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8.3.2 Simple Communication
The AccUView LED can provide basic communications over simple
programs such as the Hilgraeve HyperTerminal that is included with
most Microsoft Windows packages. The user could also use Visual Basic
or other programs. The default communication parameters are 8 bits,
no parity and 1 stop bit. These parameters may be changed in the
extended
CONFIG
menu.
The master computer will send out:
• Byte #1 the attention character “:” in ASCII or
3A
Hex
• Byte #2 the address of the AccUView LED being queried
• Byte #3 and 4 CR LF or 0D 0A in hex
The AccUView LED will respond with:
• The same attention character “:” in ASCII or
3A
Hex
• The address of the AccUView LED
• The Reading
• The Unit (% T or ABS )
A sample communication would look like this:
(Master computer requesting a report from address #1)
: 1 CRLF
(AccUView LED set to address #1 Response)
:001 97.4 %T
8.3.3 Modbus Communication
Modbus communications is fully operational if the RS-485 option
(Catalog #19851A) is installed. The Modbus protocol communication
information is covered in a separate manual, Catalog #24570 and is
available as a free download from our website at www.hfscientific.com.
8.4 AccUView LED with Flow Alarm (Model 28042)
This model of the AccUView
LED has flow switch installed.
There is an additional menu in the
configuration which gives you the
selection of ON or OFF.
A “Low Flow” occurs under 1
Liter/minute and if the flow alarm
is enabled will cause a screen
indication. The flow alarm can
act on both the relays and the
4-20mA. Either relay, if set to Error
will change to an alarm state and
the 4-20 mA signal will change o
0, 2 or 4 mA (selected by ERLV)
unless it is set to OFF. A modbus
register is also set. This alarm
takes 2½ minutes of low flow to
actuate or restore. Please note
that the flow alarm is not sold as
an option and cannot be added.
9.0 Routine Maintenance
9.1 Cleaning the Flow Through Cuvette
Measurement cuvettes used for the flow through should be clean and free
of marks or scratches. Cleaning is accomplished by cleaning the interior and
exterior with a detergent solution and then rinsing several times with distilled
or de-ionized water. The cuvette can be replaced by first shutting off the flow
using the provided shutoff clamp; unscrewing the old cuvette and replacing
with a fresh clean one. Recalibration will be required for accurate operation.
9.2 Replacing or Installing the Desiccant
Pouch
The AccUView LED continuously checks the condition of the desiccant.
When the desiccant gets in such a condition that it may cause
problems, the instrument will display
DESC
on the lower portion of the
display to indicate the presence of humidity.
Proper use of the supplied desiccant is essential in maintaining
the performance of the instrument. The desiccant has been
designed to have a long life; however, replacement of the
desiccant pouch will be required from time to time.
It is essential that the enclosure seal on the instrument base be
maintained to ensure adequate desiccant life. Inspect the seal each
time the desiccant pouch is replaced. Replace or reseat the seal if it is
found to be defective.
The desiccant should be replaced when the instrument displays
DESC
.
A new sealed desiccant pouch and indicator card are available from HF
scientific part #21555R.To initially install or remove the old desiccant, simply
unscrew the four corner thumbscrews and remove the electronics half of the
instrument. Open the bag protecting the new desiccant pouch and replace
(or install) immediately. To speed up the recognition, by the instrument, of the
new desiccant it will be necessary to reset the instrument by disconnecting
the sensor interconnect cable for 2 seconds and then reconnecting it.
Ensure this cuvette is tightened to the flow through before each
operation. After a cuvette it is recommend that the water be run with
the flow through not installed to allow for inspection of the seal.
NOTICE
Humidity Indicator
(Humonitor Card)
Replaceable
Desiccant Pouch
(Part 21555R)
Drain Seal
Center of drain
opening in
older models
Once the bag is opened, install the desiccant pouch immediately
to prevent premature degradation of the desiccant.
NOTICE
9.3 Replacing the Source LED
The UV source lamp in the AccUView LED has a very long life, but is
dependent on the setting of the Duty Cycle and operating conditions.
See section 7.14 for more information on the LED life
When the UV source LED requires replacement it can easily performed
but it does require opening the enclosure. Contact the factory before
servicing. Alternately another service module can be purchased. Call
the HF Customer Service Department for assistance.
