Page Comparison

4-20mA Sensor Tables

Part No.	Variant Description	Quantity	Quantity Description	Value @ 4mA	Value @ 20mA	Units	Suggested AoC
VTI21-VT1	AC Vane Relay Variant	Torque	Instantaneous Torque Exerted on the relay vane.	0	+25	m.Nm	0.2 m.Nm
VTI21-HVI	HVI Receiver Variant	Average Current	Average HVI Pulsed Current seen by the VTI21 from input channel 1.	0	600	mA	15 mA
VTI21-TI21-TX	TI21 / EbiTrack 200 Variant (TX)	Average Current	Average of upper and lower sideband current from VTI21 input channel 1.	0	5	A	0.05 A
VTI21-TI21-TX	TI21 / EbiTrack 200 Variant (RX)	Average Current	Average of upper and lower sideband current from VTI21 input channel 1.	0	200	mA	2 mA
VTI21-FS25	FS2500 Receiver Variant	Center Current	Amplitude of the FS2500 center frequency current from VTI21 input channel 1.	0	1500	mA	5 mA
VTI21-FS26	FS2600 Receiver Variant	Center Current	Amplitude of the FS2500 center frequency current from VTI21 input channel 1.	0	1500	mA	5 mA
VTI21-ACS	General Purpose AC sensing up to 25A RMS	Current	RMS current from VTI21 input channel 1.	0	25	A	0.2 A
VTI21-UM71	UM71 Variant	Current	Current at selected center frequency from VTi21 input channel 1.	0	5000	µA	100µA
VTI21-ASTER	Aster Variant	Current	Current at selected center frequency from VTi21 input channel 1.	0	5000	µA	100µA
VTI21-REED	Reed Relay Variant	Current	Current measured across the Reed relay frequency range on input channel 1.	0	5000	mA	25mA
VTI21-RFDM	Reed Relay FDM variant	n/a	none

...

VTI21-TI21 / VTI21-FS25 / VTI21-FS26

Slave Channel

VTI21 Input Channel

Quantity

Description

Typical Range

Units

Suggested AoC

1

Center Frequency

The Center frequency, in hertz, of the track circuit.

388.8 to 508.8

Hz

1 Hz

2

1

Center frequency Current	Total RMS current at the target center frequency	0 to 1000	mA	5 mA
3

1

	Lower Side Band current	Total RMS current at the target lower side band frequency	0 to 1000	mA	5 mA
4

1

Upper Side Band current	Total RMS current at the target upper side band frequency	0 to 1000	mA	5 mA
5

1In

In Band Current	Total RMS current seen by the transducer between 300 to 600 Hz	0 to 1000	mA	5 mA
6

1

Spectrogram

or Gain

Capture waveform showing the magnitude spectrum of the input signal. Use a "Triggered Capture" to acquire the Spectrogram.

When spectrum data is not being acquired, this channel shows the current amplifier gain setting

4.8 to 1228.8

Hz

NA

7

1

	Loudest Frequency	The strongest frequency, in hertz, observed in the incoming waveform.	4.8 to 1228.8	Hz	1 Hz
8

1

Total Current

Total RMS current seen by the transducer.

0 to 1000

mA

5 mA

9

2

Center Frequency

The Center frequency, in hertz, of the track circuit.

388.8 to 508.8

Hz

1 Hz

10

2

	Center frequency Current	Total RMS current at the target center frequency	0 to 1000	mA	5 mA
11

2

	Lower Side Band current	Total RMS current at the target lower side band frequency	0 to 1000	mA	5 mA
12

2

	Upper Side Band current	Total RMS current at the target upper side band frequency	0 to 1000	mA	5 mA
13

2

	In Band Current	Total RMS current seen by the transducer between 300 to 600 Hz	0 to 1000	mA	5 mA
14

2

Spectrogram

or Gain

Capture waveform showing the magnitude spectrum of the input signal. Use a "Triggered Capture" to acquire the Spectrogram.

When spectrum data is not being acquired, this channel shows the current amplifier gain setting

4.8 to 1228.8

Hz

NA

15

2

	Loudest Frequency	The strongest frequency, in hertz, observed in the incoming waveform.	4.8 to 1228.8	Hz	1 Hz
16

2

Total Current

Total RMS current seen by the transducer.

0 to 1000

mA

5 mA

VTI21-HVI

Slave Channel

VTI21 Input Channel

Quantity

Description

Typical Range

Units

Suggested AoC

1 - ANA

1

HVI Frequency

The frequency of pulses

0 to 5

Hz

0.1 Hz

2 - ANA

HVI Current

RMS Current of the pulsed waveform

0 to 1500

mA

5 mA

2

3 - ANA

1HVI Frequency

Noise Current

The

frequency of pulses

RMS current observed between pulses.

0 to

5

1500

Hz0.1 Hz3 - ANA1Noise CurrentThe RMS current observed between pulses.0 to 1500mA5 mA4 - ANA1Pulse WaveformIf this channel is requested as a capture, the VTi21 will return a high-resolution waveform of the last observed pulse

mA	5 mA
4 - DIG	Pulse Conflict	Set TRUE if pulses are observed to be bleeding through from adjacent track sections	Digital	N/A	On Change
5 - ANA	Rejection Rate	Proportion of pulses deemed not to be genuine HVI pulses	0 to 100	%	Don't push to server - for diagnostic use by Mpec only
6 - ANA	Rejection Reason	Bitfield encoding the reason a pulse was not accepted.	8 bits	N/A
7- ANA	Sensitivity	Threshold used to identify pulse events	0 to 2621440	N/A
8 - ANA	Pulse Waveform	If this channel is requested as a capture, the VTi21 will return a high-resolution waveform of the last observed pulse	0 to 1500	mA	Triggered Capture
9 - ANA	2	HVI Frequency	The frequency of pulses	0 to 5	Hz	0.1 Hz
10 - ANA		HVI Current	RMS Current of the pulsed waveform	0 to 1500	mA	5 mA
11 - ANA		Noise Current	The RMS current observed between pulses.	0 to 1500	mA

Triggered Capture

5 mA

1

12 - DIG

1

Pulse Conflict

Set TRUE if pulses are observed to be bleeding through from adjacent track sections

Digital

NA

N/A

On Change

5

13 - ANA

2HVI CurrentRMS Current of the pulsed waveform0 to 1500mA5 mA6 - ANA2HVI FrequencyThe frequency of pulses0 to 5Hz0.1 Hz7 - ANA2Noise CurrentThe RMS current observed between pulses.0 to 1500mA5 mA8 - ANA2

Rejection Rate	Proportion of pulses deemed not to be genuine HVI pulses	0 to 100	%	Don't push to server - for diagnostic use by Mpec only
14 - ANA	Rejection Reason	Bitfield encoding the reason a pulse was not accepted.	8 bits		N/A
15 - ANA	Sensitivity	Threshold used to identify pulse events	0 to 2621440		N/A
16 - ANA	Pulse Waveform	If this channel is requested as a capture, the VTi21 will return a high-resolution waveform of the last observed pulse	0 to 1500	mA	Triggered Capture

2 - DIG2Pulse Conflict

Set TRUE if pulses are observed to be bleeding through from adjacent track sectionsDigitalNAOn Change

VTI21-ACS

Slave Channel	VTI21 Input Channel	Quantity	Description	Typical Range	Units	Suggested AoC
1	1	CH 1 Current	RMS current observed on Channel 1 (output at 100 Hz, low pass filtered with cutoff of 9 Hz)	0 to 25	A	0.2 A
2	1	1	CH 1 Average Current	Average RMS current observed on Channel 1, over one second period.	0 to 25	A	0.2 A
3	2	CH 2 Current	RMS current observed on Channel 2 (output at 100 Hz, low pass filtered with cutoff of 9 Hz)	0 to 25	A	0.2 A
42	2	CH 2 Average Current	Average RMS current observed on Channel 2, over one second period.	0 to 25	A	0.2 A

...

Slave Channel	VTI21 Input Channel	Quantity	Description	Typical Range	Units	Suggested AoC
1	1	CH 1 Frequency	Channel 1 Frequency Selected	1700 to 2600	Hz	1
21		CH 1 Side Band Ratio	Ratio of lower to upper frequency (0%=all lower, 100%=all upper)	0 to 100%	%	5
31		CH 1 Raw Frequency	Simple Frequency Measurement (zero crossings)	1600 to 2700	Hz	100
4		1	CH 1 Total Current	Total current in the UM71 band	0 to 5mA	µA	100
51		CH 1 current 1700Hz	Current measured at 1700Hz	0 to 5mA	µA	100
6		1	CH 1 current 2000Hz	Current measured at 2000Hz	0 to 5mA	µA	100
71		CH 1 current 2300Hz	Current measured at 2300Hz	0 to 5mA	µA	100
81		CH 1 current 2600Hz	Current measured at 2600Hz	0 to 5mA	µA	100
91		CH 1 Spectrogram or Gain	Capture waveform showing the magnitude spectrum of the input signal. Use a "Triggered Capture" to acquire the Spectrogram.	1 to 32		1
10	2	CH 2 Frequency	Channel 1 Frequency Selected	1700 to 2600	Hz	1
112		CH 2 Side Band Ratio	Ratio of lower to upper frequency (0%=all lower, 100%=all upper)	0 to 100%	%	5
122		CH 2 Raw Frequency	Simple Frequency Measurement (zero crossings)	1600 to 2700	Hz	100
132		CH 2 Total Current	Total current in the UM71 band	0 to 5mA	µA	100
142		CH 2 current 1700Hz	Current measured at 1700Hz	0 to 5mA	µA	100
152		CH 2 current 2000Hz	Current measured at 2000Hz	0 to 5mA	µA	100
162		CH 2 current 2300Hz	Current measured at 2300Hz	0 to 5mA	µA	100
172		CH 2 current 2600Hz	Current measured at 2600Hz	0 to 5mA	µA	100
182		CH 2 Spectrogram or Gain	Capture waveform showing the magnitude spectrum of the input signal. Use a "Triggered Capture" to acquire the Spectrogram.	1 to 32		1

...

Slave Channel	VTI21 Input Channel	Quantity	Description	Typical Range	Units	Suggested AoC
1	1	CH 1 Frequency	Simple Frequency Measurement (zero crossings)	0 to 5000	Hz	1
21		CH 1 Total Current	Total current measured in the reed relay frequency range	0 to 5000	mA	10
31		CH 1 - channel 211	Total Current at 363Hz	0 to 5000	mA	10
41		CH 1 - channel 212	Total Current at 366Hz	0 to 5000	mA	10
51		CH 1 - channel 213	Total Current at 369Hz	0 to 5000	mA	10
61		CH 1 - channel 214	Total Current at 372Hz	0 to 5000	mA	10
71		CH 1 - channel 215	Total Current at 375Hz	0 to 5000	mA	10
8		1	CH 1 - channel 216	Total Current at 378Hz	0 to 5000	mA	10
91		CH 1 - channel 217	Total Current at 381Hz	0 to 5000	mA	10
101		CH 1 - channel 218	Total Current at 384Hz	0 to 5000	mA	10
111		CH 1 - spectrogram / gain	Capture waveform showing the magnitude spectrum of the input signal. Use a "Triggered Capture" to acquire the Spectrogram. note: includes only measured frequencies, which are: 363, 366, 369, 372, 375, 378, 381, 384, 408, 417, 423Hz
12	2	CH 2 Frequency	Simple Frequency Measurement (zero crossings)	0 to 5000	Hz	1
132		CH 2 Total Current	Total current measured in the reed relay frequency range	0 to 5000	mA	10
142		CH 2 - channel 211	Total Current at 363Hz	0 to 5000	mA	10
152		CH 2 - channel 212	Total Current at 366Hz	0 to 5000	mA	10
162		CH 2 - channel 213	Total Current at 369Hz	0 to 5000	mA	10
17		2	CH 2 - channel 214	Total Current at 372Hz	0 to 5000	mA	10
182		CH 2 - channel 215	Total Current at 375Hz	0 to 5000	mA	10
192		CH 2 - channel 216	Total Current at 378Hz	0 to 5000	mA	10
202		CH 2 - channel 217	Total Current at 381Hz	0 to 5000	mA	10
21		2	CH 2 - channel 218	Total Current at 384Hz	0 to 5000	mA	10
222		CH 2 - spectrogram / gain	Capture waveform showing the magnitude spectrum of the input signal. Use a "Triggered Capture" to acquire the Spectrogram. note: includes only measured frequencies, which are: 363, 366, 369, 372, 375, 378, 381, 384, 408, 417, 423Hz

...

Slave Channel	VTI21 Input Channel	Quantity	Description	Typical Range	Units	Suggested AoC Threshold
1	1	Lock-on Frequency	Ideal operating frequency track circuit	1700 to 2600	Hz	1
2		1	In-band Current	RMS current in the operating band	0-5000	uA	50
31		Principle Frequency	Loudest frequency observed (actual operating frequency)	1700 to 2600	Hz	1
41		Total Current	broad-and RMS current	0-5000	uA	50
51		1700 Hz Band Current	RMS current in the 1700 Hz band	0-5000	uA	50
61		2000 Hz Band Current	RMS current in the 1900 Hz band	0-5000	uA	50
71		2300 Hz Band Current	RMS current in the 2100 Hz band	0-5000	uA	50
81		2600 Hz Band Current	RMS current in the 2300 Hz band	0-5000	uA	50
91		Gain / FFT	Pre-amp Gain as AoC, Spectrogram is acquired as a triggered capture	10	Hz	NA
10	2	Lock-on Frequency	Ideal operating frequency track circuit	1700 to 2600	Hz	1
112		In-band Current	RMS current in the operating band	0-5000	uA	50
122		Principle Frequency	Loudest frequency observed (actual operating frequency)	1700 to 2600	Hz	1
132		Total Current	broad-and RMS current	0-5000	uA	50
142		1700 Hz Band Current	RMS current in the 1700 Hz band	0-5000	uA	50
152		2000 Hz Band Current	RMS current in the 1900 Hz band	0-5000	uA	50
162		2300 Hz Band Current	RMS current in the 2100 Hz band	0-5000	uA	50
172		2600 Hz Band Current	RMS current in the 2300 Hz band	0-5000	uA	50
1182		Gain / FFT	Pre-amp Gain as AoC, Spectrogram is acquired as a triggered capture	10	Hz	NA

...

note: only one input channel is supported.

Slave Channel

VTI21 Input Channel

Quantity

Description

Typical Range

Units

Suggested AoC

1

Frequency

Simple Frequency Measurement (zero crossings)

0-1000

Hz

50

2

1

	Total Current	Total current measured in the reed relay frequency range	0-5A	mA	100
3

1

FFT	FFT for each monitored Channel		Hz	NA
4

1

	channel 4	Energy at 803.25Hz	0-5A	mA	100
5

1

	channel 16	Energy at 702.5Hz	0-5A	mA	100
6

1

	channel 17	Energy at 697.5Hz	0-5A	mA	100
7

1

	channel 19	Energy at 687Hz	0-5A	mA	100
8

1

	channel 20	Energy at 682.5Hz	0-5A	mA	100
9

1

	channel 26	Energy at 611.75Hz	0-5A	mA	100
10

1

	channel 27	Energy at 607.75Hz	0-5A	mA	100
11

1

channel 36	Energy at 505Hz	0-5A	mA	100
12

1

	channel 38	Energy at 493.5Hz	0-5A	mA	100
13

1

	channel 39	Energy at 488Hz	0-5A	mA	100
14

1

	channel 47	Energy at 419.75Hz	0-5A	mA	100
15

1

channel 48	Energy at 410.25Hz	0-5A	mA	100
16

1

	channel 83	Energy at 446Hz	0-5A	mA	100
17

1

channel 84	Energy at 533.75Hz	0-5A	mA	100
18

1

channel 92

Energy at 842Hz

0-5A

mA

100

Versions Compared

Old Version 19

New Version Current

Key

4-20mA Sensor Tables

VTI21-TI21 / VTI21-FS25 / VTI21-FS26

VTI21-HVI

VTI21-ACS