Projecta IM2000 Instructions d'exploitation télécharger pdf (Page 23)

Recommended Wiring

Rules of Wiring and Shielding

Noise is always present in a system that involves both high power and small

signal circuitry. Regardless of the power configuration used for your system,

there are some wiring and shielding rules that should be followed to keep the

noise-to-signal ratio as small as possible.

Rules of Wiring

 Power supply and motor wiring should be shielded twisted

pairs run separately from signal carrying wires.

 A minimum of 1 twist per inch is recommended.

 Motor wiring should be shielded twisted pairs using 20-gauge

wire or, for distance greater than 5 feet, 18 gauge or better.

 Power ground return should be as short as possible to

established ground.

 Power supply wiring should be shielded twisted pairs. Use

18 gauge wire if load is less than 4 amps, or 16 gauge for

more than 4 amps.

 Do not “Daisy-Chain” power wiring to system components.

Rules of Shielding

 The shield must be tied to zero-signal reference potential. In

order for shielding to be effective, it is necessary for the

signal to be earthed or grounded.

 Do not assume that earth ground is true earth ground.

Depending on the distance to the main power cabinet, it

may be necessary to sink a ground rod at a critical location.

 The shield must be connected so that shield currents drain

to signal-earth connections.

 The number of separate shields required in a system is equal

to the number of independent signals being processed plus

one for each power entrance.

 The shield should be tied to a single point to prevent ground loops.

 A second shield can be used over the primary shield,

however, the second shield is tied to ground at both ends.

Recommended Power Supply Cables

Power supply cables must not run parallel to logic level wiring as noise will be

coupled onto the logic signals from the power supply cables. If more than one

driver is to be connected to the same power supply, run separate power and

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Projecta IM2000 Instructions d'exploitation Page 23