E-m-hc2-accessories_24 – ROTRONIC HC2 User Manual

Page 10

E-M-HC2-accessories_24

Rotronic AG
Bassersdorf, Switzerland

Document code

Unit

Accessories and Parts
for probes, indicators and transmitters

Instruction Manual

Document Type

Page 10 of 23

Document title

Networking notes:

A Modbus network and a RS-485 network are physically identical but cannot be mixed due to the

difference between the communication protocols.

The internal configuration of the HC2 probe determines which communication protocol (RO-ASCII or

Modbus) will be used by the combination of probe and adapter. RO-ASCII is the factory default
communication protocol for the HC2 probe and is automatically used whenever the probe is interrogated
by the HW4 software.

The protocol used by the probe when not communicating with HW4 can be changed between RO-ASCII
and Modbus with the HW4 software > Device Manager. After interrogating or configuring the probe with
HW4, cycle power to the probe to enable the selected protocol.

When connecting the probe to a RS-485 network be sure that the probe is configured to use the RO-ASCII

protocol.

RS-485 Compatibility: the RO-ASCII protocol is not compatible with the protocol used by the previous

generation of ROTRONIC products. Do not connect legacy products and the adapter / HC2 probe
combination to the same RS-485 multi-drop network.

Within a RS-485 network, the combination of HC2 probe and adapter is always seen as a slave. The RS-

485 address is that of the HC2 probe. The factory default is address 0. The master is another ROTRONIC
device with an interface combination such as RS-485 and USB or RS-485 and TCP/IP.

Please note that each device connected to a RS-485 network, including the master device, must have a
unique address. As long as the factory default address of the HC2 probe (0) has not been changed, the
HW4 software will automatically change the address of the probe to the next available address at the time
that the probe is added as a slave to a RS-485 network monitored by HW4.

The RS-485 address of the HC2 probe can also be changed manually with the HW4 software Device
Manager.

Each adapter can be powered either by an individual voltage source or centrally powered from the network

with a single voltage source. In the case of a network that both provides power and transmits data, a
shielded cable with two twisted pairs is required for the main bus.

User to supply all necessary connecting hardware such as T-connection box, terminal box, etc.

Prior to using the adapter, we strongly recommend consulting the following documents:

E-M-HW4v3-Main, E-M-HW4v3-F2-001 and E-M-AC3000-CP