Emerson Rosemount 56, Инструкция по эксплуатации

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Section 9: Alarm Relay Functions Instruction Manual
April 2017 LIQ-MAN-56
68 Alarm Relay Functions
9.2.2 Setup
Access high/low concentration (setpoint) alarms by pressing ENTER/MENU from the main
screen and then Program/Relays/Configure Relay. From the main relay programming screen,
program this feature as follows:
1.
Relay: Assign a relay by highlighting the desired relay 1-4 and press ENTER/MENU.
2. Type: Select Setpoint as the relay type and press ENTER/MENU.
3. Assign: Assign S1 (sensor 1), S2 (sensor 2 if available) or other available parameters to
the designated relay and press ENTER/MENU.
4. Logic: Set High for a high setpoint or Low for a low setpoint and press ENTER/MENU.
5. Setpoint: Enter the desired setpoints value. Press ENTER/MENU.
6. Deadband: To set deadband as a measurement value, enter the change in the process
value needed after the relay deactivates to return to normal (and thereby preventing re-
peated alarm activation). Press ENTER/MENU.
7. Select NEXT. Press ENTER/MENU to advance to the next setup screen.
8. Normal state: Set the normal alarm condition as Open or Closed and press
ENTER/MENU. Program the normal state to define the desired alarm default state to nor-
mally open or normally closed upon power up.
* See Appendix 1 – HART and Device Variables
9.3 Delay Timer
9.3.1 Description
Delay Timer is a concentration control scheme which delays live measurement after chemical
addition using (one or all four of) of the 56 alarm relays. This ensures sufficient mixing time
in a vessel or recirculation loop before live sensor measurement, preventing unmixed
readings that might cause overshooting. Relay On time and Delay times are field-
programmable. Typical applications that would utilize the Delay Timer are: concentration
control in vessels, pH adjustments for neutralization and endpoint control for oxidation-
reduction reactions.
Relay Function Limits and Selections Default
Setpoint NA NA
Logic Low/High High
Setpoint * *
Deadband * 0.000
On time 0 to 999.9 min 0 min
Delay time 0 to 999.9 min 0 min
Normal state Close/Open Open
Table 9-2. Defaults and programmable limits