Hitachi MICRO-EHV+ Applications Manual page 168

Appendix
3. Trace [only for EHV-CODESYS V3.5 SP3 Patch 6]
If RUN/STOP switch is toggled from RUN to STOP while trace monitoring, following error message appears although
it is no problem practically. Click OK and choose "Download Trace" to restart. This message appears only when the
Stop switch definition is configured as Reset warm.
4. Cable disconnection
Do not disconnect communication cable while program file or config.cfg file is being downloaded. Otherwise it could
fail to establish online communication. In this case, cycle power and login again.
5. Power cycling
If MICRO-EHV+ without backup capacitor charged (more than 12 hours of power failure) is powered up and cycled
power just a few seconds after powered up, the PLC could fail to start the system program correctly (OK LED is not
lighting up). Login and execute "Reset origin" to reset the PLC.
6. Error code 20
Error code 20 is not supported in MICRO-EHV+ CPU ROM VER. 3.5.3.44 or older.
7. Modbus-TCP/RTU slave
If unsupported function code is sent from a master to MICRO-EHV+ as a slave, MICRO-EHV+ does not respond any
data although an exception response must be sent back according to Modbus protocol.
8. Modbus register address 0xFFFF
[EHV-CODESYS V3.5 SP3 Patch 6] When Modbus-RTU master is used, available register address must be from
0x0000 up to 0xFFFF however, register address 0xFFFF is not allowed to enter.
[HX-CODESYS V3.5 SP8 Patch 4] If register address 0xFFFF is used, Modbus master device does not work correctly.
Do not use address 0xFFFF.
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