Emerson unidrive sp User Manual

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SM-Uni Enc Pl
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254 Unidrive SP Advanced User Guide
www.controltechniques.com Issue Number: 10
Wire-break detection
It may be important to detect a break in the connections between the drive and the position feedback device. This feature is provided for most
encoder types either directly or indirectly as listed below.
Pr x.50 Encoders Fault description
2
Ab, Fd, Fr, Ab.SErvo,
Fd.SErvo, Fr.SErvo,
SC.SErvo
Hardware detectors on the A(F), B(D,R) and Z signal detect a wire break.
2
SC, SC.HiPEr,
SC.EndAt,
SC.SSI
SC.SErvo
The differential levels of the sine and cosine waveforms are available to the drive, from this the drive detects wire
break if Sine
2
+Cosine
2
are less than the value produced by two valid waveforms with a differential peak to peak
magnitude of 0.25V (1/4 of the nominal level).
This detects wire break in the sine and cosine connections.
4, 5
SC.HiPEr, SC.EndAt,
EndAt
Wire break in the comms link is detected by a CRC or timeout error.
5, 6 SSI
Wire break detection is difficult with these devices. However, if power supply monitoring is enabled the drive will be
looking for a one at the start of the message and a zero to indicate that the power supply is okay. If the clock stops
or the data line is disconnected the data input to the drive may stay in one state or the other and cause a trip.

Emerson unidrive sp Specifications

General

Brand	Emerson
Model	unidrive sp
Category	Controller
Language	English