Failsafe System Which Uses The Inverter - Mitsubishi Electric 800 Series Instruction Manual

3.7

Failsafe system which uses the inverter

When a fault is detected by the protective function, the protective function activates and outputs a fault signal. However, a fault
signal may not be output at an inverter's fault occurrence when the detection circuit or output circuit fails, etc. Although
Mitsubishi Electric 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.
No. Interlock method
a Inverter protective function
operation
b Inverter operating status
c Inverter running status
d Inverter running status
• When using various signals, assign the functions to Pr.190 to Pr.196 (Output terminal function selection) referring to
the following table.
Output signal Pr.190 to Pr.196 setting
Positive logic
ALM 99
RY 11
RUN 0
Y12 12
NOTE
• 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.
Check method
Operation check of an alarm contact.
Circuit error detection by negative
logic.
Operation ready signal check.
Logic check of the start signal and
running signal.
Logic check of the start signal and
output current.
Negative logic
199
111
100
112
Used signals
Fault (ALM) signal
Inverter operation ready (RY) signal
Start signal (STF signal, STR signal)
Inverter running (RUN) signal
Start signal (STF signal, STR signal)
Output current detection (Y12) signal
3. PRECAUTIONS FOR USE OF THE INVERTER
3.7 Failsafe system which uses the inverter
3
4
3
4
Refer to page
304
5
303
303, 550
6
307, 550
7
8
9
10
83