Error Diagnostics Using The Leds - Mitsubishi Electric MELSEC ST Series Installation Manual

Trouble Shooting

Error Diagnostics using the LEDs

5.3
In chapter 3 there are additional instructions for ST module LEDs
Head station
b If the "RUN" LED of the head station is not lit up check whether
– the correct station number has been set on the head station switches.
– the LEDs "SYS" and "AUX" of all power distribution modules are illuminated.
– a power distribution module is installed to the right of the head station.
– the correct base module is used for the power distribution modules to the right of the
head module. Pay attention to the modes "H" and "R"!
– the capacity of the power supply is sufficient.
b If the "BF" LED of the head module is illuminated, check whether
– the station number set on the switches is identical with the station number that is used
in the slave parameters.
– the set parameters correspond to the actual system set-up.
– the master station works without problem.
– the wiring of the PROFIBUS/DP network is error-free and terminating resistors are
present.
b If the "ERR" LED of the head module is lit up, then an error code can be read out.
I/O modules
b If the "RUN" LED of an I/O module is not illuminated, then check whether the LEDs "RUN",
"SYS" and "AUX", of the power distribution modules are illuminated.
b If only the "RUN" LED of an ST module flashes slowly, then replace the electronics module
or base module.
b If the "RUN" LEDs of multiple ST modules, arranged directly next to each other, flash
slowly, then replace the base module that is installed to the left of the malfunctioning mod-
ules. If afterwards the "RUN" LEDs continue to blink, then replace at the first malfunctioning
module (to the left of the malfunctioning module) first the electronics modules and then the
base module.
b If the "ERR" LED of an I/O module is illuminated, then replace this module.
b If the "ERR" LED flashes for the ST1Y2-TE2 and ST1Y16-TE2 output modules, then
excess voltage or the excess temperature monitoring has tripped. Resolve the cause (for
example a short circuit).
Power distribution modules and power feeding modules.
b If the "ERR" LED of an I/O module is illuminated, then replace this module.
b If the "ERR" LED flashes, and if the "SYS" LED is switched off at the same time, then the
feed for the "SYS" voltage is too low.
b If the "ERR" LED flashes, and if the "AUX" LED is switched off at the same time, then the
feed for the "AUX" voltage is too low.
42 MITSUBISHI ELECTRIC