Helios PD2-6080/PD2-6081 Modbus
®
Scanners
Instruction Manual
30
Serial Communications (
serial
)
The scanner is equipped with RS-485 Modbus RTU
serial communications.
The
Serial
menu is used for programming the
Scanner ID, Baud Rate, Transmit Delay, Parity, and
Byte-to-Byte Timeout parameters.
The scanner may be connected to a PC for initial
configuration via the on-board USB connection. For
ongoing digital communications with a computer or
other data terminal equipment, use the RS-485
connection with the appropriate serial converter; see
•
DO NOT
connect any equipment to the RJ45
M-LINK connector. Otherwise damage will occur
to the equipment and the meter.
•
DO NOT
disconnect the RJ45 connector located
to the left of the power terminal block. Doing so
will disable the on-board digital I/O, and the
RS-485 serial communications.
When using more than one scanner in a multi-drop
mode, each scanner must be provided with its own
unique address. The scanner address (Scan ID) may
be programmed between 1 and 247.
The transmit delay may be set between 0 and 4999
ms; this value must be less than (Poll Time/# of PVs).
The parity can be set to even, odd, or none with 1 or 2
stop bits.
When setting up the scanner to run on a Modbus
system, the devices must be programmed with
matching Baud Rate and Parity. Failure to match up
the network devices’ parameters may result in
communication breaks.
Notes:
1. The byte-to-byte timeout setting may be adjusted
to fix communication errors with slow devices.
2. The Transmit Delay of the Master must be
greater than the Snooper or the slave devices
being polled.
