11-2 869 MOTOR PROTECTION SYSTEM – COMMUNICATIONS GUIDE
READING FAULT REPORTS CHAPTER 11: MODBUS MEMORY MAP
Reading Fault Reports
Fault report data is available via the file retrieval mechanism in 869 relay. The filename is
FaultReport1_#####.txt and the ##### refers to the fault report record number.
The fault report number is a counter that indicates how many fault reports have ever
occurred. Only the last fifteen fault reports are available for retrieval; a request for a non-
existent fault report file yields a null file.
The current value fault report counter is available in “Number of Fault Reports” Modbus
register.
Accessing Data via the User Map
The 869 has a powerful feature, called the User Map, which allows a computer to read up
to 125 non-consecutive data registers (setpoints or actual values) by using one Modbus
packet. It is often necessary for a master computer to continuously poll various values in
each of the connected slave relays. If these values are scattered throughout the memory
map, reading them would require numerous transmissions and would burden the
communication link. The User Map can be programmed to join any memory map address
to one in the block of consecutive User Map locations, so that they can be accessed by
reading these consecutive locations.
The 869 contains a user-definable area in the Modbus memory map. This area allows re-
mapping of the addresses of any Actual Values registers. The User Definable area has two
sections.
1. A Register Index area (40524 to 40648) that contains 125 Actual Values register
addresses
2. A Register area (30524 to 30648) that contains the data at the addresses in the
Register Index
Register data that is separated in the rest of the memory map may be re-mapped to
adjacent register addresses in the user-definable registers area. This is accomplished by
writing to register addresses in the user-definable register index area. This allows for
improved throughput of data and can eliminate the need for multiple read command
sequences. The user-definable register index is stored as a setpoint and therefore it is
“remembered” even when the power is removed.
Default User Map
Common actual values have been defaulted for the user. Below are the default registers.
Table 11-1: Default User Map
User Map Address Description Modbus Address
User Map Address 1,2 LED Status 30712 30713
User Map Address 3,4 LED Status 30708 30709
User Map Address 5,6 Contact Input 1-32 30700 30701
User Map Address 7,8 Contact Output 1-32 30706 30707
User Map Address 9,10 Virtual Input Status 1-32 30714 30715
User Map Address 11, 12 Virtual Output Status 1-32 30718 30719
User Map Address 13,14 Remote Input 1-32 30728 30729
User Map Address 15,16 Remote Output 1-32 30736 30737
User Map Address 17,18 Ia 31270 31271
User Map Address 19,20 Ib 31272 31273
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