Instruction Manual

Planning a DH II Cable System
Chapter 5
5-11
Table 5.C
Follow
these guidelines for grouping conductors
Group conductor cables fitting this description: Into this
category:
Examples:
Control & ac Power - highpower conductors that are more
tolerant of electrical noise than category 2 conductors and
may also cause more noise to be picked up by adjacent
conductors.
• corresponds to NEC article725 class 1
• corresponds to IEEE levels 3 (low susceptibility) &
4 (power)
Category 1
• ac power lines
• highpower digital ac I/O lines - to connect ac I/O
modules rated for high power and high noise
immunity.
• highpower digital dc I/O lines - to connect dc I/O
modules rated for high power or with input circuits
with long timeconstant filters for high noise rejection.
They typically connect devices such as hardcontact
switches, relays, and solenoids.
Signal & Communication - lowpower conductors that are
less tolerant of electrical noise than category 1 conductors
and should also cause less noise to be picked up by
adjacent conductors (they connect to sensors and
actuators relatively close to the I/O modules).
• corresponds to NEC article725 classes 2 & 3
• corresponds to IEEE levels 1 (high susceptibility) &
2 (medium susceptibility)
Category 2
• analog I/O lines and dc power lines for analog
circuits
• lowpower digital ac/dc I/O lines - to connect to I/O
modules that are rated for low power such as
lowpower contactoutput modules.
• lowpower digital dc I/O lines - to connect dc I/O
modules that are rated for low power and have input
circuits with short timeconstant filters to detect short
pulses. They typically connect to devices such as
proximity switches, photoelectric sensors, TTL
devices, and encoders.
• communication cables (remote I/O, extendedlocal
I/O, DH+, DH485, RS232C, RS422, RS423
cables) - to connect between processors or to I/O
adapter modules, programming terminals,
computers, or data terminals.
Intraenclosure - Interconnect the system components
within an enclosure
• corresponds to NEC article725 classes 2 & 3
• corresponds to IEEE levels 1 (high susceptibility) &
2 (medium susceptibility)
Category 3
• lowvoltage dc power cables - provide backplane
power to the system components
• communication cables - to connect between system
components within the same enclosure
NOTE: Remote I/O, DH, and DH+ networks must be made of catalog number 1770CD cable or a cable from the approved vendor list.
DH485 networks must be made of a cable from the approved vendor list.