Dwyer 16A - Manual (Page 11)

Page 11
THE HOME DISPLAY
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 tem-
perature, pressure, flow, RH, etc., that is being measured) on the top display and the
Set Variable (Set Point 1) on the bottom.
Items that can change the HOME display are the Auto/Manual function, the
Run/Hold function, the
Pro9 function, the Pct0 function, and any error message.
Description of these special displays follows.
If the Auto/Manual key is pressed, the Manual indicator lights, and the home
display is changed. The upper display continues to show the Process Variable (PV),
but the lower display changes to show the percentage of output in tenths of a per-
cent to 99.9% (0.0 to 99.9) or 100 if 100%. The display digit to the right of the num-
ber shows a flashing letter o to indicate that the value displayed is no longer the SV,
but percent output. The
SP2 percent output is indicated by the use of an overline on
the o . Access to the SP2 value is made by the INDEX key. See Auto/ Manual
Operation on Page 14 for further information.
If Pro9 is turned 0n , the HOME display changes the SV display from SP1 to the
Present Set Variable as calculated by the Ramp/Soak Programmer function. See
Programming and Operation for Ramp/Soak Feature below for more information.
If Pct0 (Secondary Menu) is turned 0n , the lower display changes to show the active
percentage of output as required to maintain SP1 . The display is similar to the
Auto/Manual display above, except that the percent indicators ( o , o ) do not flash, and
the output is displayed in whole percentages of output, not in tenths of a percent. If
the control has both
SP1 and SP2 , the lower display will alternate between the SP1
percent output and the SP2 percent output.
Error messages are listed on Pages 37-39.
PROGRAMMING AND OPERATION FOR RAMP / SOAK
FEATURE (16A3 ONLY)
The Ramp / Soak feature offers a great deal of flexibility by allowing changes in the
set point to be made over a predetermined period of time. Dwell times can be pro-
grammed, and the alarm output relay can be programmed to open or close during
any of the segments.
Theory of Operation
The 16A3 Series controls offer a very simple approach to programming a ramp.
Rather than requiring the operation to calculate an approach rate (usually in degrees
per minute), the 16A3 does the calculation internally. Thus, the operator only needs
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