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Okuma OSP Controller
Servo/Axis · Intermediate
Okuma OSP Alarm A 1139 - MCS DD encoder (slave sensor) initialization failure
The DD encoder (slave sensor) on the named axis or spindle failed its power-up initialization sequence over the encoder link. The code identifies which initialization step failed, the type of communication or parameter error, and supporting data; a special code ($FFFF) indicates abnormal voltage detected at the encoder fuse. This alarm occurs only on ICB-H controls.
1139
Okuma OSP Alarm A 1139 - MCS DD encoder (slave sensor) initialization failure
MCS DD encoder (slave sensor) initialization failure
The DD encoder (slave sensor) on the named axis or spindle failed its power-up initialization sequence over the encoder link. The code identifies which initialization step failed, the type of communication or parameter error, and supporting data; a special code ($FFFF) indicates abnormal voltage detected at the encoder fuse. This alarm occurs only on ICB-H controls.
Common Causes
- Defective DD encoder (slave sensor)
- Damaged or loose encoder link cable or connector
- Incompatible or corrupted encoder parameters (multi-turn range, data format, protocol version)
- Abnormal encoder fuse voltage (outside 10.6-13.8 V)
- Faulty inverter unit control board
Troubleshooting Steps
- 1Read the code number shown with the alarm: code XX = Encoder link initialization step at error detection (0 reset through 7 AT mode start); code YY=0 = Communication error; ZZZZ shows encoder link error status C2ERR; code YY=1,2,3 = Transmission start/finish or reception finish time over; ZZZZ shows transmitted frame info QC2MTINF; code YY=4 = Abnormal response address; ZZZZ shows the responding device's network address; code YY=5 = Abnormal response code; ZZZZ shows alarm code plus positional data status (see alarm 1136); code YY=6 = Parameter error; ZZZZ identifies the parameter fault (1-6); code XXYY=$FFFF = Abnormal voltage at encoder fuse; ZZZZ is the measured voltage (normal 10.6-13.8 V)
- 2Read the XXYYZZZZ code: XX is the initialization step where it stopped (0 reset, 1 network address setting, 2 basic communication info request, 3 communication software version change, 4 device info acquisition, 5 parameter change, 6 position detection start, 7 AT mode start); YY is the error type (0 communication error, 1-3 transmission/reception time over, 4 abnormal response address, 5 abnormal response code, 6 parameter error).
- 3If XXYY = $FFFF, the encoder fuse voltage is abnormal: ZZZZ is the measured voltage (12 V = $9980; normal 10.6-13.8 V, allowable $8800-$B000). Check the encoder power supply and fuse before anything else.
- 4Power down and lock out the control; inspect the encoder link cables and connectors at the DD encoder and the inverter unit for looseness, pin damage or contamination, then reseat.
- 5If YY = 6, ZZZZ gives the parameter fault: 1 too few parameters received, 2 incompatible basic communication info, 3 multi-turn detection range over, 4 incompatible protocol version, 5 incompatible positional data format, 6 incompatible abbreviated data mode - have the encoder parameters verified against the machine data.
- 6If YY = 5, use the alarm code and positional data status in ZZZZ together with alarm 1136 (MCS DD Encoder error) to narrow the fault.
- 7If cables and parameters check out, the DD encoder itself or the inverter unit control board is suspect; contact Okuma service with the full XXYYZZZZ code.
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