Resolver open circuit (SD2) due to troubled 24 V supply (eliminated from V02.03)

Behaviour of the new version?
The behaviour of the 8400TopLine is more robust when it comes to a troubled 24 V supply or interference levels in the resolver cable.

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Which products are affected?
TopLine with firmware version < 02.02

What happens?
The Sd2 monitoring (resolver monitoring) is accidentally triggered

When does the problem occur?
If speed/position feedback via a resolver at X7 is selected: Since the resolver feedback uses analog signals based on pulse width modulation, these signals are of course subject to fluctuations/deviations from the normal level. If the signals are outside certain tolerance limits, the 8400 TopLine triggers an Sd2 resolver error.
Compared to other Lenze controllers (9300, ECS, 9400) the 8400 TopLine has rather close tolerance limits. Hence applications with resolver feedback which can be operated with controllers of the series 9300, ECS and 9400 in a trouble-free manner are now a lot more sensitive. According to present knowledge drives with Pancake resolvers with a transfer ratio of 0.3 are particularly affected by this problem if the resolvers are not mounted with total accuracy.
Additionally interference pulses may cause the monitoring to respond e.g. due to the switching of an electromechanical 24 V brake that uses the same supply voltage, and/or a poor shield connection of the resolver cable/motor cable shield.

Diagnostics options?
The controller reports an Sd2 resolver error although the resolver feedback system operates trouble-free.The drive runs without noticeable problems when the Sd2 monitoring is switched off.

Short-term measures/recommendations?

Short-term measures/recommendations
Ensure that the EMC mounting instructions defined for the 84 TL will be consequently observed.
If this does not lead to an improvement:
Reconfigure the resolver monitoring to warning and proceed as described in the attachment.

Final solution
Adapting the resolver feedback system (hardware) synchronously with the next SW release.

Evaluation:
Due to rather close tolerance limits, the monitoring of the 8400 TopLine is more sensitive than the monitoring of servo controllers of the series 9300, ECS and 9400. Especially applications that are changed over from these series to 8400 TopLine indicate this behaviour as an error because trouble-free operation was possible with the previous device. Take one of the measures described to ensure trouble-free operation.

Information taken from Service Message No. 23/2012.