ABB ProKiln GAC400 Operating Instruction page 76

76 ProKiln GAC400 PROBE GAS SAMPLING SYSTEM | OI/GAC400-EN REV. A
... 10 Diagnosis / error messages
... HMI error displays
Example 2: Maintenance Request menu
This example shows the Maintenance Request menu. In this
example there is an indication of a Yellow Maintenance Request
at the top right corner of the HMI, plus a green OK indication
showing that the system is still operating. It can also be seen
that the Alarm originates from a -101S2 safety switch as
indicated with a yellow marker. See the complete maintenance
request list below for further examples.
In general, the following approach is used:
H: high limit alarm
HH: too high limit alarm (high-high)
L: low limit alarm
LL: too low limit alarm (low-low)