Flowserve MX-100 Field Unit - Manual (Page 30)

MX/DDC-100 Field Unit Installation and Maintenance FCD LMENIM2329-01 – 03/11
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Installation and Configuration
3.1 Site and Network Cable Preparation
3.1.1 Site Preparation
Prepare the site and associated equipment for operation of the DDC-100 controlled MX actuators as follows:
1. Prepare a detailed site plan consisting of the following:
Actuator locations, tag numbers, DDC addresses •
Junction boxes, terminal strip locations, and tag numbers •
2. Provide free access to the MX control panel and terminal block for setup, configuration, and troubleshooting.
3. Prepare cable and label all wires. See Section 3.1.2, Network Cable Preparation.
4. nstall power and control wires in separate conduits. Shielding is not sufficient to prevent induction of stray
voltages onto signal leads from the power lines.
5. Install and verify earth grounds.
NOTE: Limitorque defines an effective local earth ground as a low impedance (less than 5 ohms) path to:
A ground electrode placed in close vicinity of the actuator that is free of ground loop currents. • OR
A safety ground that is free of ground loop currents running from the actuator back to the system ground elec- •
trode. If the signal wiring is run on aerial cable where it may be exposed to high-energy electrostatic discharge
(such as lightning), a low impedance path to ground that is capable of high current must be provided a short
distance from the actuator as described above. OR
A power distribution grid identifying the impact of power isolation to a particular actuator or group of actuators
•
should be provided.
3.1.2 Network Cable Preparation
3.1.2.1 Network Cable Connection to the Field Unit
The DDC-100 field unit is connected to the network via the MX terminal block. The network cable is connected to the
terminal block as shown in Figure 3.1.
Figure 3.1 – Network connections
NOTE:
1. Shielded, twisted-pair cables should be used.
2. Shields are connected to earth ground at one end only to avoid ground loops.
3