H3C S5120-SI Installation Manual

Also see for S5120-SI Series: Quick start guide Installation manual Operation manual Configuration guide Command reference

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H3C S5120-SI Installation Manual Manual pdf 10 page image

2• Lasting low relative humidity can cause washer contraction and ESD and cause problemsincluding loose mounting screws and circuit failure.• High temperature can accelerate the aging of insulation materials and significantly lower thereliability and lifespan of the switch.For the temperature and humidity requirements of different models, see Table 7 and Table 8.CleanlinessDust buildup on the chassis might result in electrostatic adsorption, which causes poor contact ofmetal components and contact points, especially when indoor relative humidity is low. In the worstcase, electrostatic adsorption can cause communication failure.Table 1 Dust concentration limit in the equipment roomSubstance Concentration limit (particles/m3)Dust ≤ 3 x 104 (no visible dust on the tabletop over three days)NOTE:Dust diameter ≥ 5 μmThe equipment room must also meet strict limits on salts, acids, and sulfides to eliminate corrosionand premature aging of components, as shown in Table 2.Table 2 Harmful gas limits in the equipment roomGas Maximum concentration (mg/m3)SO 2 0.2H2 S 0.006NH3 0.05Cl2 0.01EMIAll electromagnetic interference (EMI) sources, from outside or inside of the switch and applicationsystem, adversely affect the switch in the following ways:• A conduction pattern of capacitance coupling.• Inductance coupling.• Electromagnetic wave radiation.• Common impedance (including the grounding system) coupling.To prevent EMI, perform the following tasks:• If AC power is used, use a single-phase three-wire power receptacle with protection earth (PE)to filter interference from the power grid.• Keep the switch far away from radio transmitting stations, radar stations, and high-frequencydevices.• Use electromagnetic shielding, for example, shielded interface cables, when necessary.