PD2-6400
Helios High Voltage & Current Meter
www.predig.com
13
DIGITAL COMMUNICATIONS
Modbus
®
RTU Serial Communications
With onboard RS-485 serial communication
, the PD2-6400
can communicate with any Modbus
master
device using the
popular Modbus communications protocol that is included in
every Helios. In addition to the typical Modbus capabilities of
reading PVs and writing set points, below are some examples
of other things that can be done with the meter’s Modbus
communications:
•
Send a 6-character message to the lower display upon an
event
• Convert a digital value to a 4-20 mA signal
• Remote user control (i.e. change set points, acknowledge
alarms)
•
Input a Modbus digital PV (in place of analog input)
• Remote override of any, or all, relays and analog outputs
Additional Communication Modules
In addition to RS-485 communications which is a standard
feature, the Helios is available with serial communications
modules for RS-232 and USB.
PDA7485-I
RS-232 to
RS-422/485
Isolated Converter
PDA8485-I
USB to
RS-422/485
Isolated Converter
*All adapters and connectors supplied with appropriate cables.
Modbus PV Input
Remote Message
ON-BOARD DIGITAL INPUTS AND
OUTPUTS
The PD2-6400 includes five (5) digital inputs and four (4) digital
outputs standard. Since the Helios is a large display meter it is
often mounted in areas where it is not convenient to access the
programming buttons. The digital inputs can be set up to mimic
the four programming buttons on the Helios meter, thus making
it possible to mount remote buttons for programming in a more
convenient location. In addition, the digital inputs can also be
used to reset the total, operate the tare feature, reset the tare,
and more. The digital outputs can be used to drive alarming
devices or as a means to communicate alarm conditions with
a PLC.
V+ V- F4 COM
2
1
4
3
2
1
I+
I-
O1 O2 O3 O4 G
I
1
I
2
I
3
I
4
+5
Ground
5 VDC
4 Digital Inputs
& 4 Digital Outputs
F4 Terminal for
Digital Input
See page 17 for more details on what can be done with the
digital inputs and outputs.
Click here for more information on
the Helios’s Modbus capabilities
2
5
A
V
