Brookfield DV-III Ultra Rheometer - Manual (Page 127)

Brookfield Engineering Laboratories, Inc. Page 127 Manual No. M/98-211-B0104
Brookfield Engineering Laboratories, Inc. Page 127 Manual No. M98-211-E0912
The Z(ero) command is used to "zero" the DV-III Ultra rheometer. The value returned <zzzz> is usually
in the range of 03F0 hex to 0400 hex. This number should be retained and subtracted from every future
returned torque reading to obtain the actual rheometer torque in percent.
The rheometer torque value and current temperature may be obtained by issuing the R(etrieve) command.
The DV-III Ultra's response to this command is to echo the command: R(etrieve) and then follow it
with 8 hex digits comprising the current values for the rheometer torque <qqqq> and the temperature
probe reading <tttt>. Any control program written to exploit the output of the DV-III Ultra will have
to perform all the calculations required for viscosity, shear stress and shear rate, etc. The DV-III Ultra
will be directed to run at a given speed through the use of the V(elocity) command. Unlike the two
previous commands, this command requires the parameter <vvvvv> which contains the value for the
desired speed. The DV-III Ultra responds to this command by repeating the command: V(elocity)
and appending the status byte <ss> which will, amongst other things, inform the calling program as to
whether the motor was turned on and/or whether the desired speed was attained.
RS-232 Output During The Yield Test
All output that occurs immediately before and after the yield test is described in Section III.4. That
pre- and post- test output is sent out both the serial (RS-232) and parallel ports. When using the
Brookfield Computer Cable (Brookfield part # DVP-80), the DV-III Ultra will output a data string
during the actual yield test run. This data is ONLY sent out to the RS-232 port for use with the
EZ-Yield TM software.
The following output is sent to the serial (RS-232) port at the end of every Base Increment period:
xxxxxx:yy.yy:ttt.t:zz.zz
Where the delimiter between all fields is a colon (:) character and
xxxxxx = The Base Increment count in hexadecimal format, padded with leading zeroes.
This is the time, in milliseconds that each reading was taken in the instrument.
yy.yy = % Torque value. % Torque is output with a resolution of 0.01% and a maximum
of 99.99%.
ttt.t = Temperature in °C.
zz.zz = Delta Torque (%). This is the actual change in percent torque, measured from the
previous reading, calculated at the end of each Base Increment period.