Cable parameters?
Cable parameters?
(OP)
Sirs, colleagues,
the CSI-2400 spectraanalyzer cable, for accelerometers with the built-in amplifiers has broken down, - it is necessary to replace. Are there any pitfalls besides that cable mast be shielded (15 ì is required)?
With the best regards,
Dmitry Semenov
the CSI-2400 spectraanalyzer cable, for accelerometers with the built-in amplifiers has broken down, - it is necessary to replace. Are there any pitfalls besides that cable mast be shielded (15 ì is required)?
With the best regards,
Dmitry Semenov





RE: Cable parameters?
ron.frend@predicon.net
RE: Cable parameters?
Doing cable repair, I have found out, to my surprise, that its screen is not connected to anything. So it cannot be grounded. Is it normal?
I would like to learn if cable entrance resistance is of importance. How to choose entrance resistance of a cable?
Regards
D. Semenov
RE: Cable parameters?
By cable entrance resisance I assume you mean nominal impedance? If so don't worry too much about it. This is only really critical if you are using charge coupled accelerometers (fairly rare nowadays) or if you are going to very high frequencies over a long cable length.
ron.frend@predicon.net
RE: Cable parameters?
Can you say how high mast be frequencies to be affected by nominal impedance of 10 m cabel? The accelerometer is a Piezo-Electric type with built in amplifier.
Regards
D. Semenov
RE: Cable parameters?
where, Fmax = maximum frequency
C = cable capacitance (picoFarads)
V = maximum output from sensor (volts) assumed @ 5V
Ic = constant current from signal conditioner (mA) - 2.4 mA
109 = scaling factor to equate units
This is for cable length in feet and cable capacitance in microfarads per foot.
If you don't want to do the calc I have attached a table to give the max transmittable frequencies for cable length and cable capacitance. Note that this is frequency transmitted along the cable - NOT Fmax. This should equate to your sampling frequency or about double your Fmax. I got this info from IMI in New York.
Cable Capacitance (picoFarads/foot)
Cable Length (feet) 16 26 30 42
10 142084 87436 75778 54127
20 71042 43718 37889 27064
30 47361 29145 25259 18042
40 35521 21859 18945 13532
50 28417 17487 15156 10825
75 18945 11658 10104 7217
100 14208 8744 7578 5413
150 9472 5829 5052 3608
200 7104 4372 3789 2706
300 4736 2915 2526 1804
400 3552 2186 1894 1353
500 2842 1749 1516 1083
1000 1421 874 758 541
2000 710 437 379 271
3000 474 291 253 180
4000 355 219 189 135
5000 284 175 152 108
10000 142 87 76 54
RE: Cable parameters?
RE: Cable parameters?
RE: Cable parameters?
Lotten, South Africa
RE: Cable parameters?
I think you are right. Applying sine signal and wiring its frequency also can do it. But to do test??? – It never came to my mind because some one should know the answer with appropriate accuracy.
Regards,
D.Semenov
RE: Cable parameters?