Micromod MOD: MODCELL Multiloop Processor 2002N Model C and Associated Hardware - Manual (Page 56)

MODCELL Multiloop Processor
COMMUNICATIONS CONNECTIONS
4.2.2 2033N RS-232 Communication for Modbus
The 2033N RS-232 Communication module is a driver/receiver that can be used for a
point-to-point Modbus network. This module meets all RS-232C and V.28 specifications,
has a ±9V output swing with a +5V supply, and has ±30V receiver input levels. Its field
connection terminals are optically isolated from the instrument circuitry, and the maximum
network cable length is 50 feet.
This module supports the Extended Modbus protocol which provides full communications
functionality between Modcell instruments, and between the instruments and the
Application Builder software.
! CAUTION Be sure this module is wired properly before applying power.
Although this module is isolated, it can be damaged if excessive
voltage is applied across the input pins. This module is not a
drop-in replacement for the ICN module (2030N), and will be
damaged if ICN level voltages are applied to the input pins.
Connections for a typical Modbus network using this module are shown in Figure 4-2.
Either a personal computer or this module can act as the modbus master.
The address switches on the module permit assignment of an address to each module on
the network. Addresses 1 through 247 ($01 through $F7 in hexadecimal) are supported
by the Modbus protocol.
The COMM DEFAULTS switch provides for communication with the module when its
configuration is unknown. When the switch is set at YES, a set of default parameters is
invoked. The parameters are: 9600 baud, no parity, one stop bit, eight data bits, and the
port has slave functionality.
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