Siemens LMV 5 Series, Technical Instructions, Page: 211 / 374

LMV Series Technical Instructions
Document No. LV5 ‐ 1000
SCC Inc. Page 3 Section 7
CANbus Faults Including “ AZL not on Bus ” and “ System Test ” (continued)
The most common CANbus errors are:

“AZL not on Bus”

Stuck in “System Test”

Error code 99

Error code A7, diagnostic 17
However, there are many additional error codes that can also be caused by an issue with the
CANbus network. The following procedure can be used to diagnose any CANbus related error:
1. Take the cover off of the last actuator (or PLL52 O
2
module) on the CANbus network wired
to terminal X51 on the LMV5. This should have only one 5 ‐ pin green connector plugged into
it. The other CANbus terminals should be empty, and is a perfect place to measure voltage.
Ensure that the following voltages are present on the pins of the empty CANbus terminal:

12 VAC between pins 12VAC1 and GND

12 VAC between pins 12VAC2 and GND

24 VAC between pins 12VAC1 and 12VAC2
When measuring to ground (GND), it is ok to have anywhere from 10.2 ‐ 13.2 VAC as long as
both measurements are the same. For example, it is okay to have 11 VAC between pins
12VAC1 and GND as long as there is also 11 VAC between pins 12VAC2 and GND. In
addition, the voltage between pins 12VAC1 and 12VAC2 must be exactly double the other
two measurements. If these three voltage measurements are correct, skip to step 3.
2. If one or more of the voltage measurements is incorrect, check the following:

CANbus fuses FU2 and FU3 are located on the right hand side of the LMV5. Check
that these fuses are not blown. If either one is blown, check the LMV5 wiring for
incorrect terminations. Once any wiring errors have been fixed, replace the blown
fuse.

The most common wiring error has to do with pins 3 and 4 on transformer terminal
SEK2. Pin 3 on terminal SEK2 should be wired to terminal X52, pin 4 on the LMV5.
Pin 4 on terminal SEK2 should be wired to terminal X52, pin 3 on the LMV5.

Make sure pin 3 on terminal SEK2 of the transformer is grounded properly.

Make sure the rest of the CANbus network is wired properly. See Section 2 for
additional wiring assistance.
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