Cable Requirements
What cable types are recommended for constructing measuring lines with RS-485 and CAN interfaces?
For constructing measurement networks with RS-485 and CAN interfaces, it is recommended to use twisted pairs with 120 Ohm wave impedance and about 5 ns/m signal delay difference.
When choosing a cable it is also important to take into consideration its operating conditions. Generally, fixed measuring systems use cables with operating range from −40°C (outdoor version). When constructing small-scale measuring lines which will not operate in high interference conditions, it is possible to use unshielded cable; in other cases it is recommended to use screened cable. When choosing a cable, give preference to cables with stranded wire as conductor.
Table of recommended cables for establishing measuring lines
| Number Of Pairs | AWG | Cable Description | Outer Ø (mm) | Op. Temp. (°С) | Purpose |
|---|---|---|---|---|---|
| 4 | 26 | Shielded twisted pair SSTP (S/FTP), category 7 (600MHz), 4 couples (26AWG), multi-wire (patch), LSZH (305 m) | 6.5 | -20 to 70 | for measuring lines up to 100 m |
| 2 | 26 | Flame retardant twisted pair high-speed transfer cable (bunched cable that resist fire propagation) 2×2×0.40 | 8.8 | -60 to 80 | for measuring lines up to 100 m |
| 2 | 24 | Interface cable RS-422/485, 2×2×24 AWG SFTP , 120 Ohm, in PVC sheath for operating in wide temperature range | 7.3 | -45 to 70 | for measuring lines up to 100 m |
| 2 | 22 | Teldor 9FY9F2V101 Interface cable RS-422/485, 2×2×22 AWG SFTP, 120 Ohms, multi-wire (stranded), SF/UTP, -35 С С- +70, FR-PVC, comparable to Belden 8132 | 6 | -35 to 70 | for measuring lines up to 200 m |
| 2 | 22 | Hyperline RS-SF2-O Interface cable RS-422/485, 2×2×22 AWG SFTP, multi-wire (stranded), (patch) 120 Ohm, in PVC sheath, cold-resistant | 10.3 | -55 to 70 | for measuring lines up to 200 m |
| 2 | 15 and 18 | Trunk cable for networks DeviceNet, 2×18 AWG + 2×15 AWG S/STP (IEC 60332-1) in fire-resistant, low smoke halogenless compound sheath (FR-LSZH) 9822T18108 | 12 | -20 to 75 | for measuring lines up to 1,000 m |