dataTaker - Data Loggers, Powerful and Flexible Data Acquisition & Data Logging Systems

Channel options allow the function of the dataTaker channels to be tailored in various ways including

input configuration

sensor excitation

ADC gain

statistical reporting

special calculations

variable assignment

destination of data

data format

The various channel options available are listed in the Channel Options Table overleaf, and are described in the following pages.

Channel options relate both to individual channels and to sequences of channels, and are specified in brackets following the channel type label in the general formats

ntype(options)
n..mtype(options)
module:ntype(options)
module:n..mtype(options)

where

n                 is a single channel number
n..m             is a sequence of channels
module         is the module number, 0 for the dataTaker and
                   1 or 2 for successive Channel Expansion Modules
type             is the signal type identifier
options         is a list of one or more channel options

The option list may include one or more channel options. If more than one channel option is listed, then the individual channel options are separated by a comma (no spaces allowed), and may in any order.

When a sequence of channels is specified, then the channel options are applied to all channels in the sequence.

The channel options apply only to the channel specification in which they are found. When the same channel is included more than once in a schedule list or channel list, then each inclusion is treated as a separate entity and each can have different channel options.

The channel options are applied in a particular order during execution of the channel, irrespective of the order of specification in the options list.


Channel Options Table

 

Category

Option

Function

Mutual Exclusion

Range of Option

Applicn
Order

Input termination

T

Terminates +, -- inputs with 1 MOhm to ground

]

 

1

 

U

Un-terminates +, -- inputs

]

 

1

Resistance

4W

Configures channel for 4 wire measurement

   

1

Single ended input

X

Use SE Ref terminal as common

]

 

1

 

2V

Use internal 2.500V Vref as common

]

 

1

Gain

GLn

Gain lock

 

1, 10, 100

1

Attenuation

A

Attenuation

]

 

1

 

NA

No attenuation

]

 

1

Excitation

G

Guard signal

]

 

1

 

V

Voltage excitation, approx 4.5V via 1KOhm

]

 

1

 

I

Current excitation, 250 uA

]

 

1

 

II

Current excitation, 2.500mA

]

 

1

 

N

No excitation

]

 

1

Special

Esn

Extra ADC samples when reading channel

 

0 to 15

1

 

Mx:y

Special input signal routing

 

0 to 255

1

Resetting

R

Reset counter, timer, channel variable, after read

   

2

Scaling

f.f

Channel factor

 

±1e18

2

 

Yn

Polynomial

]

1 to 20

3

 

Sn

Span

]

1 to 20

3

 

Fn

Intrinsic function

]

1 to 6

3

Data manipulation

DF

Difference dX

]

 

4

(cannot use in alarms)

RC

Rate of change dX/dT

]

 

4

RS

Rate of change X/dT

]

 

4

 

IB

Integrate (X-dX/2)*dT

]

 

4

Reference channels

TR

Thermocouple reference junction temp channel

]

 

5

(not logged or displayed)

TZ

Thermocouple reference zero channel

]

 

5

BR

Bridge excitation measurement channel

]

 

5

Statistical

AV

Average

]

 

6

(cannot use in alarms)

SD

Standard deviation

]

 

6

MX

Maximum

]

 

6

 

MN

Minimum

]

 

6

 

TMX

Time of maximum

]

 

6

 

TMN

Time of minimum

]

 

6

 

DMX

Date of maximum

]

 

6

 

DMN

Date of minimum

]

 

6

 

INT

Integral

]

 

6

 

Hx:y:n..mCV

Histogram, x=lower limit, y=upper limit

]

x, y ±1e18

6

Variables

=nCV

Assign data to variable

]

1 to 100

7

 

+=nCV

Add data to variable

]

1 to 100

7

 

--=nCV

Subtract data from variable

]

1 to 100

7

 

*=nCV

Multiply variable by data

]

1 to 100

7

 

/=nCV

Divide variable by data

]

1 to 100

7

Data formatting

FFn

Fixed point with n decimal places

]

0 to 6

8

 

FEn

Exponential with n significant digits

]

0 to 6

8

 

FMn

Mixed FF and FE with n decimal places

]

0 to 6

8

 

ìtextî

Channel label

 

ascii text

8

Bar graph

BGx:y

Bar graph

 

±1e18

8

Data destination

NR

No return

   

8

 

NL

No log

   

8

 

ND

No display

   

8

 

W

Working channel

   

8


Using DeTransfer, channel options are specified in a bracketed list following the channel(s) these apply to as follows

1V(V)

where a single channel option which specifies that a 4.5 VDC excitation is to be output from the excite terminal of channel 1 before reading the input signal.

And

5PT385(4W,200.0,"Steam Temp.",FF0)

where a number of channel options for an RTD temperature sensor that is connected to the dataTaker for measurement by the 4 wire resistance measurement mode (4W). The temperature sensor has a 200 Ohm resistance at 0o C. The channel data is to be labelled "Steam Temp." for output, and the data is returned with a resolution of 1oC (FF0).

The dataTaker will return data as

Steam Temp.  266 Deg C

instead of the default

5PT385  265.7 Deg C

DeLogger supports many of the channel options from the Channel Properties dialog, where the options are grouped under various tabs. The Channel Properties dialog is opened by right clicking on a selected channel, and selecting Channel OptionsÖ which then displays a list of the key option groups. Select the required option group to open the Channel Properties dialog.

 

 

Mutually Exclusive Options

Most of the channel options fall into separate function categories, and the individual channel options within each of these categories are mutually exclusive. These categories and the ranges of mutual exclusivity are indicated in the Channel Options Table.

Only one of the channel options in each category can be specified in a channel options list. If more than one mutually exclusive channel option is defined, then the last defined option is applied.

Order of Application

There is a particular order of application for channel options, and is indicated in the Channel Options Table. The dataTaker applies channel options in this order, irrespective of the order in which they are included in the options list.

The order ensures for example that the sensor is excited before a polynomial is applied, and that the polynomial is applied before the data is averaged, etc.

The Channel Options Grouping

The different channel options fall into a number of categories of related functions. The channel options and their function are described in the following sections.

Options for Input Signal Configuration and Mode of Operation

Several options are available for the input configuration, and the mode of operation of the analog input channels. The input configurations and modes of operation options are as follows

Input Terminated

T ñ the analog input is terminated to dataTaker ground via a 1 MΩ resistance during measurement, providing an input bias current path.

Differential inputs of voltage, current, frequency, thermocouples and analog state are terminated by default. Single ended inputs for these signals are not terminated by default.

Input Unterminated

U ñ the analog input is disconnected or unterminated from the 1 MΩ terminating resistor during measurement. The input impedance is > 100MΩ when inputs are unterminated. The signal source must provide an input bias current of approx 5nA.

Use of this option is appropriate to un-terminating input types for which termination is the default configuration, such as for differential voltage, current, frequency, thermocouples, analog state, etc.

4 Wire Measurement

4W ñ selects the four wire method for measurement of resistance, RTD, bridge, and thermistor inputs. This configuration provides full compensation for resistance of cable wires between the sensor and the dataTaker.

The default resistance measurement is three wire.

External Common

X ñ the SE REF terminal is to be used as the 'common' terminal for measurement of externally referenced single ended inputs. The active side of the single ended signals are connected to the +ve, ñve or T terminals of the analog input channels, and the non active sides are commoned and connected to SE REF.

The SE REF terminal is a high impedance input (>100 MOhm), similar to the analog input channels.

The default is to measure single ended inputs with reference to dataTaker ground.

2.5 Volt Common

2V ñ an internal 2.5 Volt reference is to be used as the 'common' for various signal types, rather than an applied common or dataTaker ground.

This can extend the single ended input voltage range of the dataTaker to the common mode voltage limits (0 - 4.5VDC). However the measurement is sensitive to ground loop noise, and should not be used when precision is required.

Examples

Using DeTransfer, the following channel options for example

2+V(X,U)

commands the dataTaker to measure voltage between the positive terminal of analog channel 2 and the SE REF terminal, with the internal 1 MΩ terminating resistor unterminated.

2R(4W)

commands the dataTaker to measure the resistance connected to analog input channel 2 by the 4 wire measurement method.

Using DeLogger, the Unterminate channel option for example is set from the Channel Properties dialog in the Program Builder as follows

 

Options for ADC Gain

The Analog to Digital Converter of the dataTaker automatically selects gain to suit the level of the measured signal. However this can be disabled and a constant gain set for individual channels. This is often used to provide constant resolution of data as the signal moves between two or three ranges of the logger.

The dataTaker 505,605,515 and 615 also have an internal attenuator which can optionally be selected. This attenuator is common to all analog input channels, and has an attenuation ratio of 214.6 : 1.

Gain Lock

GLn ñ Inhibits auto-ranging and presets or locks the amplifier gain to n, where n is 1, 10 or 100.

Internal Attenuation

A ñ Selects the internal attenuators in the dataTaker 505,605,515 and 615. The high voltage input type has the attenuators selected by default.

NA ñ Deselect the internal attenuators in the dataTaker 505,605,515 and 615 where their selection is a default channel option.

Examples

Using DeTransfer, the following channel options for example

1:1V(A)
1I(100,A)

selects the internal attenuators for measurement of the voltage on the Channel Expansion Module 1 channel 1.

Using DeLogger, the Internal Attenuation channel option for example is set from the Channel Properties dialog in the Program Builder as follows

 

Options for Excite Terminal Function

The Excite terminal of the analog input channels can provide sensor excitation voltages, currents, and guard voltage outputs.

The excitation conditions are established 10mS before the channel is sampled. This time is the channel settling time, can be varied by 7SV and Parameter10.

The Excite terminal options are mutually exclusive, and if more than one is specified then the last option is implemented.

Guard Output

G ñ Provide a guard output voltage from the Excite terminal when the channel is selected for reading. The guard voltage is equal to the input common mode voltage via approximately 3 KΩOhm, and is used when the signal source has high output impedance where cable leakage is a problem.

Voltage Output

V ñ Output approximately 4.5 Volt via 1 KOhmΩ from the Excite terminal when the channel is selected for reading. This can be used to power sensors, and is applied by default for the monolithic temperature sensors and ratiometric bridge circuits.

Note:This voltage is not regulated and may drift with temperature. The 5 Volt sw output terminal can be used as a regulated 5 volt supply.

250.00 µA Current Output

I ñ Output a precision 250.00 µA excitation current from the Excite terminal when the channel is selected for reading. This can be used to excite resistive type sensors, and is applied by default for resistance, nickel RTDs, and thermistors.

The current source is very stable over a wide temperature range.

2.500 mA Current Output

II ñ Output a precision 2.500 mA excitation current from the Excite terminal when the channel is selected for reading. This can be used to excite resistive type sensors, and is applied by default for platinum and copper RTDs, strain gauges and bridge inputs.

The current source is very stable over a wide temperature range.

No Output

N  - Switches the Excite terminal off if the default channel option for the channel type includes excitation.

When the Excite terminal is not used for sensor excitation, it can be used as a single ended input which can be referenced to the Analog Return or SE REF input. This single ended input option is not supported in the dataTaker 50.

Examples

Using DeTransfer, the channel options for example

5V(V)

commands the dataTaker to measure a differential voltage on analog input channel 5, from a sensor which is powered by 4.5 Volt output from the Excite terminal during sampling.

2V(II)

commands the dataTaker to measure the voltage drop across a resistive element, excited by a 2.500 mA current output from the Excite terminal during sampling.

Using DeLogger, the Excite terminal channel options for example are set from the Channel Properties dialog in the Program Builder as follows

 

Special Channel Options

Several special channel options are available to facilitate sampling of particular analog signals.

Extra Samples

ESn ñ The Extra Sample channel option allows an analog channel to be sampled multiple times, and the result averaged and returned. The n specifies the number of extra samples, in the range of 1 ñ 15. The extra samples are taken successively, and do not involve any additional setup time.

This channel option is useful for reducing the effects of noise in the signal, and for increasing resolution.

Vibrating wire frequency measurement by the dataTaker 515 and 615 is the result of 10 successive samples by default (ES defaults to 9).

Signal Routing

Mx:y ñ This channel option allows for special input signal routing, and is primarily used during development for special signals, but can also be used for measuring the internal battery voltage and battery current as follows

0V(M18:156,101.0)             returns the battery voltage

0I(M18:220,-0.22)             returns the battery current

A positive battery current indicates charging, and a negative battery current indicates discharging.

Examples

Using DeTransfer, the channel option for example

5FW(ES7)

commands the dataTaker to sample a frequency of a vibrating wire strain gauge on analog input channel 5 seven times and return the average. The default is to sample nine times.

Using DeLogger, the Extra Samples channel option for example is set from the Channel Properties dialog in the Program Builder as follows

 

Options for Resetting to Zero

R ñ The reset channel option is used for resetting counters, digital outputs, warning outputs, System Timers and Channel Variables after execution or scanning. The reset can also be used to pulse digital and warning outputs.

Examples

Using DeTransfer, the following channel option for example

1C(R) 2DSO(1000,R)=1

commands the dataTaker to reset counter 1 to zero after reading, and to set digital output channel 2 high for 1000 mS then reset the output to low.

Options for Scaling of Channel Data

The channel option list can also specifying scaling and linearizing of the raw data sampled from the input and counter channels. Scaling and linearizing of the raw data may be specified as follows

Channel Factor or Scale Factor

f.f ñ a single channel factor may be declared, which is used to scale the sampled data. The channel factor is a decimal value, and can be declared in floating point or exponential format.

The channel factor has a particular purpose for different signal types, such as an attenuation factor for voltage signals, magnitude of the current shunt for current signals, the resistance at 0.0 Deg C for RTDs, the threshold for analog state, etc.

For channel input types where the channel factor has no defined purpose, then the channel factor can be used for direct scaling.

The polynomial, span and intrinsic function scaling options are all mutually exclusive, and if more than one is specified then the last option specified is implemented. The channel factor however is not mutually exclusive to these, and can be used in conjunction with a polynomial, span or intrinsic function, to linearise data.

Polynomials

Yn ñ a polynomial can be specified, which is used to convert the sampled data according to linear or curvilinear calibrations. The polynomial must be declared prior to use (See Section III ñ Scaling Data - Polynomials, Spans and Functions)

Spans

Sn ñ a span can be specified, which converts the sampled data according to linear calibrations. The span must be declared prior to use (See Section III – Scaling Data - Polynomials, Spans and Functions)

Intrinsic Functions

Fn ñ a predefined function can be specified, which scales the sampled data. (See Section III ñ Scaling Data - Polynomials, Spans and Functions)

Examples

Using DeTransfer, the following channel options for example

1V(5.5)

commands the dataTaker to measure the differential voltage signal connected to analog channel 1, and multiply this by 5.5. This is appropriate to scaling an externally attenuated voltage.

3V(Y2)

commands the dataTaker to measure the differential voltage signal connected to analog channel 3, and to linearise this by the defined polynomial Y2.

8V(10.5,Y9)

commands the dataTaker to measure the attenuated differential voltage signal connected to analog channel 8, to scale the data by the attenuation factor of 10.5, and to linearise this by polynomial Y9.

Using DeLogger, data scaling channel options via spans and polynomials are selected in the Program Builder from the walking menus after a channel is defined as follows

 

 

and Intrinsic Functions are also selected in the Program Builder from the walking menus after a channel is defined as follows

 

Options for Data Manipulation

Channels can be read, and special data returned which relates to the previous readings for that channel. These options include difference, rate of change and integration.

Data manipulation options cannot be used for the input channels of Alarms. Instead, the channel must be included in a Triggered Schedule where the channel is read, the data is manipulated, and the result is assigned to a Channel Variable (nCV). The Channel Variable can then be tested in the Alarm statement.

Difference

DF ñ Returns the difference between the latest reading and the previous reading for the channel.

Rate of Change

RC ñ Returns the rate of change between the last reading and the previous reading, with respect to the sample times (x/dt). The time base is in seconds, and data is returned in units/sec for the signal type.

Rate of Change 

RS ñ Returns the rate of change between the latest reading and the previous reading, with respect to the sample times (dx/dt), where the original data is already a difference (for example resetting counters). The time base for rate of change is in seconds, and the data is returned in units/sec for the signal type.

Integrate

IB ñ Returns the integral between the latest reading and the previous reading, with respect to the sample times. The time base for the integral is in seconds, and the data is returned in units.secs for the signal type.

Examples

Using DeTransfer, the following channel option for example

4PT385(200.0,DF)

commands the dataTaker to return the difference in temperature between successive readings of a PT385 with 200Ω zero resistance, connected to analog channel 4.

Using DeLogger, the Data Manipulation channel options are available on the Manipulation tab of the Channel Properties dialog in the Program Builder.

 

Options for External References 

Thermocouple and bridge inputs require external references under some circumstances, which are used in the calculation of the related measurement inputs.

The reference channels are scanned, and the data retained internally for use as references or for compensation of other channel types. The reference channels do not return, log or display any data.

The reference channel inputs are identified by channel options as follows

Thermocouple Reference Temperature

TR ñ Indicates that the input is an external thermocouple reference junction temperature sensor. It is used as an option for the RTD, thermistor and monolithic temperature sensors, which can all be used as thermocouple reference junction temperature sensors.

If a thermocouple is junction compensated by an external conditioning device, then use 11SV(TR) as the reference channel. The System Variable 11SV returns mathematical zero.

Thermocouple Zero Reference Channel

TZ ñ Indicates that the input is an external thermocouple zero voltage reference. It is used as an option for the voltage input type.

Bridge Excitation Voltage Channel

BR ñ Indicates that the input is an external supply voltage for a bridge input, and is to be used as the bridge reference for ratiometric bridge measurement.

Options for Statistical Evaluation

Input channels can be read at intervals, and produce a statistical summary of the data at longer intervals (see Section III ñ Statistical Sub Schedule).

Channels which have statistical channel options are sampled at the interval defined by the Statistical Sub Schedule, and the statistical data is calculated and returned at the associated Repeating Schedule time.

Statistical channel options cannot be used in Alarms. The statistical data must first be generated in a Triggered Schedule/ Statistical Sub Schedule, and the data assigned to a Channel Variable (nCV) which then be tested in an Alarm.

Average

AV ñ Returns the average reading for the period, which is the sum of all the channel readings divided by the number of readings.

Standard Deviation

SD ñ Returns the standard deviation of the readings for the period, which is a measure of the variability of the data about the average. The population size used in the standard deviation calculation is (n-1).

Minimum & Maximum 

MN & MX ñ Returns the minimum and the maximum readings for the period, which are a measure of the range of the data about the average.

Date & Time of Minimum & Maximum 

DMN, DMX, TMN, TMX ñ These channel options return the date and the time at which the minimum and maximum values occurred. Any combination of these channel options can be used to return data as required.

Integration

INT ñ Returns the integral of the data for the period. The calculation uses a trapezoidal approximation.

The integral is calculated with respect to the time period in seconds. Other time bases can be used by applying appropriately defined polynomials.

Histogram

Hx:y:n..mCV – Returns a histogram (statistical frequency distribution) of the channel data for a period.

The range of the histogram classes is set by x and y, and the number of classes is set by the number of channel variables between n..m. The class intervals are calculated by the dataTaker for these ranges.

The histogram is produced by counting the number of readings that lie within each class. The class frequency results are placed in the sequentially numbered channel variables.

The histogram is described in detail in Section III - Statistical Sub Schedule.

Examples

Using DeTransfer, the following channel options for example

3TK(AV)(MN)(TMN)(MX)(TMX)

commands the dataTaker to return the average temperature, the minimum temperature and time of the minimum temperature , and the maximum temperature and the time of maximum temperature, for a Type K thermocouple connected to channel 3.

3PT385(INT)

commands the dataTaker to return the integral temperature (heat sum) in degree.seconds measured by an RTD (PT385) connected to channel 3.

Using DeLogger, these channel options are available on the Statistical tab of the Channel Properties dialog in the Program Builder.

 

Options for Channel Variables

Channel Variables are floating point memory registers, that are used to temporarily store data for use elsewhere in the application (See Section III - Channel Variables and Calculations).

The current reading for any channel can be assigned to a Channel Variable by including the Channel Variable as a channel option. The data can be assigned to Channel Variables in a number of ways.

Assign

=nCV ñ Assign the present channel reading to the Channel Variable, overwriting any previous value.

Add

+=nCV ñ Add the present channel reading to the current contents of the Channel Variable.

Subtract

ñ=nCV ñ Subtract the present channel reading from the current contents of the Channel Variable.

Multiply 

*=nCV ñ Multiply the current contents of the Channel Variable by the channel reading.

Divide 

/=nCV ñ Divide the current contents of the Channel Variable by the channel reading.

Examples

Using DeTransfer, the following channel options for example

1TK(=3CV)

commands the dataTaker to assign the reading for a thermocouple type K connected to channel 1 to Channel Variable 3.

2C(R,+=9CV)

commands the dataTaker to read counter channel 2, reset the counter when it is read, and add the value to Channel Variable 9.

Using DeLogger, the channel variable options are available on the CV tab of the Channel Properties dialog in the Program Builder.

 

Options for Output Data Format

The dataTaker can format the data returned to the computer, and the data displayed on the LCD display, in a number of ways.

The following channel options allow each channel to be tailored to a custom data format for its destination. These channel options are described in detail in Section III - Format of Returned Data.

Fixed Floating Point

FFn ñ Data is returned and displayed for the channel in floating point format with n decimal places.

Fixed Exponential digits

FEn ñ Data is returned and displayed for the channel in exponential format with n significant digits in the mantissa.

Fixed Mixed output

FMn ñ Data is returned and displayed for the channel in floating point format with n decimal places if between 10-4 and 10+n , otherwise in exponential format with n significant digits in the mantissa.

Channel identification Text

"text" ñ A unique channel name of up to 16 characters which replaces the default channel number and type which is normally returned and displayed.

No Return

NR ñ Data from the channel is not to be returned to the host, but can be logged and displayed.

No Log

NL ñ Data from the channel is not to be logged, but can be returned to the host and displayed.

No Display

ND ñ Data from the channel is not to be displayed, but can be returned to the host and logged.

Intermediate or Working Channel

W ñ Data from the channel is not to be returned to the host, logged, or displayed. This channel option is used when performing intermediate or working calculations, for which the data is only used internally.

Bar Graph

BGx:y ñ When a display is fitted to the dataTaker, this channel option allows for data to be displayed in a bar graph format on the LCD. The bar graph channel option is described in Section III - Keypad and Display.

Examples

Using DeTransfer, the following channel options for example

1TK("Boiler Temp.",FF1,NL)

commands the dataTaker to read a thermocouple type K connected to analog channel 1, and to return the data named as 'Boiler Temp' in the Floating Point format to 1 decimal place. This data is not logged into memory.

Using DeLogger, the channel label is defined in the Channel Label dialog, and the data format and data use options are defined in the Channel Properties dialog

 

Page Content


Home

Title and Waranty

Go to: Section 2 | Section 3

Section 1


Construction of the dataTaker 50

Construction of the dataTaker 500 600

Construction of the CEM

Getting Started

 

Section 2


Interfacing

Powering the dataTaker

Powering Sensors from the dataTaker

The Serial Interfaces

The RS232 COMMS Serial Interface

The NETWORK Interface

Analog Process

Connect Analog

Analog Chns

Measuring Low Level Voltages

Measuring High Level Voltages

Measuring Currents

Measuring 4-20mA Current Loops

Measuring Resistance

Measuring Frequency and Period

Measuring Analog Logic State

Measuring Temperature

Measuring Temperature with Thermocouples

Measuring Temperature with RTDs

Measuring Temperature with IC Temperature Sensors

Measuring Temperature with Thermistors

Measuring Bridges and Strain Gauges

Measuring Vibrating Wire Strain Gauges

The Digital Input Channels

Monitoring Digital State

The Low Speed Counters

The Phase Encoder Counter

The High Speed Counters

The Digital Output Channels

The Channel Expansion Module

Installing The Panel Mount Display

 

Section 3


Programming the dataTaker

Communication Protocols and Commands

Entering Commands and Programs

Format of Returned Data

Specifying Channels

The Analog Input Channels

The Digital Input Channels

The Counter Channels

The Digital Output Channels

The Real Time Clock

The Internal Channels

Channel Options

Schedules

Alarms

Scaling Data - Polynomials, Spans and Functions

CVs Calcs and Histogram

Logging Data to Memory

Programming from Memory Cards

STATUS RESET TEST

Switches and Parameters

Networking

Writing Programs

Keypad and Display

Error Mess Text

Appendix A - ASCII

Appendix B - ADC Timing