2190

Common Causes

• Faulty independent position encoder
• Damaged encoder link cable or loose connector between the encoder and the inverter unit
• Communication problem during the initialization sequence (time-over, wrong response, or parameter error)
• Defective inverter unit control board

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code XX=0 = Failure during reset step of the encoder link sequence; code XX=1 = Failure during net address setting; code XX=2 = Failure while requesting basic communication information; code XX=3 = Failure during communication software version change; code XX=4 = Failure while acquiring device information; code XX=5 = Failure during parameter change; code XX=6 = Failure at AT mode start; code YY=0 = Communication error; ZZZZ is the encoder link error status at detection
2. 2Record the object and full code. XX shows which initialization step failed (0 reset, 1 net address setting, 2 basic communication info request, 3 communication software version change, 4 device info acquisition, 5 parameter change, 6 AT mode start).
3. 3Read YY for the failure type: 0 = communication error, 1/2/3 = transmission or reception time-over, 4 = wrong response address, 5 = wrong response code, 6 = parameter error (ZZZZ then gives the parameter-related detail: 1 too few parameters received, 2 incompatible basic communication info, 3 multi-turn detection range exceeded).
4. 4Lock out machine power, then inspect the encoder link cable and connectors to the independent encoder for loose seating, bent pins, oil ingress, or chafing; clean and reseat.
5. 5Power up and see whether initialization completes; a time-over (YY=1/2/3) or communication error (YY=0) that persists after cable checks points to the encoder itself.
6. 6If YY=6, the encoder rejected its setup data; this typically requires correcting the encoder configuration with Okuma support rather than hardware replacement.
7. 7If the encoder and cabling check out, the inverter unit control board is the remaining suspect; record the alarm number, code, and object and contact Okuma service.