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 impedance and about 5 ns/m signal propagation speed.
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 the rest 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|