Dwyer Instruments Digihelic DHC Series - Page 8

Conn (Connection) MAIN MENU
The Conn menu contains SUB MENUS to congure the RS-485 serial parameters and
selected protocol. The SUB MENUS are:
• Prot - Protocol
• ADDR - Protocol Address
• bAUd - Serial Baud Rate
• PAr - Serial Parity
• StP - Serial Stop Bits
Prot (Protocol) SUB MENU
• MOD - Modbus
®
Communication (factory setting)
• BAC - BACnet Communication
• NONE - Communication disabled
ADDR (Protocol Address) SUB MENU
This value sets the RS-485 device address. See the table below for protocol specic
ranges. The factory setting is 127. SUB MENU not available if protocol is NONE.
bAUd (Serial Baud Rate) SUB MENU
• 96 - 9600 bps
• 192 - 19200 bps
• 384 - 38400 bps
• 576 - 57600 bps
• 768 - 76800 bps
• 1152 - 115200 bps
• AUTO - Auto-baud (factory setting)
If the selected protocol is Modbus
®
communication, the AUTO setting will also
determine the serial parity and serial stopbits. If selected communication protocol is
BACnet, serial parity and serial stop bits are xed to NONE and 1 respectively. SUB
MENU not available if protocol is NONE.
PAr (Serial Parity) SUB MENU
• EVEN - Even Parity (factory setting)
• ODD - Odd Parity
• NONE - No Parity
SUB MENU not available if protocol is NONE or BAC or if serial baud rate is AUTO.
StP (Serial Stop Bits) SUB MENU
• 1 - One stop bit
• 2 - Two stop bits
SUB MENU not available if protocol is NONE or BAC or if serial baud rate is AUTO.
CAL (Calibration) Main Menu
The CAL menu contains SUB MENUS to perform eld calibration, reset settings, and
display information. The SUB MENUS are:
• ZERO - Zero Calibration
• SPAN - Span Calibration
• rSt - Reset Factory Defaults
• Sn 1 - Display Serial Number part 1
• Sn 2 - Display Serial Number part 2
ZERO (Zero Calibration) SUB MENU
For accurate calibration, do not apply any pressure when performing this function.
Press and hold the ENTER button unit the process value is cleared. The display will
show a dash in each digit starting with the left most position. After 4 dashes have been
displayed, the process value will be displayed and the new zero will be applied. For
best results, perform the zeroing function in the same orientation you will mount the
DHC.
SPAN (Span Calibration) SUB MENU
For an accurate calibration, perform a Zero calibration rst. The pressure to apply
will depend on the selected mode and the POH, VOH or FOH value. Apply a stable
pressure equal to the congured output high value. Press and hold the ENTER button
until the process value is cleared. The display will show a dash in each digit starting
with the left most position. After 4 dashes have been displayed, the process value will
be displayed and the new span will be applied. If the span cannot be applied, a FAiL
message will be displayed. This error could occur if the applied pressure is too low or
too high.
rSt (Reset Factory Defaults) SUB MENU
• NO - Do nothing
• YES - Reset all settings, clear user calibration
After selecting YES the instrument will reboot itself.
Sn 1, Sn 2 (Serial Number Display) SUB MENUS
The serial number of the instrument can be viewed on the display using these menus.
The rst 4 characters are available with Sn 1 and the second 4 characters are available
with Sn 2.
SPAL (Set Point/Alarm) MENU
The SPAL menu contains the set point trigger and reset value as well as the alarm
limits. This menu is accessible from the home screen with the SPAL button. If both set
points and both alarm limits are disabled, then the SPAL menu will contain no SUB
MENUS and pressing the SPAL button will not do anything. The SUB MENUS are:
• SP1T - Set Point 1 Trigger
• SP1R - Set Point 1 Reset
• SP2T - Set Point 2 Trigger
• SP2R - Set Point 2 Reset
• ALLO - Alarm Low Limit
• ALHI - Alarm High Limit
SP1T, SP2T (Set Point Trigger) SUB MENUS
These SUB MENUS set the trigger value for each set point. When the process value
equals the set point trigger value, the set point is considered active. These SUB
MENUS are only present if their corresponding enable setting is set to ON.
SP1R, SP2R (Set Point Reset) SUB MENUS
These SUB MENUS set the reset value for each set point. When the process value
equals the set point reset value, the set point is considered inactive. These SUB
MENUS are only present if their corresponding enable setting is set to ON.
ALLO (Alarm Low Limit) SUB MENU
This SUB MENU sets the alarm low limit value. If the process value is less than the
alarm low limit value, the low alarm is considered active.
ALHI (Alarm High Limit) SUB MENU
This SUB MENU sets the alarm high limit value. If the process value is greater than the
alarm high limit value, the high alarm is considered active.
The range of the alarm limits depends on the selected mode. If both low and high
alarm limits are enabled, they cannot be closer than 2% of full-scale to each other. The
dead bands of the alarm limits are xed at 1% of full-scale.
Protocol Range
Modbus
®
BACnet
1-247
0-127
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