Allen-Bradley 857-RAA, User Manual

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Rockwell Automation Publication 857-UM002C-EN-P - February 2018 29
Configure the Base 857 Relay Chapter 4
Troubleshooting If an RTD sensor is disconnected (open circuited) a value of -200 ºC is
returned for the respective sensor channel. As well, a status indicator called
‘Ext. Al disconnected’ will be enabled within the Output Matrix of the base
857 relay.
If an RTD sensor is short circuited, a value of -250 ºC is returned for the
respective sensor channel. A status indicator called ‘Ext. Al short circuit’ will be
enabled within the Output Matrix of the base 857 relay.
If power is lost to the 857-RAA or if communications between the base relay
and the 857-RAA are lost:
• Each sensor channel displays a value of -250 ºC.
• There are two status indicators within the Output Matrix to provide
feedback on the communication link status to the RTD scanner.
‘REMOTE Comm.’ which is activated when the communication link to
the 857-RAA is active or ‘REMOTE Comm Inactive’.
• Timeout counter increases in the Protocol menu
(1)
If power is lost to the 857-RAD or if communications between the base relay
and the 857-RAD is lost, when using Modbus RTU-protocol then:
• Each sensor channel value freezes
• AI error counter increases in the External analog inputs menu
• There are two status indicators within the Output Matrix to provide
feedback on the communication link status to the RTD scanner.
‘EXTENSION Comm.’ which is activated when the communication
link to the 857-RAD is active or ‘EXTENSION Comm Inactive’
• Timeout counter increases in the Protocol menu
(1)
XFault Fault reactance ohms [Ω]
SagMin Minimum voltage sag Pu value of voltage [pu]
Sagmax Maximum voltage sag Pu value of voltage [pu]
U0 zero sequence voltage Percentage of zero sequence setting [%]
AL1 Analog Input #1 Scalable reading of AI1 (from 0…20mA) [mA]
AL2 Analog Input #2 Scalable reading of AI2 (from 0…20mA) [mA]
AL3 Analog Input #3 Scalable reading of AI3 (from 0…20mA) [mA]
AL4 Analog Input #4 Scalable reading of AI4 (from 0…20mA) [mA]
Io1 Ground fault current channel 1 Ground Fault current #1 [A]
Io2 Ground fault current channel 2 Ground Fault current #2 [A]
Iocalc Phasor sum IL1 + IL2 + IL3 Phasor sum IL1 + IL2 + IL3 [A]
Table 11 - Measurands that can be Assigned to Analog Outputs
(1) If the application uses Remote or Extension-communication port, an alarm can be generated using relay logic, for example,
inverted Remote.comm – signal can be used to drive an LED indicator on the front of the relay.