16
RS-232 / RS-485 Output and Input
Confi guring HyperTerminal®:
Open your HyperTerminal® RS-232 / RS-485 terminal program (installed under the “Accessories” 1.
menu on all Microsoft Windows® operating systems).
Select “Properties” from the fi le menu.2.
Click on the “Confi gure” button under the “Connect To” tab. Be sure the program is set for: 19,200 3.
baud (or matches the baud rate selected in the RS-232 / RS-485 communications menu on the
meter) and an 8-N-1-None (8 Data Bits, No Parity, 1 Stop Bit, and no Flow Control) protocol.
Under the “Settings” tab, make sure the Terminal Emulation is set to ANSI or Auto Detect.4.
Click on the “ASCII Setup” button and be sure the “Send Line Ends with Line Feeds” box 5. is not
checked and the “Echo Typed Characters Locally” box and the “Append Line Feeds to Incoming
Lines” boxes are checked. Those settings not mentioned here are normally okay in the default
position.
Save the settings, close HyperTerminal® and reopen it.6.
In Polling Mode, the screen should be blank except the blinking cursor. In order to get the data streaming to
the screen, hit the “Enter” key several times to clear any extraneous information. Type “*@=@” followed
by “Enter” (or using the RS-232 / RS-485 communication select menu, select @ as identifi er and exit
the screen). If data still does not appear, check all the connections and com port assignments.
Changing From Streaming to Polling Mode:
When the meter is in the Streaming Mode (RS-485 units do not have a streaming mode), the screen is
updated approximately 10-60 times per second (depending on the amount of data on each line) so that
the user sees the data essentially in real time. It is sometimes desirable, and necessary when using
more than one unit on a single RS-232 line, to be able to poll the unit.
In Polling Mode the unit measures the fl ow normally, but only sends a line of data when it is “polled”.
Each unit can be given its own unique identifi er or address. Unless otherwise specifi ed each unit is
shipped with a default address of capital A. Other valid addresses are B thru Z.
Once you have established communication with the unit and have a stream of information fi lling your
screen:
Type *@=A followed by “Enter” (or using the RS-232 / RS-485 communication select menu, select 1.
A as identifi er and exit the screen) to stop the streaming mode of information. Note that the fl ow of
information will not stop while you are typing and you will not be able to read what you have typed.
Also, the unit does not accept a backspace or delete in the line so it must be typed correctly. If in
doubt, simply hit enter and start again. If the unit does not get exactly what it is expecting, it will
ignore it. If the line has been typed correctly, the data will stop.
You may now poll the unit by typing A followed by “Enter”. This does an instantaneous poll of unit 2.
A and returns the values once. You may type A “Enter” as many times as you like. Alternately you
could resume streaming mode by typing *@=@ followed by “Enter”. Repeat step 1 to remove the
unit from the streaming mode.
To assign the unit a new address, type *@=New Address, e.g. *@=B. Care should be taken not 3.
to assign an address to a unit if more than one unit is on the RS-232 / RS-485 line as all of the
addresses will be reassigned. Instead, each should be individually attached to the RS-232 / RS-485
line, given an address, and taken off. After each unit has been given a unique address, they can all
be put back on the same line and polled individually.
Tare –Tareing (or zeroing) the fl ow meter provides it with a reference point for zero fl ow. This is a simple
but important step in obtaining accurate measurements. It is good practice to “zero” the fl ow meter each
time it is powered up. A unit may be Tared by following the instructions on page 10 or it may be Tared
via RS-232 / RS-485 input.
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