Effects of Long Wires - Revision history

Mparadis: /* Introduction */

2019-10-22T18:48:55Z

Introduction

← Older revision		Revision as of 18:48, 22 October 2019
Line 1:		Line 1:
	[[Category:Troubleshooting]]		[[Category:Troubleshooting]]
	==Introduction==		==Introduction==
	The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and ~~[[Electricity Primer#Cable_Gauges_for_Terminal_Blocks\|~~gauge]] of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.		The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and gauge of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.

	==Materials Used for Calibration==		==Materials Used for Calibration==

Mparadis at 19:20, 5 May 2017

2017-05-05T19:20:16Z

← Older revision		Revision as of 19:20, 5 May 2017
Line 1:		Line 1:
			[[Category:Troubleshooting]]
	==Introduction==		==Introduction==
	The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and [[Electricity Primer#Cable_Gauges_for_Terminal_Blocks\|gauge]] of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.		The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and [[Electricity Primer#Cable_Gauges_for_Terminal_Blocks\|gauge]] of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.

Mparadis at 18:53, 5 May 2017

2017-05-05T18:53:09Z

← Older revision		Revision as of 18:53, 5 May 2017
Line 1:		Line 1:
	~~[[Category:General Documentation]]~~
	==Introduction==		==Introduction==
	The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and [[Electricity Primer#Cable_Gauges_for_Terminal_Blocks\|gauge]] of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.		The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and [[Electricity Primer#Cable_Gauges_for_Terminal_Blocks\|gauge]] of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.

Mparadis: /* Calibration for Non-Ratiometric Sensors */

2017-04-18T15:40:00Z

Calibration for Non-Ratiometric Sensors

← Older revision		Revision as of 15:40, 18 April 2017
Line 38:		Line 38:

	==Calibration for Non-Ratiometric Sensors==		==Calibration for Non-Ratiometric Sensors==
	The difference in doing the same calibration with non-ratiometric sensors comes from the fact that the voltage drop on VCC makes no difference (within reason). Instead, the current (amperage) consumption only introduces an offset on ~~SensorValue~~.		The difference in doing the same calibration with non-ratiometric sensors comes from the fact that the voltage drop on VCC makes no difference (within reason). Instead, the current (amperage) consumption only introduces an offset on the sensor voltage.

	To calculate the offset, D:		To calculate the offset, D:

	<math>D = \text{~~SensorValueLong~~} - \text{~~SensorValueShort~~}\!</math>		<math>D = \text{VoltageLong} - \text{VoltageShort}\!</math>

	If D = 0, there will be no effect from the longer cable. If D < 0, repeat the calibration. This would mean that by using the longer cable, a more accurate measurement was obtained compared to using the shorter cable. Otherwise if D > 0, in operation, replace ~~SensorValue~~ in the formula for this sensor with:		If D = 0, there will be no effect from the longer cable. If D < 0, repeat the calibration. This would mean that by using the longer cable, a more accurate measurement was obtained compared to using the shorter cable. Otherwise if D > 0, in operation, replace voltage in the formula for this sensor with:

	<math>\text{~~NewSensorValue~~} = \text{~~SensorValue~~} + D\!</math>		<math>\text{NewVoltage} = \text{Voltage} + D\!</math>

	==In Conclusion==		==In Conclusion==
	This should be repeated with each sensor or wiring harness in order to be as accurate as possible. Any change in resistance or current consumption may affect the accuracy of each individual sensor differently.		This should be repeated with each sensor or wiring harness in order to be as accurate as possible. Any change in resistance or current consumption may affect the accuracy of each individual sensor differently.

Mparadis: /* Procedure */

2017-04-18T15:38:53Z

Procedure

← Older revision		Revision as of 15:38, 18 April 2017
Line 19:		Line 19:
	==Procedure==		==Procedure==
	#Plug the sensor into the 8/8/8 through the short cable.		#Plug the sensor into the 8/8/8 through the short cable.
	#Note the sensor voltage. We will call this VoltageShort		#Note the sensor voltage. We will call this '''VoltageShort'''
	#Plug the sensor into the 8/8/8 through the long cable.		#Plug the sensor into the 8/8/8 through the long cable.
	#Note the sensor voltage. We will call this VoltageLong.		#Note the sensor voltage. We will call this '''VoltageLong'''.
	'''Note:''' It is very important that the conditions under which both measurements were taken do not change! For example, if using the Temperature Sensor, the actual temperature that was being measured did not change between measurements.		'''Note:''' It is very important that the conditions under which both measurements were taken do not change! For example, if using the Temperature Sensor, the actual temperature that was being measured did not change between measurements.

Mparadis: /* Calibration for Ratiometric Sensors */

2017-04-18T15:38:33Z

Calibration for Ratiometric Sensors

← Older revision		Revision as of 15:38, 18 April 2017
Line 27:		Line 27:
	This calibration only works if the sensor does not change its current (amperage) consumption over time for the measured property (for example, the 1121 does).		This calibration only works if the sensor does not change its current (amperage) consumption over time for the measured property (for example, the 1121 does).

	'''Note:''' The calibration for ratiometric sensors will be much more accurate the farther ~~SensorValueShort~~ is from ~~500~~. The closer ~~SensorValueShort~~ is to ~~500~~, the less accurate		'''Note:''' The calibration for ratiometric sensors will be much more accurate the farther VoltageShort is from 2.5V. The closer VoltageShort is to 2.5V, the less accurate the calibration will be.
	the calibration will be.

	The formula to calculate the gain factor, C, is:		The formula to calculate the gain factor, C, is:

	<math>C = \frac{\text{~~SensorValueShort~~} - ~~500~~}{\text{~~SensorValueLong~~}-~~500~~}\!</math>		<math>C = \frac{\text{VoltageShort} - 2.5}{\text{VoltageLong}- 2.5}\!</math>

	If C = 1, then there will not be any noticeable effect from the longer cable and the normal formula for the sensor can be used. If C < 1, repeat the calibration. This would indicate that by using a longer cable, a more accurate measurement was obtained compared to using the shorter cable. Otherwise if C > 1, replace the ~~SensorValue~~ in the formula for the sensor with:		If C = 1, then there will not be any noticeable effect from the longer cable and the normal formula for the sensor can be used. If C < 1, repeat the calibration. This would indicate that by using a longer cable, a more accurate measurement was obtained compared to using the shorter cable. Otherwise if C > 1, replace the voltage in the formula for the sensor with:

	<math>\text{~~NewSensorValue~~} = (\text{~~SensorValue~~} - ~~500~~) * C + ~~500~~\!</math>		<math>\text{NewVoltage} = (\text{Voltage} - 2.5) * C + 2.5\!</math>

	==Calibration for Non-Ratiometric Sensors==		==Calibration for Non-Ratiometric Sensors==

Mparadis: /* Procedure */

2017-04-18T15:04:15Z

Procedure

← Older revision		Revision as of 15:04, 18 April 2017
Line 19:		Line 19:
	==Procedure==		==Procedure==
	#Plug the sensor into the 8/8/8 through the short cable.		#Plug the sensor into the 8/8/8 through the short cable.
	#Note the ~~SensorValue~~. We will call this ~~SensorValueShort~~		#Note the sensor voltage. We will call this VoltageShort
	#Plug the sensor into the 8/8/8 through the long cable.		#Plug the sensor into the 8/8/8 through the long cable.
	#Note the ~~SensorValue~~. We will call this ~~SensorValueLong~~.		#Note the sensor voltage. We will call this VoltageLong.
	'''Note:''' It is very important that the conditions under which both measurements were taken do not change! For example, if using the Temperature Sensor, the actual temperature that was being measured did not change between measurements.		'''Note:''' It is very important that the conditions under which both measurements were taken do not change! For example, if using the Temperature Sensor, the actual temperature that was being measured did not change between measurements.

	==Calibration for Ratiometric Sensors==		==Calibration for Ratiometric Sensors==

Mparadis at 11:06, 19 October 2016

2016-10-19T11:06:34Z

← Older revision		Revision as of 11:06, 19 October 2016
Line 4:		Line 4:

	==Materials Used for Calibration==		==Materials Used for Calibration==
	*A short ~~sensor~~ cable, such as our 60cm ~~sensor~~ cable		*A short Phidget cable, such as our 60cm Phidget cable
	*A long ~~sensor~~ cable that you wish to use		*A long Phidget cable that you wish to use
	*The sensor you will be using with the long cable		*The sensor you will be using with the long cable
	*The Phidget Interface Kit 8/8/8		*The Phidget Interface Kit 8/8/8
Line 15:		Line 15:
	*Both cables are at the same temperature.		*Both cables are at the same temperature.
	**Most conductors (not all) tend to increase their internal resistance as their temperature increases. The greater the temperature difference between the cables is, the higher the error in calibration will be.		**Most conductors (not all) tend to increase their internal resistance as their temperature increases. The greater the temperature difference between the cables is, the higher the error in calibration will be.
	*The long ~~sensor~~ cable uses the same gauge of wire for both VCC and GND.		*The long Phidget cable uses the same gauge of wire for both VCC and GND.

	==Procedure==		==Procedure==

Mparadis: /* Introduction */

2012-08-21T18:41:47Z

Introduction

← Older revision		Revision as of 18:41, 21 August 2012
Line 1:		Line 1:
	[[Category:General Documentation]]		[[Category:General Documentation]]
	==Introduction==		==Introduction==
	The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and [[Cable_Gauges_for_Terminal_Blocks\|gauge]] of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.		The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and [[Electricity Primer#Cable_Gauges_for_Terminal_Blocks\|gauge]] of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.

	==Materials Used for Calibration==		==Materials Used for Calibration==

Mparadis: /* Introduction */

2012-08-21T18:41:11Z

Introduction

← Older revision		Revision as of 18:41, 21 August 2012
Line 1:		Line 1:
	[[Category:General Documentation]]		[[Category:General Documentation]]
	==Introduction==		==Introduction==
	The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and gauge of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.		The purpose of this guide is help keep highly accurate measurements when using long wires to connect sensors. Depending on the length and [[Cable_Gauges_for_Terminal_Blocks\|gauge]] of the wire, the internal properties of the wire – its electrical resistance and inductance – can reduce the accuracy of the measurement. It is important to calibrate the formulae used to compensate for the errors due to these effects. The errors are negligible when using shorter wires, but they can affect the accuracy if you are sending the measured signal over a large distance. Depending on how accurate you need to be, it may be acceptable to not have to calibrate any formulae.

	==Materials Used for Calibration==		==Materials Used for Calibration==