Mitsubishi Electric 800 Series, Installation Manualline

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3 FAILSAFE OF THE SYSTEM WHICH USES THE
INVERTER
When a fault is detected by the protective function, the protective function activates and outputs the Fault signal. However,
the Fault signal may not be output at an inverter's fault occurrence when the detection circuit or output circuit fails, etc.
Although Mitsubishi assures the best quality products, provide an interlock which uses inverter status output signals to
prevent accidents such as damage to the machine when the inverter fails for some reason. Also at the same time consider
the system configuration where a failsafe from outside the inverter, without using the inverter, is enabled even if the
inverter fails.
Interlock method which uses the inverter status output signals
By combining the inverter output signals to provide an interlock as shown below, an inverter failure can be detected. (For
details of each signal, refer to the FR-E800 Instruction Manual (Function).)
*1
This interlock method cannot be used when a PM motor is used.
l
When using various signals, assign the functions to Pr.190 to Pr.196 (Output terminal function selection) referring to the
following table.
Checking by using the Fault signal output from the inverter... (a)
When the inverter's protective function is activated and the inverter output is stopped, the Fault (ALM) signal is output.
(The ALM signal is assigned to terminals A, B, and C in the initial setting). With this signal, check that the inverter operates
properly. In addition, negative logic can be set. (ON when the inverter is normal, OFF when the fault occurs.)
Checking the inverter operating status by using the Inverter operation ready signal output from the inverter ... (b)
The Inverter operation ready (RY) signal is output when the inverter power is ON and the inverter becomes operative.
Check if the RY signal is output after powering ON the inverter.
No. Interlock method Check method Used signals
a Inverter protective function operation Operation check of an alarm contact.
Circuit error detection by negative logic.
Fault (ALM) signal
b Inverter operating status Operation ready signal check. Inverter operation ready (RY) signal
c Inverter running status
Logic check of the start signal and running
signal.
Start (STF or STR) signal
Inverter running (RUN) signal
d
Inverter running status
*1
Logic check of the start signal and output
current.
Start (STF or STR) signal
Output current detection (Y12) signal
Output signal
Pr.190 to Pr.196 settings
Positive logic Negative logic
ALM 99 199
RY 11 111
RUN 0 100
Y12 12 112
CAUTION
l
Changing the terminal assignment using Pr.190 to Pr.196 (Output terminal function selection) may affect the other functions. Set
parameters after confirming the function of each terminal.
ALM
(when output
at NC contact)
RES
Out
p
ut
fr
eque
ncy
Inverter fault occurrence
(trip)
Reset ON
ON
Reset processing
(about 1 s)
OFF
Time
ON OFF