Brookfield DV-III Rheometer User Manual
Page 76
Brookfield Engineering Laboratories, Inc.
Page 76
Manual No. M/98-211-A0701
Model
mm
LV
LV
2.5LV
4L
5LV
5L
RV
RV
RV
1R
RV
2R
HA
HA
2HA
3A
2.5HA
4A
HB
HB
2HB
3B
2.5HB
4B
5HB
5B
Table 1 - DV-III+ Model Decoding
Invalid cmd received
1
x
x
x
x
x
x
x
Diagnostics error
x
x
1
x
x
x
x
x
Motor circuit error
x
x
x
1
x
x
x
x
Auto-zero complete
x
x
x
x
1
x
x
x
Motor speed = 0
x
x
x
x
x
1
x
x
Motor On (Energized)
x
x
x
x
x
x
1
x
Control circuitry enabled
x
x
x
x
x
x
x
1
Table 2 - Status Byte
Note: These values are not updated in the status byte when the listed condition occurs. They are
made available when the computer next sends a command that includes the status byte in the re-
sponse. The flags are cleared when the condition causing a flag to be set has been resolved or by re-
enabling (E command) the DV-III+.
The DV-III+ must first be issued the E(nable) command to enable control circuitry and ascertain its
current status. The DV-III+ will respond with an echo of the E(nable) command and will append the
current status <ss> of the DV-III+. This 2-digit status byte will provide information as to the
rheometer's internal working condition and capability to continue with or to accept new tasks.
The Z(ero) command is used to "zero" the DV-III+ 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+'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+
will have to perform all the calculations required for viscosity, shear stress and shear rate, etc. The
DV-III+ 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+ 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.