Dwyer Instruments Digihelic DHC Series - Page 6

MAIN MENUS AND SUBMENUS
Main Menu Selections (Upper Right Display Reads MENU)
• Pin - Set a custom pin code to lock out access to all menu settings
• oPEr Operation - Selection of pressure, velocity or ow mode, display units and
output scaling
• SP Set Point - Enable/disable set points
• AL Alarm - Enable/disable alarm limits, other alarm settings
• rLy Relay - Congure relay source and action when active
• inP Input - Congure external input
• diS Display - Monitor and adjust display related settings: Peak, valley, % output
and dampening
• Conn Connection - Congure RS-485 serial parameters and protocol
• CAL Calibration - Perform user zero and span, restore factory default settings, view
device serial number
Pin - SUB MENU
In order to prevent unauthorized modication of settings, a pin number can be
congured. Pin entry is enabled when the congured pin number is anything other
than 0000.
oPEr (Operation) MAIN MENU
The oPEr MENU contains SUB MENUs that select the operating mode, display unit,
and analog output scaling of the instrument.
The SUB MENUS are:
• ≡odE - Mode
• Unit - Display Unit
• POL - Pressure Output Low
• POH - Pressure Output High
• KFAC - Velocity K-Factor
• VOL - Velocity Output Low
• VOH - Velocity Output High
• AREA - Duct Area
• FOL - Flow Output Low
• FOH - Flow Output High
• uoUt - Voltage Output Range
If the instrument mode is set to Pressure, the oPEr MENU will include the POL and
POH SUB MENUs. If the instrument mode is set to Velocity, the oPEr MENU will
include the KFAC, VOL and VOH SUB MENUs. If the instrument mode is set to Flow,
the oPEr MENU will include KFAC, AREA, FOL and FOH SUB MENUs. These menus
will be discussed under their respective sections following the Unit (Velocity) SUB
MENU and Unit (Flow) SUB MENUs sections.
≡odE (Mode) SUB MENU
Set the mode of operation of the instrument.
• PRES - Pressure
• VEL - Velocity
• FLOW - Flow
Unit(Pressure) SUB MENU
For pressure mode, the following units are available:
• INWC - Inches of water column
• FTWC - Feet of water column
• MMWC - Millimeters of water column
• CMWC - Centimeters of water column
• PSI - Pounds per square inch
• INHG - Inches of mercury
• MMHG - Millimeters of mercury
• MBAR - Millibar
• PA - Pascal
• KPA - Kilopascals
• HPA - Hectopascals
• OZIN - Ounce inches
Unit (Velocity) SUB MENU
For velocity measurement, the following units are available:
• SFPM - Standard feet per minute
• M/S - Meters per second
Unit (Flow) SUB MENU
For ow measurements the following units are available:
• SCFM - Standard cubic feet per minute
• M
3
/H - Cubic meters per hour
The Available Flow Ranges table below shows the ow ranges available with the
maximum duct size and K-Factor selected for each input range.
POL and POH SUB MENUs
Pressure output low and pressure output high are used to scale the current and voltage
output. Set POL to the desired display reading for 4 mA output. Set POH to the desired
display reading for 20 mA output. POL can be greater than POH. In this situation, the
analog outputs are reverse acting.
KFAC SUB MENU
The K-Factor sub menu becomes accessible if the instrument mode is set to Velocity or
Flow. When the DHC is used with a Pitot tube, the manufacturer may specify a K-Factor.
The adjustment range is 0.001 to 9.999. The factory setting is 1.
VOL and VOH SUB MENUs
Velocity output low and velocity output high are used to scale the current and voltage
output. Set VOL to the desired display reading for 4 mA output. Set VOH to the desired
display reading for 20 mA output. VOL can be greater than VOH. In this situation, the
analog outputs are reverse acting.
AREA SUB MENU
The Area sub menu becomes accessible if the instrument mode is set to Flow. The duct
area is specied in either ft
2
or m
2
depending on the ow unit selected. The adjustment
range is 0.13-25.0 ft
2
(0.012-2.323 m
2
). The factory setting is 1 ft
2
(0.093 m
2
).
FOL and FOH SUB MENUs
Flow output low and ow output high are used to scale the current and voltage output.
Set FOL to the desired display reading for 4 mA output. Set FOH to the desired display
reading for 20 mA output. FOL can be greater than FOH. In this situation, the analog
outputs are reverse acting.
Air velocity and ow readings are based upon standard dry air
conditions with an ambient temperature of 70°F and a barometric
pressure of 29.92 INHG. Maximum velocity range is obtained with K-Factor set to
maximum value (9.999).
NOTICE
AVAILABLE VELOCITY RANGES
Input Range in w.c. SCFM Range M/S Range
±0.25
±0.5
±1.0
±2.5
±5.0
±10.0
±25.0
±50.0
±100.0
±20.02 x1K
±28.31 x1K
±40.04 x1K
±63.31 x1K
±89.53 x1K
±126.6 x1K
±200.2 x1K
±283.1 x1K
±400.4 x1K
±101.7
±143.8
±203.4
±321.6
±454.8
±643.2
±1017
±1438
±2034
AVAILABLE FLOW RANGES
Input Range in w.c. SCFM Range M
3
/H Range
±0.25
±0.5
±1.0
±2.5
±5.0
±10.0
±25.0
±50.0
±100.0
±500.5 x1K
±707.8 x1K
±1.001 x1M
±1.583 x1M
±2.238 x1M
±3.165 x1M
±4.005 x1M
±7.078 x1M
±10.01 x1M
±850.4 x1K
±1.203 x1M
±1.701 x1M
±2.689 x1M
±3.893 x1M
±5.378 x1M
±8.504 x1M
±12.03 x1M
±17.01 x1M
PRESSURE RANGE VS. AVAILABLE UNITS
INWC FTWC MMWC CMWC PSI INHG MMHG MBAR PA KPA HPA OZIN
.1000
.2500
.5000
1.000
2.500
5.000
10.00
25.00
50.00
100.0
.2083
.4167
.8333
2.083
4.167
8.333
2.540
6.350
12.70
25.40
63.50
127.0
254.0
635.0
1270
2540
.2540
.6350
1.270
2.540
6.350
12.70
25.40
63.50
127.0
254.0
.1806
.3613
.9032
1.806
3.613
.1839
.3678
.7356
1.839
3.678
7.356
.1868
.4671
.9342
1.868
4.671
9.342
18.68
46.71
93.42
186.8
.2491
.6227
1.245
2.491
6.227
12.45
24.91
62.27
124.5
249.1
24.91
62.27
124.5
249.1
622.7
1245
2491
6227
.1245
.2491
.6227
1.245
2.491
6.227
12.45
24.91
.2491
.6227
1.245
2.491
6.227
12.45
24.91
62.27
124.5
249.1
.1445
.2890
.5780
1.445
2.890
5.780
14.45
28.90
57.80
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