3. Cabling
3-31
TI 32P01J10-01EN
3.5 Connecting Signal Cable
The terminal blocks or connectors of I/O modules are the interface of the eld signals.
When connecting the eld signals to I/O modules via a dedicated cable and a terminal
board, the terminal board becomes the interface of the eld signals.
CAUTION
Do not ground the secondary side of the eld power supply connected to the digital input module
SDV144 style code S1 to S3.
Process I/O Signal Connection
• Power, control bus, and signal cables must be separately laid. Avoid laying them in parallel.
• In case of using multicore cables for eld wiring, do not share one multicore cable with I/O
modules of dierent voltage types (i.e. 48 V DC and 24 V DC).
48 V DC: SDV53A
24 V DC: SDV144, SDV521, SDV531, SDV541
• The use of group-shielded twisted-pair cables is recommended for analog signal input
specically in order to prevent induction noise. A twisted-pair cable pitch of 50 mm or less
should be used and the shielded cables must be grounded.
• The use of twisted-pair cables is also recommended for digital signals.
• The twisted-pair cable has the following advantages over a solid wire:
• More exible for easy curving and cabling in limited spaces.
• With good contact and durable in using a solderless contact.
• Signal cables must be clamped so that their weight does not aect terminals.
• Use solderless lug or pressure clamp terminal contact when process I/O signals are
connected with terminals.
• Be careful when laying cables so as not to place excessive force on the cables.
When mixing AI and DO in the same multi-core cable (N-IO I/O Unit)
When mixing analog input (AI) signal and digital output (DO) signal in the same multi-core cable,
take the following inuence from DO pulse diagnostics or ON/OFF operation into consideration.
· The accuracy for Analog input function may be worse by several tens of μA depending on
the type, length of a cable and DO load current.
· A delay may occur in updating the HART event.
Solderless Lug
CAUTION
• Use the solderless contact with an insulation covering.
• Use the solderless contact and crimp tools of the same manufacturer.
• Use correct-size crimp tools according to cable sizes.
Oct. 5, 2018-00
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