Matheson 819 Series, Руководство по эксплуатации

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Tareing via RS-232:
Tare –Tareing (or zeroing) the flow meter provides it with a reference point for zero
flow. This is a simple but important step in obtaining accurate measurements. It is
good practice to “zero” the flow 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 input.
To send a Tare command via RS-232, enter the following strings:
In Polling Mode: Address$$V<Enter>
(e.g. B$$V<Enter>)
Changing From Streaming to Polling Mode:
When the meter is in the 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 flow normally, but only sends a line of data
when it is “polled”. Each unit can be given its own unique identifier or address.
Unless otherwise specified 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 filling your screen:
1. Type *@=A followed by “Enter” (or using the RS-232 communication select
menu, select A as identifier and exit the screen) to stop the streaming mode
of information. Note that the flow 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.
2. You may now poll the unit by typing A followed by “Enter”. This does an
instantaneous poll of unit 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.
3. To assign the unit a new address, type *@=New Address, e.g. *@=B. Care
should be taken not to assign an address to a unit if more than one unit is
on the RS-232 line as all of the addresses will be reassigned. Instead, each
should be individually attached to the RS-232 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.