the removable LCP or
display mounted on the front of the frequency converter.
The LCP provides a user interface to the frequency
converter.
All programmable parameter settings can be uploaded into
the EEPROM of the LCP. This function helps in maintaining
a back-up frequency converter prole and parameter set.
Its download function can be used in programming other
frequency converters or restoring a program to a repaired
unit. The LCP is removable during operation to prevent
undesired program changes. With the addition of a remote
mounting kit, the LCP can be mounted in a remote
location.
Control terminals, with programmable functions, are
provided for input commands such as run, stop, forward,
reverse and speed reference. Additional output terminals
are provided to supply signals to run peripheral devices or
for monitoring and reporting status.
The control card logic
•
Communicates via serial link with outside devices
such as personal computers or Programmable
Logic Controllers (PLC).
•
Provides 2 voltage supplies for use from the
control terminals.
24 V DC is used for switching functions such as start, stop,
and forward/reverse. The 24 V DC supply also supplies 200
mA of power, which can partly be used to power external
encoders or other devices. A 10 V DC supply rated at 17
mA is also available for use with speed reference circuitry.
The analog and digital output signals are powered through
an internal supply. The 3 power supplies are isolated from
one another to eliminate ground loop conditions in the
control input circuitry.
2 relays for monitoring the status of the frequency
converter are located on the power card. These relays are
programmable through parameter group 5-4* Relays. The
relays are Form C. These relays have one normally open
contact, and one normally closed contact on a single
throw. The contacts of the relay are rated for a maximum
load of 240 V AC at 2 Amps resistance.
The logic circuitry on the control card allows for adding:
•
Option modules for synchronizing control
•
Serial communications
•
Additional relays
•
Cascade pump controller
•
Custom operating software
Internal Frequency Converte... TR150 and TR170 Service Manual
BAS-SVM04B-EN 02/2017 All rights reserved. 23
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