Lighthouse RLPC 0.1m, Operating Manual

Page: 28 / 118

Lighthouse REMOTE Liquid Particle Counter (MODBUS Output) Operating Manual
3-4 248083227-1 Rev 8
Communication Ports
WARNING:
When
daisy chaining multiple
instruments, connect IN
ports only to OUT ports.
DO NOT connect an IN
port to another IN port.
Doing so will damage the
sensor and void the
warranty.
The RS232/485 IN port incorporates Serial and MODBUS
communications to allow short distance point-to-point RS232 or long
distance multi-point RS485 communications.
The RS232 protocol is provided for quick simple cable connections to a
standard PC COM port and is used for single-unit communications
only.
The RS485 protocol is provided for industrial applications with
multiple devices on the same bus and requires an adapter when used
with a PC. The RS485 IN and OUT connectors allow easy connections
using standard CAT 5 patch cables commonly used for office LANs.
Connecting the counter to a PC via RS485 requires an RS485 to RS232
converter, cables, connectors and terminator; please contact a
Lighthouse Sales Representative for the LWS RS485 converter kit.
For more information, please see chapter on “Communications” on
page 4-1.
RS485 Adapter Cable
WARNING:
Failure to
use the Adapter Cable in
a daisy-chain network
may damage the RLPC
and void its warranty.
An RS485 Adapter Cable is available as an optional accessory and
must be used to connect the RLPC to an RS485 daisy-chain network.
The adapter prevents damage to the instrument when it is used in daisy-
chain networks. Plug it into the RS232/485 IN port before connecting
the network cable to the RLPC. See Figure 3-4.
Figure 3-4 RS485 Adapter Cable
Note:
Use of the Adapter
Cable for RS232 or RS485
Hub connections may not
provide the desired results.
If the RLPC will be used in a point-to-point RS232 connection, the
Adapter Cable should not be used. RS232 communication to the RLPC
will be blocked if the adapter is in place.
If the RLPC will be used in a star configuration using an RS485 hub,
the Adapter Cable should not be used if the hub is supplying power to
the instrument. Power to the RS232/485 IN port will be blocked if the
adapter is in place.