6. Troubleshooting 
 
 
 
6 - 19 
 
Alarm No. 
34 
Communication or CRC error between NC and drive unit 
An error was detected in the data received from the NC. 
 Investigation details  Investigation results  Remedies  SV SP
The state is improved.  Replace the cause of the fault. 1  Try replacing the terminator or battery 
unit. 
The state is not improved.  Investigate item 2. 
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The connection is incorrect.  Replace the cable. 2  Check the NC bus communication 
cable connection. 
• Is the cable disconnected? 
• Is the communication pair cable 
connected in reverse? 
There is no problem.  Investigate item 3. 
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The alarm is on the cable 
connections. 
Replace the cable. 3  Change the order of the connected 
drive units. 
(The rotary switch does not need to 
be changed.) 
The alarm is on the unit connections. Investigate item 4. 
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No abnormality is found in particular. Replace the unit. 4  Check if there is any abnormality in 
the unit's ambient environment. 
(Ex. Ambient temperature, noise, 
grounding) 
An abnormality was found in the 
ambient environment. 
Take remedies according to the 
causes of the abnormality. 
Ex. High temperature: 
    Check the cooling fan. 
 Incomplete grounding: 
 Additionally ground. 
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Alarm No. 
35 
NC command error 
The movement command data received from the NC was excessive. 
 Investigation details  Investigation results  Remedies  SV SP
The rapid traverse rate is large.  Check the rapid traverse rate limit. 1  Is the rapid traverse rate large for 
using a sub-micron system or rotary 
axis? 
The rate is not especially large.  Look for problems on the NC side, 
such as not being able to follow up 
the position FB. 
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Alarm No. 
36 
Communication or transmission error between NC and drive unit 
Communication from the NC was cut off. 
 Investigation details  Investigation results  Remedies  SV SP
The connector is disconnected (or 
loose). 
Connect correctly. 1  Check whether the NC bus 
communication cable connectors 
(CN1A, CN1B) are disconnected. 
The state is not improved.  Investigate item 2. 
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The connection is incorrect.  Replace the cable. 2  Check the NC bus communication 
cable connection. 
• Is the cable disconnected? 
• Is the communication pair cable 
connected in reverse? 
There is no problem.  Investigate item 3. 
{ {
The alarm is on the cable 
connections. 
Replace the cable. 3  Change the order of the connected 
drive units. 
(The rotary switch does not need to 
be changed.) 
The alarm is on the unit connections. Investigate item 4. 
{ {
No abnormality is found in particular. Replace the unit. 4  Check if there is any abnormality in 
the unit's ambient environment. 
(Ex. Ambient temperature, noise, 
grounding) 
An abnormality was found in the 
ambient environment. 
Take remedies according to the 
causes of the abnormality. 
Ex. High temperature: 
    Check the cooling fan. 
 Incomplete grounding: 
 Additionally ground. 
{ {