Dwyer 8B - Manual (Page 9)

Page 9
CONTROL OPERATION DESCRIPTION
The HOME display is the normal display while the control is operating. If no errors or
functions are active, the HOME display will indicate the Process Variable (the temperature,
pressure, flow, %RH, etc.) that is being measured on the top display and the Set Variable on
the bottom display.
Items that can change the HOME display are the Ramp and Soak function and any error
messages. Descriptions of these special displays follow.
If the Ramp and Soak feature is active, then bottom display will show the current execution
pattern and current execution step. The UP and DOWN arrows can be pressed to change
the bottom display to show the Set Point (SP) of the current execution step or the Time
Remaining (r-ti) of the current execution step. After changing the bottom display to either the
Time Remaining or the Set Point, the ENTER key must be pressed to display the values.
Error Messages are shown on page 26.
OPTIONS
Event Input
When the controller is ordered with the Event Input Option (See page 3 for ordering
information), two event inputs are available. The event input is triggered by contact closure
between event 1 (EV1) or event (EV2) contact terminal and signal ground (SG) contact
terminal.
Event 1 controls the output operation of the control. When the event 1 contact terminals are
open, the output is active. When the event 1 contact terminals are closed, the output is de-
activated. The outputs can also be controlled via the Run/Stop parameter using the front
keypad or by using the RS-485 communications.
Event 2 allows the user to switch between two temperature set points. Each temperature set
point has independent control parameters.
Current Transformer Alarm Function
The current transformer option allows the user to have an alarm contact trigger due to a loss
of current or a surge in current to the control output. When using the current transformer
input, the desired alarm contact should be set to alarm type 13 in the Initial Setting Menu
(Page 21). The current transformer should be wired according to the appropriate wiring
diagram on page 6 and page 7. The high and low alarm set points can be set from 0.5 to 30
Amps. The display resolution is 0.1 Amps and the accuracy is ±0.5 Amps with the included
current transformer.