Flowserve MX Electronic Actuator - Manual (Page 29)

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Limitorque MX Electronic Actuator FCD LMENIM2306-06 – 10/13
flowserve.com
After installation is complete and prior to operation, inspect the network cable and its connection to each field unit for
the following:
There should not be:
• Nicks in the insulation—this can cause a short to the grounded shield.
• Cut strands in a stranded conductor—this can cause a poor connection and eventually an open circuit.
• Cable armor shorted to the cable shield/drain wire—this may not be at ground potential and could be subject to
lightning surges.
• Shield/drain wire grounded at more than one end of each cable segment (the section between each adjacent actuator
on the loop). This will avoid ground loop problems.
• Ground/earth connection except at true ground potential and effective at all times.
3.3.8 Foundation Fieldbus Installation
Ensure that the Foundation Fieldbus cable type is Belden 3076F, or another cable that is within 5% of the following
specifications.
• Characteristic impedance: 100 ohms @ 31.25 kHz
• Resistance, each wire: 7.32 ohms/1000 ft
• Attenuation: 0.914 dB/1000 ft @ 39 kHz
• Capacitative Unbalance: 3.6 pF/ft
Using other cables may result in decrease of internodal distance and/or an increase in communication error.
Particular care should be taken when terminating twisted-pair shielded cables in a FF control network. Avoid nicks, cuts,
or abrasions in the insulation of data communication cables, since this may result in inadvertent ground connection.
Also, excess cable should be cut, not coiled or looped, to prevent noise induction into the network.
Cable Preparation
Prepare the network cable for connection to the MX actuator terminal block as follows in Figure 3.15 through 3.18.
Table 3.5 details connections for Foundation Fieldbus.
Table 3.5 – Foundation fieldbus connections
Terminal Block Number FF Function
4 DATA (-)
5 DATA (+)
The shield must be connected to ground or earth at only one place. The cable shield is generally grounded at the power
conditioner.
Reference the Fieldbus Foundation Application Guide 31.25 kbit/s Wiring and Installation guide for more information on
network wiring.
a CAUTION: Strip stranded conductors carefully; do not damage the strands. This will weaken the conductor.
Do not nick conductors when stripping away the insulation. Nicking stresses the conductor and can cause the
conductor to break. This type of damage may not be apparent and failure can occur later without warning.