7
Relay Logic
Effect of Acknowledge Key
Direct
(Alarm)
Switches OFF the Alarm output
No effect
Switches OFF the Alarm output provided no Alarm condition is pending
Switches ON the Trip relay (brings out of tripping) provided no Alarm condition is
pending
Latched
No
Reverse
(Trip)
No
Yes
Yes
Direct
(Alarm)
Reverse
(Trip)
Table 3.2
PV ERROR INDICATION
In case the PV falls below the Minimum Range or rises above the Maximum Range specified for the selected ‘Input Type’ or in
case the input sensor is open / broken; the PV Readout flashes the error messages listed in Table 3.3 below. The Figure 3.2
illustrates an open sensor condition for channel-14, for example.
Message
PV Error Type
Over-range
(PV above Max. Range)
Under-range
(PV below Min. Range)
Open
(Sensor open / broken)
Table 3.3
Figure 3.2
ALARMS
Scane
Plus
Manual
User Manual
SCANEX PLUS
Detail Alarm View
Pressing the Alarm Ack/View key also provides complete Alarm status information for the channels under alarm condition. The
information available is for view only. The Unit Readout indicates the ‘Channel Number’ under Alarm and the corresponding
‘Alarm Number(s)’ are indicated on the PV Readout. The UP/DOWN keys can be used to scroll through all the channels under
Alarm.
The example Figure 3.1 below illustrates the following case :
Channel-2 and Channel-12 are currently under Alarm condition. The active Alarms for Channel-2 are Alarm-1 and Alarm-4
while for Channel-12 it is only Alarm1.
MAIN
Display
Mode
Figure 3.1
Press UP / DOWN key
to view next / previous channel
in alarm condition
MAIN
Display
Mode
Press ALARM
ACK/VIEW key
Press PAGE or ENTER
key to return to
Main Display Mode
Alarm View
Mode
Alarm View
Mode