HISTORY PRINTOUT
Pressing the PRINT key and then the HISTORY key allows the operator to obtain a printout of information relating to the last 6 Safety Shutdowns which occurred. The information is stored at the instant of the fault, re- gardless of whether the fault caused a lockout to occur. The information is also not affected by power failures (long term internal memory battery
When the HISTORY key is pressed, a printout is trans- mitted of all system operating conditions which were stored at the “instant the fault occurred” for each of the 6 Safety Shutdowns buffers. The printout will begin with the most recent fault which occurred. The most recent fault will always be stored as Safety Shutdown No. 1. Identically formatted fault information will then be printed for the remaining safety shutdowns.
Information contained in the Safety Shutdown buffers is very important when attempting to troubleshoot a sys- tem problem. This data reflects the system conditions at the instant the fault occurred and often reveals other system conditions which actually caused the safety threshold to be exceeded.
The history printout is similar to the operational data printout shown in the previous section. The differences are in the header and the schedule information. The daily schedule is not printed in a history print.
One example history buffer printout is shown below. The data part of the printout will be exactly the same as the operational data print so it is not repeated here. The difference is that the Daily Schedule is not printed in the history print and the header will be as shown below.
FORM
YORK INTERNATIONAL CORPORATION
MILLENNIUM LIQUID CHILLER
SAFETY SHUTDOWN NUMBER 1
SHUTDOWN @ 3:56PM 29 JAN 99
SYS | 1 | HIGH DSCH PRESS SHUTDOWN |
SYS | 2 | NO FAULTS |
HISTORY DISPLAYS |
|
The HISTORY key gives the user access to many unit |
|
and system operating parameters at the time of a unit |
|
or system safety shutdown. When the HISTORY key | 2 |
is pressed the following message is displayed. | |
|
D I S P L A Y S A F E T Y S H U T-
D O W N N O . 1 ( 1 T O 6 )
While this message is displayed, the UP or DOWN ar- row keys can be used to select any of the six history buffers. Buffer number 1 is the most recent, and buffer number 6 is the oldest safety shutdown that was saved.
After selecting the shutdown number, pressing the EN- TER key displays the following message which shows when the shutdown occurred.
S H U T D O W N O C C U R R E D
1 1 : 2 3 P M 2 9 M A Y 9 8
YORK INTERNATIONAL | 71 |
