Siemens 6RA70 specifications Start-up faults, F050

Fault

No.

Description
Cause as a function of fault value	Further information (r047.002 to r047.016)
(r047.001, r949.001 or r949.009 with acknowledged error)

F048

Fault in measuring channel for digital speed sensing using pulse encoder (active in all operating states)

1. Disturbances on encoder cables:

Faults on the encoder cables (transitions to 0 with a 1 signal or to 1 with a 0 signal) are signalled as a rotational direction change by the evaluation circuit. Frequent changes in rotational direction can occur only at speeds around 0.

The fault message is activated if 10 consecutive pulse encoder signal evaluations identify “direction of rotation change” at a speed of ≥ 48 rev/min and an EMF > threshold (see below).

2. Pulse encoder defective:

The fault message is activated if, at an EMF > threshold (see below) 10 consecutive pulse encoder signal evaluations identify “implausible characteristics” of these signals (i.e. frequent rotational direction changes, edges too close together, failure of an encoder cable or short circuit between two encoder cables).

Possible fault causes

♦EMC-related interference on a pulse encoder signal (terminals 28 to 31)

♦Pulse encoder defective

♦Interruption in an encoder cable

♦Short circuit between an encoder cable and the supply voltage or another encoder cable

♦P110 or P111 is incorrectly set (resulting in incorrectly calculation of EMF)

Note:

When the speed encoder is operating correctly, signal sequences, which are characteristic of a faulty pulse encoder or disturbances on the pulse encoder cables, may occur continuously at the input terminals (e.g. continuous changes in rotational direction or short pulse intervals) at about 0 speed, e.g. as the result of slight oscillation around a bright/dark transition on the speed encoder disk).

For this reason, fault F048 is not activated until the EMF > 10% of P078.001∗	3 ∗ 2 .
	π

Fault value:

1Disturbances on encoder cables

2Defective pulse encoder

9.1.2.8Start-up faults

F050

Optimization run not possible (active in all operating states)

A fault has occurred during an optimization run.

NOTE

The contents of r047, Index 002 to 016, can provide specialists with more detailed information about fault causes. For this reason, please read out and document all the indices associated with this fault and pass them on when you contact Siemens for help.

Fault value:

1Armature current is too low when α=30° and EMF=0.

(average armature current <75% of IA, motor or <75% of IA, rated) Possible cause:

•Armature circuit interrupted

•High-resistance load

•P150 (Alpha G limit) has been set to excessively high value

2It was not possible to determine the armature circuit resistance (P110) because the armature current was ≥ 37.5 % of P100 in fewer than 20 of the 150 firing cycles of the measuring phase.

Possible cause:

•Armature current of 37.5% of P100 (I A, motor) is no longer possible (although a current of 75% of P100 was already flowing, maybe a fuse has blown).

9-14	Siemens Energy & Automation
	SIMOREG DC Master Base Drive Panel Operating Instructions