Measurements, Derived functions – GF Signet 8900 Multi-Parameter Controller User Manual
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Signet 8900 Multi-Parameter
11. Relay Mode Descriptions
The 8900 offers a wide selection of relay operating modes that enable the user to create complex control scenarios.
Internal relays (those installed on the two Relay modules) can be confi gured for all of the available modes.
External relays that are located in the 8059 External Relay module are limited to the basic relay modes as shown in the chart.
Maximum Proportional Pulse rate: 400 pulses per minute
Internal Relays
External Relays
Mode:
Off
Low
High
Window
USP
Advanced
Prop. Pulse
PWM
Vol. Pulse
Source:
Measurements
Flow
X
X
X
X
X
X
X
pH
X
X
X
X
X
X
ORP (Redox)
X
X
X
X
X
X
Conductivity
X
X
X
X
X
X
X
Pressure
X
X
X
X
Temperature
X
X
X
X
X
X
Level
X
X
X
X
X
X
Derived Functions
Sum
X
X
X
X
X
X
Difference
X
X
X
X
X
X
Ratio
X
X
X
X
X
X
% Reject
X
X
X
X
X
X
% Passage
X
X
X
X
X
X
% Recovery A
X
X
X
X
X
X
% Recovery B
X
X
X
X
% Recovery C
X
X
X
X
Power 2
X
X
X
X
Power 4
X
X
X
X
Multiple
X
X
X
X
X
Hysteresis
ime
Low Setpoint
Process
Hysteresis
ime
High Setpoint
Process
High Limit
Hysteresis
Hysteresis
Window
ime
Low Limit
Process
Low
•
Relay is activated when the process variable is less than the setpoint.
•
The relay is deactivated when the process variable becomes greater than the sum of
the setpoint and the hysteresis.
High
•
Relay is activated when process variable is greater than the setpoint.
•
The relay is deactivated when the process variable becomes less than the sum of
the setpoint and the hysteresis.
Window
•
In Window mode, a single relay is activated when the process variable moves above
or below a fi xed window of values.
•
The relay is deactivated when the process variable moves inside the window by
more than the hysteresis value.