Honeywell HA40 Fault / Alarm 1 / Alarm 2 / Alarm 3 Set-Up Menus, Configure Menu To Define Channel

2.2.3 Fault / Alarm 1 / Alarm 2 / Alarm 3 Set-Up Menus

Alarm 1, 2 and 3 have identical menus. The only difference between each is that A1 front panel LED indicators are yellow while A2 and A3 are red. Typical applications often have A1 set at a WARN level, A2 at a HIGH level and A3 at a higher SHUT DOWN level. However, it is important to understand there is no functional difference between A1, A2 and A3 (since their configuration menus are identical, only one is shown in Figure 2-19). The Fault menu is identical to A1, A2, A3 except Fault alarms are always low trips (alarm activates as input goes below the set point) and Fault alarms may not be set for latching operation.

Figure 2-3. Alarm/Fault Setup Menu

•Set Point is entered in engineering units and determines the value at which the alarm trips. For example, if a channel

monitors 0-50 ppm H2S and the desired alarm level is 10 ppm, the correct entry is 10.00. A one percent dead band prevents alarm chatter. This means after tripping an alarm the input must move at least 1% of full scale back through the setpoint for the alarm to auto reset.

•The ON Delay / OFF Delay entries allow ON and OFF time delays affecting how long the trip-point must be surpassed before an alarm event transition occurs. ON delays are limited to 10 seconds while OFF delays may be as long as 120 minutes. Delays are useful in many applications to prevent nuisance alarms and unwanted cycling into and out of alarm conditions.

•Low Trip is set for NO to increase alarms or YES to decrease alarms to determine if the alarm activates upon exceeding or falling below the set-point.

•Latching determines either manual or automatic alarm reset operation. YES requires a manual Alarm Reset to unlatch the alarm even though an alarm condition no longer exists. YES also causes this alarm’s common relay, front panel LED, and optional discrete relay to latch. NO allows all outputs for this alarm to automatically reset after the alarm condition clears.

Common alarm LED indicators on the left side of the front panel indicate the status of A1, A2 A3 alarms. The common Fault LED is on the lower right side of the front panel. Any new alarm event causes the associated LED to flash until an Alarm Reset occurs causing an acknowledged steady on condition. Operators should recognize new alarms by a flashing LED. Alarm Reset also acknowledges, or deactivates, audible devices driven by the AUDIBLE ALARM option connector J2 (see Figure 3.2)

2.2.4 Configure Menu To Define Channel

The next menu option, after the Alarm menu, is Configure. It allows setting Name and EUNIT 10 digit ASCII fields, defines the measurement range with ZERO & SPAN entries, number of Decimal Points of resolution the reading will have, and if the channel is Active.

Figure 2-4. Configure Menu to Define Channel