What is the maximum instrument primary cable to used.
You are talking about maximum cable length ? or types of cables ?
Maximum size of primary cable for instrument.
INSTRUMENTATION SIGNAL CABLES
Instrumentation Cables are specially designed to transmit signals without any external interference. They are used in Data Acquisition Systems, connections to Instruments, Computer Networking, PA Systems, Digital / Analog Control / Measuring & Communication Systems.
Construction - Cores, pairs, triads or quads
Voltage Grade - Up to 1100 V
Conductor - Electrolytic grade copper Bare / Tinned Solid / Stranded/Flexible conductors
Range - 0.5 / 0.75 / 1.0 / 1.5 / 2.5 Sq mm up to 48 Pair
Primary Insulation - General purpose PVC / Heat Resistant PVC / LDPE / XLPE / PTFE / Fibre Glass /
FEP / Silicone Rubber
Screening - Individual and/or overall with following options - Aluminum Mylar/Copper Tape with Tinned Copper Drain Wire or Braided with Bare or Tinned or Nickel Plated or Silver Plated Copper
Inner Sheath - PVC / HRPVC / FRPVC / FRLS PVC / ZHFR / LSF
Armouring - GI round Wire / Flat strip or Wire Braiding
Outer Sheath - PVC / HRPVC / FRPVC / FRLS PVC / ZHFR / LSF
Rip Cord - For easy removal of sheath
Standards - BS-5308 Part-1 & 2, BS-7655, IEC-189 (1 & 2), VDE-0815 & 0816 and BS EN 50288
Additional Features - Communication pairs, Bi-colour extrusion
Also see
https://www.anixter.com/content/dam/Anixter/Catalogs/EMEA-Wire-and-Cable-Handbook/EMEA-WC-Sec-4.pdf
Why is it that the instrument primary and secondary cable are twisted?