GE Hydran 201i, Instruction Manual

Page: 210 / 300

Chapter 11 • Operating the Hydran 201
i
System
11-2 Rev. 6, March 2011 Part 17997
Note: With this method, the analog outputs and the alarm contacts are not connected to a
SCADA system.
11.1.1.1 Method Drawbacks
The periodic, visual monitoring method has a deficient response time following the
detection of an alarm; this response time cannot be inferior to the period of time between
two inspections. The Hydran 201
i System, however, has a response time measured in
minutes.
11.1.2 Alarm Monitoring
The alarm monitoring method solves the disadvantages of the periodic, visual monitoring
method as follows:
• Connecting the alarm contacts to an alarm panel (or any other SCADA system) located
in the station’s control room.
• Continuous alarm monitoring.
• Periodic, visual reading (weekly) of the gas level on the display of the Hydran 201T
i ’s
or the Hydran 201C i -1. For details on the various methods of data reading, see
Section 11.2 on page 11-5.
• Manual logging of the gas level readings.
For details on the alarms and relays operation, see Chapter 10.
11.1.2.1 Method Drawbacks
The alarm monitoring method solves the response time inadequacy of the periodic, visual
monitoring method (Section 11.1.1 on page 11-1), but does not provide any information to
anticipate and prevent alarms.
Moreover, no information is available to immediately evaluate the severity of this alarm.
For example, a rapid gas level increase and a daily trend increase trigger the same alarm.
These two alarm conditions, however, do not have the same importance.