MODULE #4 - PROGRAM DIGITAL FILTER AND REMOTE INPUT
PROGRAM DIGITAL FILTERING
If the displayed process signal is difficult to read due to small process
variations or noise, increased levels of filtering will help to stabilize the
display. This programming step may be used in conjunction with display
rounding programming (PRO1&2)tohelp minimize this effect. The digital
filter used is an “adaptive” filter. That is, the filter coefficients change
dynamically according to the nature of the input signal. This feature
simultaneously allows the filter to settle quickly for large input changes while
providing a stable display reading for normal process variations. Because of
the adaptive nature of the filter, it cannot be characterized in terms of a time
constant. The following table lists the maximum settling time for a step input
to within 99% of the final value.
Filter Value Settling Time (99%)
“FILtEr” < > “0” - no digital filtering 1.5 sec.
“1” - normal filtering 2 sec.
“2” - increased filtering 6 sec.
“3” - maximum filtering 13 sec.
PROGRAM FUNCTION OF E1-CON AND OPTIONAL E2-CON
PIN
The function of the remote input “E1-CON” pin (TBA #4) and, if the
totalizer option is installed, the remote input “E2-CON” pin (TBC #1) are the
same. Functions are activated, as described in the appropriate function, when
connected to signal common (TBA #5). Whether a function is edge or level
activated it must be held low for a minimum of 20 msec in order for the
function to occur. The remote input pins can be used simultaneously and with
any combination of functions. When pins are tied together and activated,
E1-CON function is generally performed first.
“E1-CON”< > “0” - If the Integrator/Totalizer/Peak/Valley/Display Offset
option is installed, a negative going edge offsets the displayed
temperature to zero. (At this time the E-Pin is activated, the value of the
actual temperature being displayed is placed in the location of the display
offset value. To bring the unit back into the normal temperature display
mode, reset the offset value to zero via the front panel.)
“1” - If the Integrator/Totalizer option is installed, a negative going edge
resets the contents of the Integrator/Totalizer to zero.
Integration/Totalization commences regardless of the state of the input.
“2” - If the Integrator/Totalizer option is installed, a negative going edge
resets the contents of the Integrator/Totalizer to zero and allows
Integration/Totalization as long as input is low. If the input goes high,
Integration/Totalization is stopped and the contents are saved. This acts
as a Integration/Totalization enable control from time T1 to T2.
“3” - A low level allows Integration/Totalization as long as the input is low.
If the input goes high, totalization is stopped and the contents are saved.
This acts as a totalization enable control from time T1 to T2.
“4” - A low level holds the display (display hold). While this input is low,
the indicator continues to process the input signal and drive the alarms,
Integrator/Totalizer, etc. with the actual signal. The contents of the
Integrator/Totalizer are stored at the same time the input display is held.
Note: If display hold is activated, and input value is requested via serial,
the value on the display will be sent instead of the actual input value
at that time.
“5” - If the Integrator/Totalizer option is installed, a negative going edge
resets both peak and valley buffers.
Note: If P/V is called up, a change will not appear on the display until the
next time the P/V is called up.
“6” - If the Integrator/Totalizer option is installed, a negative going edge
resets only the peak buffer and the indicator enters a peak reading display
mode as long as the input is low. If the input goes high, peak detection and
indication are stopped and the last peak reading is retained.
“7” - If the Integrator/Totalizer option is installed, a negative going edge
resets only the valley buffer and the indicator enters a valley reading
display mode as long as the input is low. If the input goes high, valley
detection and indication are stopped and the last valley reading is retained.
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