Moravian instruments, Inc., source: https://www.mii.cz/art?id=176&lang=409, printed: 18.05.2024 13:02:18

Main pageProductsDataLab industrial input/output systemDataLab - Industrial input/output devices

I/O modules for DataLab IO
 Industrial input/output devices DataLab IO have modular design. It is possible to connect four modules to DataLab IO4, two modules to DataLab IO2 and one module to DataLab IO1. The basic DataLab IO device handles USB traffic and provides the power, while I/O modules perform the specified I/O operations.

The DataLab IO units are not sold in some predefined configurations. Every customer can specify which modules should be included into the device. Modules can be digital or analog and input or output. There can be several kinds of one module class—for instance there are two kinds of digital output module, one with open-collector transistors, another with relays.

All I/O modules are universal—they can be used in any slot of any DataLab IO device—DataLab IO4, DataLab IO2 and DataLab IO1.

The DataLab IO with four I/O modules

The DataLab IO4 with four I/O modules

The DataLab IO with two I/O modules

The DataLab IO2 with two I/O modules

The DataLab IO with one I/O module

The DataLab IO1 with one I/O module

Analog input module AI3

This module is designed for measuring of analog voltage or current values in the standard industrial ranges with 16-bit resolution. Inputs are bipolar and electrically isolated.

Range Voltage input Current input
0 input inactive input inactive
1 +/-10 V N/A
2 +/-5 V N/A
3 +/-2 V +/-20 mA
4 +/-1 V +/-10 mA
5 +/-0.5 V +/-5 mA
6 +/-0.2 V +/-2 mA
7 +/-0.1 V +/-1 mA
8 input inactive input inactive
9 0..10 V N/A
10 0..5 V N/A
11 0..2 V 0..20 mA
12 0..1 V 0..10 mA
13 0..0.5 V 0..5 mA
14 0..0.2 V 0..2 mA
15 0..0.1 V 0..1 mA

Input ranges of AI3 analog input module

The default input range is +/-10 V.

There is a jumper on the module PCB associated with every input channel. Closing the jumper causes a precision 100 Ω resistor is inserted into the input, which changes voltage input into the current one.

Input ranges can be defined for every input channel independently by the application program. But the voltage or current mode is selected by jumper on the PCB and this cannot be performed on application runtime.

The AI3 module allows not only input range setting for individual inputs, but also allows switching each input off. Skipping of particular input speeds up the sampling frequency of remaining inputs.

The module is able to sample data at frequency 50 Hz (50 samples per second) on one channel. If all 8 channels are measured, the sampling speed is 6.25 Hz. If it is for instance necessary to sample data 10× per second, only 5 channels can be turned on, remaining 3 channels must be turned off.

It is not necessary to wait for the digital filter to settle down when only one channel is measured and the input multiplexer is not switched. The data sampling frequency is then 200 Hz. But keep on mind that the A/D converter is not able to pass the step over the full input range to its output at this speed. If the input voltage changes e.g. from -10 V to +10 V, the converter needs 4 cycles to propagate the step to the output. So the sampling frequency is again 50 Hz.

Isolated 16-bit analog input module

Isolated 16-bit analog input module

Analog output module AO1

Analog output module provides 8 voltage analog outputs with the range 0 to +10 V. D/A converter has 12 bit resolution. Each D/A converter count equals to 2.5 mV output voltage change.

Because 12 bit resolution provides 4096 counts, 2.5 mV per count equals 10.24 V. If the output must not exceed 10 V, the software must not write value greater than 4000 to the output channel.

When the driver is configured to use physical units (volts), such problem does not occur. For instance writing 10 to the output channel means the 10 V (with the uncertainty about 0.1 % caused by used components) appears on the output pins.

First four of eight outputs can be configured as current outputs with range from 0 to 20 mA using jumpers on the module PCB. Due to the high resolution of the DAC the 4 to 20 mA range is implemented by software limitation of 0 to 20 mA range.

The current source generates 20 mA when the DAC value is 3846 counts (with the uncertainty about 0.1 % caused by used components). Configuring the driver to use physical units (amperes) eliminates the necessity to recalculate written values. For instance writing 0.02 to the output channel means the current source will generate 20 mA current.

Isolated 12-bit analog output module

Isolated 12-bit analog output module

Combined analog input and digital input/output module AD1

The AD1 module provides four differential analog inputs, functionally equivalent to the AI3 module.

Range Voltage input Current input
0 input inactive input inactive
1 +/-10 V N/A
2 +/-5 V N/A
3 +/-2 V +/-20 mA
4 +/-1 V +/-10 mA
5 +/-0.5 V +/-5 mA
6 +/-0.2 V +/-2 mA
7 +/-0.1 V +/-1 mA
8 input inactive input inactive
9 0..10 V N/A
10 0..5 V N/A
11 0..2 V 0..20 mA
12 0..1 V 0..10 mA
13 0..0.5 V 0..5 mA
14 0..0.2 V 0..2 mA
15 0..0.1 V 0..1 mA

Input ranges of AD1 analog inputs

The default input range is +/-10 V.

There is a jumper on the module PCB associated with every input channel. Closing the jumper causes a precision 100 Ω resistor is inserted into the input, which changes voltage input into the current one.

Input ranges can be defined for every input channel independently by the application program. But the voltage or current mode is selected by jumper on the PCB and this cannot be performed on application runtime.

The AD1 module allows not only input range setting for individual inputs, but also allows switching each input off. Skipping of particular input speeds up the sampling frequency of remaining inputs.

The module is able to sample data at frequency 50 Hz (50 samples per second) on one channel. If all 8 channels are measured, the sampling speed is 12.5 Hz.

It is not necessary to wait for the digital filter to settle down when only one channel is measured and the input multiplexer is not switched. The data sampling frequency is then 200 Hz. But keep on mind that the A/D converter is not able to pass the step over the full input range to its output at this speed. If the input voltage changes e.g. from -10 V to +10 V, the converter needs 4 cycles to propagate the step to the output. So the sampling frequency is again 50 Hz.

The AD1 module also contains four digital input/output channels. The module contains a set of jumpers on the PCB, which allow choosing of channel direction (input or output) and channel input resistance (low voltage or high voltage) for the input direction. Every channel can be switched independently so the actual number of inputs and outputs is chosen by the user.

Digital inputs are bipolar and they can be read in two modes—DC and AC. Reading the channel in DC mode returns the actual logical value according to the voltage present on the terminal connector pins. AC inputs are evaluated the same way like in the case of digital input modules.

Combined analog input and digital input/output module

Combined analog input and digital input/output module

Combined analog input/output and digital input/output module AD2

The AD2 module contains 4 analog input channels, 2 analog output channels and 2 digital channels, which can be configured either for input or output.

The analog input part of the AD2 module is identical to the AD1 module. Refer to its description for input ranges, sampling frequencies etc.

Two analog output channels of AD2 use 8-bit D/A converter. Bout analog outputs can be independently set as voltage or current using the PCB jumpers. Voltage range is 0 to +10 V, current range is 0 to 10 mA. Maximum sampling rate 200 Hz is limited by the communication speed between the DataLab IO device and the host computer.

The AD2 module also contains two digital input/output channels. The module contains a set of jumpers on the PCB, which allow choosing of channel direction (input or output) and channel input resistance (low voltage or high voltage) for the input direction. Every channel can be switched independently so the actual number of inputs and outputs is chosen by the user.

Digital inputs are bipolar and they can be read in two modes—DC and AC. Reading the channel in DC mode returns the actual logical value according to the voltage present on the terminal connector pins. AC inputs are evaluated the same way like in the case of digital input modules.

Combined analog input/output and digital input/output module

Combined analog input/output and digital input/output module

Analog input/output module AIO1

The AIO1 module combines two high-precision modules AI3 and AO1. It contains 4 16-bit analog inputs and 4 12-bit analog outputs.

The analog input part of the AIO1 module is identical to the AD1 module (which is in fact just “one half” of the 8 channels AI3 analog input module). Refer to its description for input ranges, sampling frequencies etc.

Analog output part is similarly identical to the “one half” of the AO1 module. Refer to its description for output modes, ranges, sampling frequencies etc. The only difference is the AIO1 module contains only 4 analog outputs, so all 4 outputs can be used both in voltage mode (with range from 0 to 10 V) and in current mode (with range from 0 to 20 mA).

Analog input/output module

Analog input/output module

Digital input module DI1

Module contains 8 insulated digital inputs. The module is available in two variants for two input signal levels. The DI1L variant is designed for 0 to 18 V input range, DI1H variant is designed for 0 to 35 V input range. Voltage levels for DC signals for logical true and false are:

  • DI1L parameters

    • Input resistance is 1 000 Ω

    • 0 to 1 V is evaluated as false.

    • 3 V to 18 V is evaluated as true.

    • The logical value is undefined for input voltages from 1 V to 3 V.

  • DI1H parameters

    • Input resistance is 4 700 Ω

    • 0 to 3 V is evaluated as false.

    • 8 V to 35 V is evaluated as true.

    • The logical value is undefined for input voltages from 3 V to 8 V.

Timing limits for AC signals are:

  • 50 or 60 Hz AC signal is evaluated as logical true.

  • Logical false is read if the input signal does not change for at last 20 ms.

Maximum sampling rate for DC signals is limited by USB communication between DataLab IO and host PC. The communication overhead is approx. 2ms1, which results to maximum frequency around 500 Hz. This frequency depends on used computer, its USB interface and also on USB load factor—if the unit is connected through USB hub together wit another USB devices (e.g. USB disk drive), the maximum sampling rate can significantly decrease. On the other side, the system response does not depend on the number of communicated channels of one module—the response time is the same if the application manipulates only one or all eight channels.

Optical input decoupling is independent on input signal polarity, which means the module can read also AC inputs. Evaluation rules of logical values differ from DC mode, they are thoroughly described in the  DataLab IO driver description.

Optically insulated digital input module

Optically insulated digital input module

Single-ended digital input module DI2

This module is a functional equivalent of the digital input module, including sampling rates, voltage levels etc. The only difference is the common ground for all 8 inputs is wired to one terminal connector. This module can contain insulated DC-DC converter, which enables sampling of voltage-less inputs (simple switches).

Optically insulated common-ground digital input module with power supply

Optically insulated common-ground digital input module with power supply

Digital counter input module CNT1

The module contains 4 isolated digital counters.

  • Counter range is 24-bit (0 to 16,777,215)

  • 25 kHz maximal input frequency with 1:1 duty cycle

  • Two counters with alarm output signaling exceeding of the predefined value

  • Two counters with external counting enable (gate) signal

  • Counter modes (counting enable, logical signal levels etc.) are defined by software

Limit frequency ensuring error-free counting if 25 kHz when the signal has 1:1 duty cycle. If the duty cycle is not 1:1, limiting frequency is lower, because the input signal must stay in each logical state for at last 20 μs. For instance the limiting frequency is 10 kHz for the 1:4 duty cycle.

Digital counter module

Digital counter module

Incremental counter module CNT2

The module contains 1 incremental counter.

  • The module contains quadrature modulation decoder

  • Other counting modes include up/down and step/direction counting

  • Counter range is 32-bit (-2,147,483,648 to 2,147,483,647)

  • 25 kHz maximal input frequency with 1:1 duty cycle

  • Two logical outputs signaling underflow and overflow of defined values

  • Logical input for counter value preset

  • Logical input for counter value capture

Limit frequency ensuring error-free counting if 25 kHz when the signal has 1:1 duty cycle. If the duty cycle is not 1:1, limiting frequency is lower, because the input signal must stay in each logical state for at last 20 μs. For instance the limiting frequency is 10 kHz for the 1:4 duty cycle.

Relay digital output module DO1

Module contains 8 relays with limit values:

  • Maximal voltage 230 V AC, 3 A.

  • Maximal voltage 30 V DC, 3 A.

Estimated relay life (mechanical) is 100 000 switches and life (electrical) is 20 000 000 switches. Maximal frequency depends on the relays and exceeds 50 Hz.

Relay digital output module

Relay digital output module

Open-collector digital output module DO2

Module contains 8 insulated digital outputs. Limit levels are:

  • Maximal voltage 60 V.

  • Maximal current for one output 250 mA.

Sampling frequency is limited as in the case of digital input module.

Optically insulated open-collector digital output module

Optically insulated open-collector digital output module

Single-ended open-collector digital output module DO3

This module contains 8 digital outputs witch open-collector transistors. All outputs have common ground. Limit levels are:

  • Maximal voltage 50 V DC.

  • Maximal current 800 mA (all outputs together) or 500 mA (single output).

Sampling frequency is limited as in the case of digital input module.

Single-ended open-collector digital output module

Single-ended open-collector digital output module


1Measured on the Athlon XP 2000+ PC with VIA KT 400 chipset and Windows XP Professional