Emerson SI-Universal User Manual page 110

Encoder trips
The following table shows trips that can be initiated that are related to the position feedback
interface.
Drive trip
* Comms Timeout P2
* CRC Error P2
* SSI Error P2
Comms Timeout P2
Encoder Type P2
** Setup Changed P2
+ These trips can be enabled or disabled with P2 Error Detection Level (2x.040) bit 2.
* These trips can be enabled or disabled with P2 Error Detection Level (2x.040) bit 3.
** This trip can be enabled or disabled with P2 Error Detection Level (2x.040) bit 4.
*** BiSS is not currently supported.
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 position feedback devices either directly or
indirectly as shown in Table 7-9 on page 110.
Table 7-9 Wire-Break Detection
Device
There is no wire break detection of the A2, B2, and Z2 signals
AB, FD, FR
on the P2 position interface.
Wire break in the comms link is detected by a CRC or timeout
EnDat, BiSS*
error.
Wire break detection in the comms is difficult with these
devices. However, if power supply alarm bit monitoring is
enabled the drive will be looking for a one at the start of the
SSI
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.
* BiSS is not currently supported.
110
Encoders
EnDat, BISS***
EnDat, BISS***
SSI
EnDat, BiSS***
SSI
EnDat, SSI, BiSS***
BiSS***
All
Detection method
Reason for error
Comms timeout
Checksum/CRC error
Not ready at start of position transfer (i.e. data
input not one)
The encoder has indicated an error
+ Power supply alarm bit active
P2 Device type (2x.038),
P2 Comms Bits (2x.035), P2 Comms Baud Rate
(2x.037), P2 Calculation Time (2x.060),
P2 Recovery Time (2x.061), P2 Line Delay Time
(2x.062) and P2 User Comms Enable (2x.067)
are used to determine the time taken for the
communications exchange with the encoder. If this
time exceeds 250 μs a Comms Timeout P2 trip is
initiated.
The encoder could not be identified during auto-
configuration
A set-up parameter for the device has been
changed.
SI-Universal Encoder User Guide
Trip produced
None
Comms Timeout
SSI Power Trip
Issue: 2