DJYVP3 * 2 * 1 twisted pair computer cable

2017-06-29

Computer signal cable, the choice of small dielectric constant dielectric polyethylene insulation. Using the twisted pair, the screen, the total screen (or three-wire group twisted, group shielding, the first screen screen) and other forms of the computer's AC power cord to be a good shield, and seriously terminated its shield, The high-permeability material is spirally wound around the outer layer of the cable and then a layer of plastic holster as a protective layer. This shielding effect is better, but it also with the cable terminal impedance, the characteristic impedance of the incident signal and the direction of the incident signal and other factors, because the terminal impedance and characteristic impedance on the cable may exist in the standing wave has an impact.
In addition, the relative length of the cable has an effect on the sensing level across the cable shield relative to the wavelength of the external electromagnetic wave. The performance of the connector used and the degree of bending of the cable, but also affect the cable shielding effect of the important factors. When the cable is bent into a corner, the coverage near the inner half is the largest, and the coverage on the outer radius side is significantly reduced.
For the end of the shield of the cable, in general, all other parts of the shield shall be insulated from the ground except for the specified ground, for the purpose of preventing unwanted grounding, since the shield is connected to the enclosure or base Any accidental contact can produce a small arc discharge there, forming noise that affects the operation of the circuit, and the shield can not be used as a loop conductor for the signal.
Copper and aluminum as a cable shield is better, because it has a lot of reflection of electromagnetic waves. For cables with very high spectral components, a multi-point grounding method can be used to ground the shields at both ends of the cable at the same time. If applicable, add a connector to ground the shield in the middle.
For shielded audio-sensitive circuits can only be grounded at one end, to this type of cable shield must be insulated from ground to prevent unnecessary grounding. It has the characteristics of low dielectric loss, strong transmission signal capability, good anti-jamming performance, reliable transmission of weak analog signal or digital signal, and can be widely used in the detection and control of power generation, metallurgy, petroleum, chemical industry and textile industry. Systems or automated instrumentation, as well as general industrial computers.
Computer Signal Cable - DJYVP; DJYVRP; DJYPVP; DJYJVRP; DJYPVP22.
1. Rated voltage: AC 300V and below;
2. Wire core maximum operating temperature: 70 ℃ and 105 ℃ two;
3. Minimum ambient temperature: fixed laying -40 ℃, non-armored not less than 6 times the cable diameter, armor or copper shield is not less than 12 times the cable diameter.
DJYPV - Polyethylene insulated copper wire braided sub - shielded PVC sheathed electronic computer cable, DJYVP - polyethylene insulated copper wire braided shielded PVC sheathed electronic computer cable.
Description:
(1) Flame retardant (oxygen index greater than 30) cable need to add code before the code "ZR"; For example: ZR-DJYPV ZR-DJYPVP and so on.
(2) armored type (steel armor) cable in the lower right corner of the model code "22"; for example: DJYPV22 DJYPVP22 and so on.
The cable is mainly used for AC or DC 300V and below the working system, 500V and below to work properly.
Two pairs of five-phase shielded cable should be twisted into a four-wire structure, and clockwise color order: orange, white, green, black.
Twisted on the shield
Shielded twisted pair should be wrapped before the shield to protect the insulation from damage, with polyester film thickness of not less than 0.025mm, wrapped around a layer of cover is not less than 20% of the bandwidth.
Braided shield with a diameter of not more than 0.16mm soft round copper wire or tinned copper wire weaving, weaving, the density should not be less than 80%, the braid does not allow the overall connector, exposed copper head should be cut from the root, no glitches or thread Braided layer surface.
Wrap around the shield
The use of single-layer wrap, cap rate should not be less than 20% of the bandwidth, and immediately adjacent to the metal layer into a not less than 0.50mm copper wire or tinned copper wire to do the connection line.
When the aluminum / plastic composite tape is used for the shielding material, the performance of the aluminum / plastic composite tape shall be in accordance with YD / T723.2, and its thickness should be not less than 0.18mm.
When the aluminum / plastic composite tape is used for the shielding material, the copper tape performance should meet the requirements of GB / T11091 and its thickness is not less than 0.09mm.
Twisted on the shield, there should be insulation layer, the insulation layer can be used extrusion PVC insulation, extrusion thickness of 0.5mm (not assessment), can also be used PVC or polyester film wrapped insulation layer, cap rate is not less than 25% of the bandwidth, PVC tape thickness should be not less than 0.2mm, polyester film thickness should be not less than 0.025mm.
Into a cable
The twisted pair should be concentrically twisted into the cable, the outermost stranded for the right, the adjacent layer twisted to the contrary, the cable pitch is not greater than 20 times. The twisted pair pairs are numbered from the inner to the outer layers starting from 1 in the order of natural numbers clockwise.
After the cable should be overlapping to wrap a layer of thickness of not less than 0.20mm of the PVC tape, no total shielded cable with a cap of not less than 25% of the bandwidth, the total screen shielded cable with a cover ratio of not less than 40% And pack the second floor. The cable is allowed to be filled with non-absorbent wetting material in order to round the cable.
Total shield
Cable shielding should be used copper wire or tinned copper wire braid shield, can also be used with copper or aluminum tape wrapped shield. Electromagnetic shielding should be used not less than 0.09mm thickness of the copper band left wrapped around the copper belt with a thickness of not less than 0.2mm galvanized steel band to the right around the package, wrapped around the cover rate of not less than 20% in the copper belt below Should be placed in a vertical not less than 0.5mm copper wire or tinned copper wire to do the connection line.