6700 Portable Sampler User Manual - Isco

Command Driven Mode
Charts showing the Command
Driven screens appear in
Figure 49, Command Driven
Screens on page 134.
61
__ ft SUCTION LINE
__ BOTTLES
PUMP TUBE ALARM
DONE
6700 SAMPLERS
PRESSURIZED LINES
The sampler can obtain samples from pressurized lines, as long
as the line pressure remains below 15 PSI (pounds per square
inch). Pressures greater than 15 PSI may prevent the sampler
from purging the suction line; moreover, extreme pressures can
force liquid past the pump, even when the pump is not running.
For more consistent sample volumes from lines under constant
pressure, calibrate the samples. Isco does not recommend sampling
from pressurized lines.
COMMAND DRIVEN OPERATION
The 6700 controller can be placed in a mode where it is a slave to
an external controller. The external controller is responsible for
determining when to take a sample, how much volume to pump,
and where to put the sample. The external controller directly
interfaces to the sampler via an RS-232 communications port at
2400 baud, 8 data bits, no parity, and 1 stop bit. A comma-separated-value
protocol is used by the external controller to make
requests, and by the sampler to report results. Use a standard
computer connect cable (see Appendix E) toconnectthesampler’s
interrogator port and the external controller.
To enable the command driven mode, press 6 7 0 0 . 3 at the
main menu. The sampler then displays its current command
driven state (normally WAITING TO SAMPLE) and is ready to
respond to valid commands from the external controller. From the
WAITING TO SAMPLE screen, press the (Stop) key to check
the sampler setup (screen 61). To change the setup, use the arrow
keys to select the item to modify, and press enter. Select DONE to
save the changes and return to command driven operation.
To return to normal sampler operation, press 6 7 0 0 . 1 for
standard programming or 6 7 0 0 . 2
for extended programming
while at the sampler setup screen (screen 61).
While in the command driven mode the sampler will be quite
limited in its functionality. Some of the limitations are:
No modules
No partition data
No sample event log
No reports
No Flowlink communication
No programmable I/O
No sample calibration
No rinses or retries
Auto suction head (head based on line fill counts and line
length)
Purge times become a function of the line length
Event is sent during the entire pump cycle.
The 6700 Sampler will respond to three commands: GET STA-
TUS, TAKE SAMPLE, and SET TIME. All commands must
include the instruction set and a checksum value.
103