Display Descriptions - Extech Instruments 48VTR User Manual

Display Descriptions

Process Variable (PV) Display
• During normal operation, the top LED (red digits) displays the actual process
measurement (temperature, voltage, or current input signal). This process measurement
is known as the "Process Variable" or PV.
• When the user accesses one of the four programming levels, the red LED digits show
the currently selected parameter.
• The red LED digits also display controller error messages. Controller programming and
error messages are explained later in this section.
Setpoint Variable (SV) Display
• During normal operation, the bottom LED (green) displays the user-programmable
Setpoint Variable (SV). This represents the target to which the controller's output will
adjust the process. To adjust the Setpoint, use the up/down arrow keys.
• Note that the Setpoint cannot be adjusted higher or lower than the high and low limit
parameters programmed in Menu Level 4.
• While programming the controller, this green LED display shows the current setting for
the currently selected parameter (shown on the red LED digits). For example if the red
LED is displaying input type (type), the green LED shows the current selection. The user
could then use the up/down arrow keys to scroll to, and select, the desired input type.
Display Status Indicators
'ALM' Status Indicator (Alarm Relay Status LED)
This red LED is lit when the Alarm relay is active. Also, this LED flashes when the Alarm
is configured as an Event/Soak timer and is in the process of counting down. Refer to
the dedicated section on Soak and Event Alarm Timers and also Appendix 'A' for more
on Alarm/Timer functions.
'OUT' Status Indicator (Control Output Status LED)
This green LED switches on when the control output is active.
AUTO TUNE Status Indicator
When the controller is Auto Tuning, the rightmost decimal point on the green LED
display will flash. When the meter is finished tuning, the decimal point will stop flashing.
Auto Tuning may take from several minutes to several hours depending upon the
process in question. Refer to the Auto Tuning section for more information.
PV Display Error Messages:
AdEr: A/D converter is inoperable. Unit must be repaired or replaced.
Flashing PV: Over range condition with regard to input signal.
OPEN: Input sensor not connected or is inoperable.
13 Model 48VTR - Version 5.0 – January 2006