Hitachi SJ300 Series 사용자 설명서

SJ300 Inverter

Appendix B

The communication test mode verifies that the inverter can properly send and receive data via 
the RS485 serial port. Follow the steps below to perform the communication test.

1. Remove the serial cable (if present) connected to the TM2 connector block of the control 

terminals, as shown below.

NOTE: It is not necessary to connect a loopback jumper. The RS485 port uses a transceiver for 
communications, which already allows simultaneous transmitting and receiving.

2. Use the front panel keypad to navigate to parameter C071, Communication Speed

Selection. Change parameter C071=02 and press Store. Value 02 is the Test option. Now the 
inverter is ready to conduct the loopback test.

3. Turn the inverter power OFF and then ON again. Observe the keypad display and compare 

to the results shown below.

4. Press the Stop/Rest button on the keypad to return the inverter keypad/ display to normal 

operation.

5. Change C071 to its original setting (default is C071=04). Otherwise, while C071=02, the 

inverter will perform the communications loopback test at each powerup.

SP SN RP SN

Serial

communications

TM2

PASS

FAIL