C2® Certified Cable
Hardy C2 Certified Cable has been designed specifically for the electrically and mechanically harsh environments found in Process Weighing applications. While many process variables are transmitted at a 0-10 volt or 4-20 milliamp level, signals from load or force sensors are typically one thousand times smaller, or 0-0.010 volts.
A ten pound change on a 100,000 pound scale would correspond to a signal change of 0.000001 volts (1 micro volt). Therefore, cabling
must protect against electrical noise common in the plant environment.
It is also imperative that moisture not enter the cable as it would increase capacitance and allow coupling of voltage from the excitation wires to the signal wires. The coupling of voltage causes “drifting” weight indications. Use of improper cable between even the finest load sensors and instrumentation will yield poor weighing results.
The costs and time delays of removing and replacing improper weighing system cable are prohibitive. To insure an effective weighing system, always specify Hardy C2 Certified Cable.
A. The thick (0.060") outer jacket protects signal leads from minor nicks and cuts, and helps keep moisture and contaminants out. The vinyl material used is flexible for conduit bends and slides more easily in long conduit runs. Additionally,this material resists many corrosive substances.
B. 36 gauge braided tinned copper shield provides better than 85% coverage and tight braid angles to reduce the chance of outside electrical noise reaching the signal leads. Unlike other process measurements, incremental changes in weight correspond to signal changes typically in the range of 0.0000001 volts (0.1 micro volt). Without proper shielding, common plant electrical noise can cause fluctuation and incorrect weight readings.
C.A mylar barrier reduces the chance of moisture reaching the signal leads should the cable be nicked. Moisture between signal leads increases the capacitance between signals and results in cross coupling of voltages and incorrect weight readings.
D. The 22 gauge wire is stranded for reliability in bends and is color coded for easy installation.
E. Two wires make up a twisted pair to reduce capacitance for C2 signals and provide a constant cable impedance.
C2 Cable Wiring