ABB 800XA 5.1 Trends
We have ABB 800 XA 5.1 system with redundant aspect & connectivity server installed in our GPP4 power plant unit at SCL Ras site. Recently, we faced an issue regarding spurious spikes in most of the trend parameters of all our three nos. of controllers of ABB servers.
These spikes were analysed and found that it lasted for more than 48 hours and every spike occurred at an interval of exactly 1minute for all parameters.
System events and logs along with snapshots of trends are attached for your reference and needful. Kindly suggest for corrective action to avoid repetition of such event of false spikes.
Configuration details are as below.
Product Name: 800XA 5.1 SYSTEM FP4
1. Product version : 5.1
2. 800xa base system with redundant aspect & connectivity server.
”it is Monday and all trends are OK”, then time is accidentally put forward (+2days) to Wednesday. Immediately when this takes place the Max Time setting forces all logs to extrapolate last known value from Monday to Wednesday (=flat line in trend).
A few minutes later time is corrected back to Monday. But damage is already done to the logs...
Basic History trends will afterwards seemingly have two (2) values from Monday until Wednesday:
1) The true (raw) value recorded from ”correct” time
2) The false (extrapolated) values ”flat line” recorded when time was set forward
There is nothing to clean this ”backwards” in time, but with an applog operation in Basic History you can clean ”forward” in time. However, you need to detect, react and do this quickly (i.e. already on ”Monday”).
Long term solution: configure a correct and stable clock synchronization:
a) Exclude unreliable time sources
b) Disable possibility for operators to set time in computers and controllers