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RS485 Network Guidelines
The instrument uses RS485 as its main digital communications link. RS485 is often used in an industrial setting as a small
device network. There are some installation guidelines to follow when configuring an RS485 network with this instrument.
See the Modbus and SDI-12 Reference Guide.
DB-9 Diagram
Pin
Signal Name
1
Carrier Detector
DCD
2
Receive Data
RXD
3
Transmit Data
TXD
4
Data Terminal Ready
DTR
5
Signal Ground/Common
GND
6
Data Set Ready
DSR
7
Request to Send
RTS
8
Clear to Send
CTS
9
Ring Indicator
RI
Communication Overview
The instrument can be programmed to use either Modbus or SDI-12. Modbus and SDI-12 cannot be used at the same time.
The protocol that is in use will block communication of the other.
See the Aqua TROLL 400 Modbus and SDI-12 Reference Guide for registers and
programming information.
Prior to connecting the instrument to the controller, you must configure communication settings using the Comm Kit Software
and the Communication Device.
Device ID
Device ID for the AquaTROLL 400 is 18.
Data Quality IDs and the Sensor Health Table
Each sensor on the Aqua TROLL 400 instrument is associated with a corresponding Data Quality ID register. (See the Aqua
TROLL 400 Modbus and SDI-12 Guide to set up registers.) When Data Quality ID registers are configured, they will return
Data Quality ID numbers that can help you to troubleshoot issues with the system or verify that readings are normal. See the
Sensor Health Table.