Specifications

24 Maxim Industrial Solutions
Programmable logic controllers (PLCs)
Fieldbus functions
In the fieldbus module the control-
ler converts the backplane protocol
to the fieldbus protocol. Universal
asynchronous receiver-transmitters
(UARTs) define the fieldbus data
rates, ensure data integrity, and
interface to either the RS-485 or
PROFIBUS transceivers.
Harsh conditions typical of industrial
applications can make protecting
the interface cabling and devices
a challenge. It is crucial, therefore,
that both the device(s) and system
withstand harsh conditions. Only in
this way can one ensure that the PLC
system’s signal integrity and system
reliability are maintained.
To ensure that the system is pro-
tected in harsh industrial environments,
PLC designers need to incorporate
quite specific safeguards:
• Protection from high ESD: up to
±35kV (HBM) and ±20kV (Air Gap,
IEC 61000-4-2)
• Fault protection: tolerance to
shorts up to ±80V
• Isolation to allow large common-
mode ground differentials
• Line termination to reduce reflec-
tions on the cables
• Automotive temperature grade
(-40°C to +125°C)
The fieldbus is connected to the PLC backplane by the fieldbus module. For a list of Maxim's recommended PLC solutions, please go to: www.maxim-ic.com/plc.
HOT-SWAP
CONTROLLER
VOLTAGE
MONITORS
ISOLATED POWER SUPPLY
CAN
RS-232
PROFIBUS
FIELDBUS
UART
RS-485
FAULT
PROTECTION
ISOLATION
CONTROLLER
BACKPLANE
RS-485
TERMINATION
ETHERNET
LVDS
= MAXIM SOLUTION