West Control Solutions Pro-EC44 - Manual (Page 116)

Pro-EC44 2-Loop Graphical Profile Controller & Recorder
Pro-EC44 Product Manual - 59540-1 October 2013 Page 109
20 Serial Communications
Supported Protocols
Communication with a Modbus RTU or Modbus TCP master device is possible if the
appropriate communications module is fitted in option slot A. An RS485 Module is required
for Modbus RTU. An Ethernet Module is required for Modbus TCP.
The instrument can also act as
“setpoint master” over RS485 for multi-zone applications. In
this mode the unit continuously sends its setpoint value using Modbus broadcast messages.
Master mode is not available with Ethernet module.
To protect the EEPROM from excessive write operations, the 6 most recent parameter write
requests are held in standard RAM. All data is written to EEPROM at power-down or if
another parameter is changed. Avoid continuously changing more than 6 parameters.
All models also have a configuration socket for bench setup via the PC configuration
software prior to installation. An RS232 to TTL lead (available from your supplier) is required
in order to use this socket. A front mounted USB port is available on some models; this can
also be used to configure the instrument or to transfer recorder or profile files via a USB
memory stick.
RS485 Configuration
The RS485 address, bit rate and character format are configured via the front panel from the
Comms Configuration sub-menu or by using the PC Configurator software.
Data rate: 4800, 9600, 19200, 38400, 57600 or 115200 bps
Parity: None (default), Even, Odd
Character format: Always 8 bits per character.
Device Address: See below.
RS485 Device Addressing
The instrument must be assigned a unique device address in the range 1 to 255. This
address is used to recognise Modbus queries intended for this instrument. With the
exception of globally addressed broadcast messages, the instrument ignores Modbus
queries that do not match the address that has been assigned to it.
The instrument will accept broadcast messages (global queries) using device address 0 no
matter what device address is assigned to it. No response messages are returned for
globally addressed queries.
Ethernet Configuration
For Modbus TCP communications (Modbus over Ethernet), the Ethernet IP address can
either be assigned by a Dynamic Host Configuration Protocol (DHCP), BootP or AutoIP
server on the network, or manually assigned using the IP address allocation software tool.
Refer to the PC Software section of this manual on page 235 for more information about
setting the IP address.
The supported data rates 10/100BASE-T (10 or 100 Mbps) are automatically detected.