Fault Positioning Actuator - Error Code 15; Internal Fault Actuator - Error Code 19 - Siemens LMV5 Series Technical Instructions

LMV Series
Fault Positioning Actuator – Error Code 15 (continued)
6. If everything else checks out okay, replace the actuator.
SQM45 and SQM48 actuators have dual potentiometers that provide feedback to the LMV5 to
verify actuator position. When these two potentiometers disagree, the LMV5 faults with an
error code 19. The diagnostic code will detail which actuator is having the problem. If an error
code 19 is encountered, check the following:
1. Ensure that parameter allowed Pot.diff is set to 15. This allows a maximum disagreement
of 1.5° between the two potentiometers.
2. If allowed Pot.diff is set to 15 and the LMV5 continues to receive error code 19, the
actuator must be replaced. The likely cause of the damaged actuator is excessive side load
on the actuator shaft or excessive vibration. Over time, excessive side load on the actuator
shaft can wear down the shaft bearings of the actuator. Since the potentiometers are
mounted directly onto the back of the shaft, they will disagree more and more as the shaft
bearings wear. Excessive vibration can also cause potentiometer wear and lead to an error
code 19.
3. It is imperative that proper couplings are used when mounting actuators. It is highly
recommended to use an SCC flexible coupling on all actuators. SCC couplings eliminate
excessive side load due to their design. Furthermore, SCC couplings allow up to 1/16" of
parallel misalignment and 3° of angular misalignment between the actuator and valve
shafts. See Document No. CPBK‐1000 for more information on available flexible couplings.
4. It is also important to use a rigid mounting bracket when mounting any actuator. Excessive
vibration over time can wear the potentiometer tracks. If the wear is too severe, error code
19 can result. Rigid mounting brackets help to minimize the effects of vibration. SCC offers
a wide variety of brackets and fully assembled valve actuator assemblies to ensure proper
mounting of actuators. See Section 1 for more details.
SCC Inc.
Internal Fault Actuator – Error Code 19
Page 7
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Technical Instructions
Document No. LV5‐1000
Section 7