Thermo Scientific AquaSensors™ DataStick™ Measurement System User Guide
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The communications adapters are keyed and plug into the end of the DataStick marked “Communication Adapter”. Insert the
communications adapter until it bottoms out. Rotate the adapter until it engages with the connector. Push in gently and then tighten
the retaining ring with a 15/16-inch wrench.
Communications adapters can be inserted into the “Sensor Head” end of the DataStick but the adapter is not long enough to reach
the internal connector. Likewise, any sensor head can be inserted into the communications adapter end of the DataStick but it will
be too long for the retaining ring to be engaged.
3.4
DataStick User Interface Options
The DataStick measurement system can be connected to an AV38 Local Display, or it can be connected directly to a computer system
for interactive measurement, calibration configuration and diagnostics.
3.4.1
Network Host Protocols
When connected directly to a computer a number of different protocols are available. When using Host Communications, please refer
to the selected communications user guide for specific protocol setup and use.
3.4.2
AV38 Local Display
The AV38 is a universal display interface for DataStick sensor systems. The enclosure has ¼-DIN dimensions for easy mounting
and is rated NEMA 4X for outdoor use. It uses a liquid crystal display (LCD) with a high contrast backlight for best readability and
is powered with 24 volts DC.
The AV38 automatically recognizes the type of DataStick connected to the system and provides the
appropriate calibration, configuration and diagnostic menus. It has options for two 4-20 current loops,
two alarm/control relays and network communications to a host computer. In addition, the AV38 can
address up to 247 DataStick sensors.
DataStick sensors connected to the AV38 communicate via Modbus RTU. As such, the AV38 can
be used to select one of several DataStick sensors on the bus for display, current output reporting
and relay alarms by selecting the desired station address. When there is no DataStick sensor connected
at the selected network address, the measure screen will show dashed lines.
The AV38 can operate in “single sensor mode” with current outputs and relays, or it can be operated in “multi-sensor mode” with
digital communications to a host computer. Host communication options include, Modbus, DeviceNet, RS-485 ASCII, Profibus
and others. The host protocol is independent of the Modbus RTU protocol used by the AV38 to communicate
with the DataSticks.
In the multi-sensor mode the AV38 can be used as a switch that allows a host computer to measure calibrate, configure and diagnose
all DataSticks connected to the AV38. In this mode the AV38 measure screen displays the measure data that the host computer
is currently asking for. If the menu key on the AV38 is pressed, control of the local network of DataSticks is transferred to the AV38.
The host computer regains control after the user navigates back to the measure screen.
There are seven keys for menu navigation. The MENU key is used to toggle between the menu and the measure screen. Pressing the
Menu key provides options for calibration, configuration, communications, outputs and relays. Refer to the AV38 User guide for Details.
Host Protocol
Reference User guide to Set up Address, Baud Rate and Parity
Modbus RTU over
RS-232 or RS-485
Modbus Communications Adapter User guide (258481-001)
DeviceNet
DeviceNet Communications Adapter User guide (258482-001)
RS-232
DataStick User guide (258480-001; this document): 9600 bps, no parity, 8 data bits, 1 stop bit
USB
AquaComm USB driver with settings to 9600 bps, no parity, 8 data bits, 1 stop bit (258490-001)
Profibus
Modbus/Profibus Gateway User guide (258488-001)
Other
Look for addendums on setting up other protocols that may be configured.
