March 14th, 2012
A new range of water-approved submersible level transmitters is now available from instrumentation specialist Impress Sensors & Systems Ltd.
The new IWSL range of WRAS-approved submersible level transmitters is suitable for continuous submersion in water, for a wide range of level measurement applications in reservoirs and drinking water storage tanks, but also for use in rivers, boreholes, aquifers, environmental monitoring and V-notch weir flow measurements.
IMSL WRAS Approved submersible level transmitter
Manufactured in the UK by Impress Sensors, the IWSL sensors use a piezoresistive media-isolated, silicon sensing technology and a stainless steel diaphragm, which provide excellent stability, repeatability and resolution. The sensor housing is 316L stainless steel, making it ideal for reliable, repeatable hydrostatic level measurement. The sensors are available in nominal pressure ranges from 1mWG to 100mWG.
When installing a product that will carry, receive or be submersed in water from the public mains water supply in the UK, it is a criminal offence if that device does not comply with the Water Supply Regulations or Scottish Byelaws. The Water Regulations Advisory Scheme (WRAS) requires that these devices should not cause waste, misuse, undue consumption or contamination of the water supply and must be of an appropriate quality and standard. WRAS approval is the best way to demonstrate compliance as it is granted directly by representatives of the water suppliers and is therefore accepted by every water supplier in the UK.
All IWSL sensors are WRAS-approved with a single WRAS approval number and are temperature-compensated, calibrated and supplied with a traceable serial number and calibration certificate. Operating (media) temperatures are from -20 deg C to +60 deg C in non-freezing media. Cable material is PUR, with elastomeric (EPDM) O-ring seals that are carefully selected for compliance with WRAS.
Sam Drury, Sales & Marketing Director at Impress Sensors & Systems comments: “The electronics on the IWSL incorporate a microprocessor-based amplifier, which means no adjusting pots are required, which in turn means the electronics are very stable. The IWSL can also be custom engineered for specific applications, including various output options, accuracy levels and pressure ranges. The sensor is also suitable for battery operation when output options of millivolt or SDI-12 are selected.”
Impress Sensors will be exhibiting at IWEX 2012 (International Water & Effluent Exhibition) at the NEC from 22-24 May 2012 (stand E48), and at the WWEM (Water, Wastewater & Environmental Monitoring) exhibition, from 7-8 November 2012 at the Telford International Centre (stand 58).
For more information on the IWSL range of water-approved submersible level transmitters, please visit www.impress-sensors.co.uk or call the sales team on 0118 981 7980.
March 3rd, 2012
A new range of submersible dual output level and temperature transmitters is now available from instrumentation specialist Impress Sensors & Systems Ltd.
Manufactured in the UK by Impress Sensors, the new transmitters are suitable for continuous submersion in liquids such as water, oils and fuels. The sensors are available in ceramic (IMCTL) or silicon (IMSTL). All sensors provide dual independent, 2-wire, 4-20mA outputs: one for level and one for temperature, with no signal loss over long cable lengths. The sensors offer nominal pressure ranges from 10mWG to 100mWG (ceramic) and 0.5mWG to 100mWG (silicon).
Dual output Submersible level transmitter with integrated temperature sensor
The temperature sensor is based on a platinum resistance thermometer with Class ‘B’ accuracy (other accuracy classes are also available). The sensor housing is either 316L stainless steel, high grade Duplex stainless steel or a Marine bronze option for the IMCTL, making the transmitters ideal for hydrostatic level measurement, where temperature is also a critical factor in measurements.
All sensors are temperature-compensated and calibrated and supplied with a traceable serial number and calibration certificate. Operating (media) temperatures are from -20 deg C to +60 deg C in non-freezing media. Cable material is PUR, with PVC, FEP or TPE as options.
The IMSTL is the higher accuracy version and uses the latest piezoresistive media-isolated silicon sensing technology and a stainless steel diaphragm. This provides excellent stability, repeatability and resolution, particularly for high accuracy level and temperature measurement (including V-notch weir flow measurements) in rivers, canals, reservoirs, boreholes and aquifers.
The IMCTL is also designed for submersion in liquids such as water, oil and fuels. This device uses a ceramic sensor for level measurements, which provides excellent corrosion resistance, particularly where the media may be aggressive. Applications include level and temperature measurements in storage tanks, rivers, boreholes and aquifers, as well as environmental monitoring in estuaries and seawater applications (when used with the marine bronze housing).
Sam Drury, Sales & Marketing Director at Impress Sensors & Systems comments: “Because we manufacture the IMSTL and IMCTL sensors in-house, we can offer different versions of the sensors tailored for specific customer applications. For example, we can provide different level and temperature ranges, sensors for drinking water applications or WRAS-approved versions with special cable materials.”
For more information on the IMSTL and IMCTL sensors, please visit the website at www.impress-sensors.co.uk or call the sales team on 0118 981 7980.
February 25th, 2012
We are pleased to inform you of some new features included in the latest firmware release 2.40.2 for the CMC-99 and CMC-141 Multicon devices.
The phasor charts allow for intuitive presentation of phase/amplitude between signals. Each arrow is controlled by 2 Log channels – one for phase, and the second one for amplitude. Thanks to such solution a singular group can be easily used to show parameters of three-phase supply grid.
Background Colours can easily be changed
In the pictures below it is shown that Logical channels can be displayed in other colours than default. This functionality is intended to indicate different states of a channel. The colour of the channel background is controlled by another channel, this gives a unique opportunity to use this feature for many purposes. More interestingly each background may be configured to be shown in a permanent or a blinking mode. Settings of the colour and controlling channel can be easily done by additional menus in the configuration setup.
We have extended the time scale of the time charts – the new range is 19sec up to 24h. In fact this tool was improved in order not to allow analysis of historical data, but to give an opportunity to see last N minutes (or hours) of the signal on the touch screen, without using the DAQ Manager PC Software.
Quick exit from Menu
And the last, but also very useful feature which has just been introduced is a possibility to exit the configuration menu without saving it. This saves a lot of time during configuration process. If user exits the configuration menu (and has changed something), then appropriative message is displayed, and after that a special “tool” icon is visible on the upper bar (see picture below). This increases the, already quick, programming time!
For more information on the CMC-99 and CMC-141 Multicon devices please visit the appropriate page on the website here: http://www.impress-sensors.co.uk/cmc-99-multichannel-pid-controller.htm
February 21st, 2012
Impress Sensors also offer a full range of pressure transmitters, screw-in transmitters, submersible probes and level control switches, all with SIL2 (Safety Integrity Level 2) approval for hazardous environments.
The product range is is targeted at safety and hazardous area applications, including process manufacturers, chemicals, oil and gas, nuclear and Atomic Weapons establishments. The devices are also suitable for medical device applications.
The process industry demands the highest degree of safety and reliability these days. The current Safety Integrity Level (SIL) international safety standard provides suppliers and users with a common framework on which to design products and systems for safety related applications. The standard also provides a more scientific, numerical approach to specifying and designing safety systems, enabling the nature of the risk to be quantified.
SIL means risk reduction to a tolerable level. The required safety level of a process plant is classified in accordance with the international IEC 61 511 standard and depends on the risk constituted by a plant. The IEC 61 508 standard describes the requirements of electrical, electronic and programmable electronic devices used in such plants. Both standards subdivide plants and devices into 4 safety levels, from SIL1 for low risks, to SIL4 for very high risks. The allocation to these safety levels is based on the use of a risk graph and depends on:
• Extent of possible damage
• Frequency of persons present in hazardous areas
• Possibility of damage prevention
• Probability of an unwanted event occurring
The standards also describe the type of risk assessment and procedures for integrating certain safety functions into sensors and plants. Generally, the significant hazards for equipment and any associated control system have to be identified by the specifiers or developers via a hazard analysis. The analysis identifies whether functional safety is necessary to ensure adequate protection against each significant hazard.
Examples within safety related systems for mechanical engineering include auxiliary disconnected systems; fire detector and gas warning systems; monitoring of turbines; safety interlock and auxiliary disconnected systems for machines; devices for medical applications; and remote monitoring based on network, handling and programming of procedural constructions.
For more information on Impress Sensors’ range of SIL2-certified pressure, temperature and level control switches, contact the sales department at Impress Sensors & Systems Ltd on 0118 981 7980 or visit the website at http://www.impress-sensors.co.uk/sil-products.htm
February 20th, 2012
In the latest firmware updates for the CMC-99 and CMC-141 Multicon devices we the following changes and additions to announce:
- Historical charts time adjusted to now be selectable from 19sec up to 24 hours
- Realtime progress display while saving a configuration
- Edge triggering now more efficient on the profile/timer setting of a channel
- 3 levels of channel background now selectable
- channel backgrounds can be driven from other channels
- Phasor (polar chart) display mode added
- Limit control of the exponential function on the PID control
- Modbus status update for the output registers
- Function 6 of modbus protocol support added
- Manual can be downloaded from the device itself
As you can see quite a few additions in this release. Please contact sales if you would like to get the latest copy send on a Impress Sensors 2GB memory stick: http://www.impress-sensors.co.uk/contact-details.htm
February 13th, 2012
In the previous articles we presented the device design and options of presentation of results and operation using the touch panel. To have a full picture of huge potential of MultiCon, now we will focus on processing measurement data, control functions and possibilities of cooperation in network systems.
The distinguishing feature of MultiCon is its capability of simultaneous implementation of tasks related to measurements, processing, control and recording of data. To make this possible, the designers have used the concept of “logical channels” which are virtual bridge between physical inputs/outputs and control and visualization processes. An expanded configuration menu of logical channels allows for a very precise configuration. It will not suffice to mention the names, units of measure, precision of displayed data or ranges of indicators and graphs. The designers provided for easy rescaling of collected data, as well as filtering or data hold controlled by another channel.
In the MultiCon devices, it is the user who decides how to use the available logical channels. The parameter which allows to select the channel function is the “operation mode”. It can be set so that the logical channel: represents the data from physical inputs and outputs; processes the data from other logical channels using the mathematical and logical functions; generates constant values (set points) or sequence diagrams (profiles); works in the PID controller mode; constitutes a virtual function key. Relationships between channels (including mathematical operations on the values) can be set directly in the device and it is not necessary to know any programming language. As the essence of any data processing is mathematical operations in the device, many standard functions have been provided to build complex algorithms.
In addition to the basic mathematical functions, such as addition, subtraction, multiplication and division, the device allows, amongst others, to use trigonometric functions, calculate the mean or maximum or minimum value from any number of channels, as well as logical functions or comparison and election. The source of data in mathematical functions can be of course other logical channels and constant values set in the menu. One of the most important functions of MultiCon is a controlled configuration menu of built-in outputs (e.g. relays) which allows to use them directly as so-called two-position controllers.
Free combination between inputs and outputs allows to create easily multi-channel controllers operating totally independently. In addition, the concept of logical channels provides an opportunity of making many outputs (including outputs of different types) dependent on a single input channel, and introduction of mathematical operations significantly expands the control options.
In addition to ordinary ON/OFF control using binary signals, MultiCon allows PID control using built-in and external analogue outputs or SSR outputs in the PWW mode. Each of 60 logical channels can be set in the PD, PI, PID controller modes with an independent set point, input and output. The user can choose from 8 sets of PID control parameters (available in the “Controllers” submenu) each of which can be assigned to many logical channels operating in the controller mode. This is a perfect solution when many similar processes need to be controlled. The MultiCon can work then as a unique multi-channel PID controller.
For more information on the CMC-99 and CMC-141 MultiCon devices please visit the website page for more infaormtation: http://www.impress-sensors.co.uk/cmc-99-multichannel-pid-controller.htm
February 13th, 2012
In the previous article we presented a concept and features of the MultiCon series devices and the outline of their possibilities obtained as a result of well developed software and a modular design. This part will describe other advantages, including simple operation and configuration using a TFT with a touch screen, a thing well know from such devices as smartphones or tablets.
Easy change of data presentation and displayed channels is a feature which might be useful in many cases. MultiCon offers numerous possibilities in this area – the basic function is bringing up the contextual menu by touching the display briefly. Then, a set of buttons appears on the bottom of the screen to switch between the display modes, channel groups or to enter the menu.
The “MODE” buttons allow a quick selection of data presentation method on the screen. Depending on whether we need a detailed information on the signal value, quick insight into the signal level, or parameter trend over time, the data can be presented.
In the first four modes, the panels present in a clear manner the name and the unit of measure which are specified and entered by the user, its graphical or numerical representation, and in addition a percent value in relation to a set level. The last mode allows to present as numbers up to 30 channels on one screen. This mode is particularly comfortable in MultiCon-141 equipped with a large 5.7” display.
The time graph data presentation mode is useful for recording operation. Depending on the configuration, the graph background can be black and the graph itself can be set as horizontal or vertical to maintain conformity with traditional paper recorders. The user can also set the line thickness. For the sake of clarity of results, the measurement channels are assigned to groups. The “GROUP” buttons are used to select the group which will be displayed. A mimic board view with 30 channels from groups from 1 to 5. Using the “GROUP” buttons will change the range of displayed channels; this also applies to all other data display modes.
MultiCon CMC-99 has 10 groups, and MultiCon CMC-141 has 15. A single group can contain maximum 6 channels, but the channel assignment to groups is not restricted, and the same channel can be displayed in many groups, providing the user with full flexibility to group various indications (e.g. one room, the same equipment, groups of measurements of the same type, etc.). Selecting the number of channels assigned to a group, we can obtain different sizes of various indicators.
The MultiCon series device equipped with the ACM (advanced communications module) allow also a very easy remote monitoring of measurement results usinf a web browser, as well as a very attractive graphical presentation in the form of built-in or user-created websites. Along witht he device, the manufacturer supplies a set of built-in Java applets which using the modbus TCP protocol provide the programmers with an easy mechanism to retrieve data from the device, as well as ready-to-use formats of data presentation on the computer screen.
In order to facilitate the use of their own websites by the users who do not know HTML, we have prepared a few standard examples which are distributed with the free DAQ manager software used to manage the data recorded.
It is necessary to mention one more data display mode – “Setpoint” – although it is more related to the channel operation mode than the presentation of the results. Touching the screen in the field of such configured channel, the user can in no time at all change a fixed value assigned to the channel (e.g. a threashold in the controller). In addition, this mode can be mixed with binary data presentation as described above which allows an easy definition of function keys on the screen. The other interesting feature of the “Setpoint” mode is access to the settings. Depending on the needs, the admin can configure a channel so that the changes are made only by authorised users or any operator, also the one who does not know the password.
As a piece of interesting information, let us here present a “trick”. A quick access to group settings or settings of channels in a group. Instead of entering the menu and selecting the channel from the list, you can just touch and hold the screen in the area of the channel that interests you and you immediately enter the editing of this channels parameters. Operation of the group is similar: press and hold the top bar on the group name and you enter the relevant submenu.
For more information in the products or a copy of the manual and software please visit the website: http://goo.gl/1I0ox
February 8th, 2011
Level switches are helpful in detecting powder or liquid levels. They can also be used to determine interfaces between liquids. The level measurement is often indicated through the electrical switching action. Point level switches are also available for measuring liquid level in a container. The switching mechanism of level switches is crucial for all continuous level measurement switches.
To offer a stepped version of constant level, multiple switches can also be integrated. The level switches can either be used as control switches or as an alarm device. They can also be used for sending signals to a valve actuator or to turn something off or on. Level switches provide a switched output which can be solid state or electromechanical, either normally closed or normally open.
Typical options for throws and poles are also available with level switches. While some switches have one or two throws or one or two poles, some manufacturers do offer customised level switches for special applications. When selecting level switches, the measuring range is an important specification to consider. The rating for voltage and current is also an important consideration when looking for level switches.
Mounting and technology used in level switches
Depending on specific application needs, level switches can be mounted in different ways. Level switches can be mounted on the side, bottom or on the top of the container. Technologies used for level measurement include RF or capacitive admittance, air bubbler technology, electrical resistivity or conductivity, magnetic or mechanical floats, differential pressure, microwave or radar, pressure membrane, optical units, tuning fork or vibration, sonic or ultrasonic, rotation paddle and radio frequency technology.
January 24th, 2011
Signal conditioners are quite helpful in offering amplification, converting and filtering. They are also required in other processes to make the sensor outputs readable by computer boards. Signal conditioners are also used for data acquisition. Using these devices sensor signals are filtered and normalised to levels that are suitable for analogue-to-digital conversion.
When looking for signal conditioners, there are some important parameters you need to look for. These include –
• Signal conditioning type
• Device specifications
• Form factor
• Sensor inputs
• Signal inputs
• Specialised inputs
• User interface
Application, storage and memory, software, filter and network specifications, environmental parameters and amplifier specifications are some other things to look for prior to buying signal conditioners.
What you must know about signal conditioners
Some common form factors of signal conditioners include; board or IC mount, chassis or panel mount, circuit board, slot system or modular bay, stand-alone, DIN rail and rack mount. The digital I/O channels, differential analogue input channels and accuracy are some important device specifications to consider when choosing signal conditioners.
Differential channels make use of the difference between two signals as the input while filtering out the common mode. Some signal conditioners use a combination of 2 single-ended inputs as differential inputs.
On the other hand, discrete or digital channels are used for low-level off-on signals. These channels are used in different applications like user interface, control or communication. The accuracy level of these devices depends on hysteresis, linearity of signal conditioning and temperature considerations.
January 21st, 2011
Data recorders and data loggers are devices that receive digital data from sensors. They are commonly used for storing data for storing data onto a host PC. These devices can also have real-time features like alarms and monitors.
When looking for data recorders and data loggers, you must consider some important specifications. These specifications include digital I/O channels, accuracy, resolution, differential analogue input channels and sampling frequency.
Sampling frequency of data loggers and recorders is the frequency of analogue signal sampling that is then converted into a digital value. Similarly, resolution is the degree of fineness that represents the analogue value.
A 10-bit number usually contains 1024, or 210 increments. Thus, a 0-10V signal can be resolved to approximately 0.01V increments. On the other hand, a 12-bit representation can be in 212 increments (4096) or division of 0.0024V for the equivalent signal.
Some important things you must know
Common form factor of data recorders and data loggers include a modular bay or slot system, board or IC mount, chassis or panel mount, circuit board etc. Applications include industrial or general lab use, marine, vehicular, aerospace, environmental, metrology or weather, biomedical or medical and geotechnical or seismic.
Signal inputs available for data recorders and data loggers include AC current, DC voltage, AC voltage, charge, frequency and DC current. Sensor inputs can include RTD, thermistor, accelerometer, bridge or strain gauge, thermocouple and RVDT or LVDT. Specialised inputs can include tachometer or counter, switch or relay, clock or timer and encoder. Excitation and transducers are also important to consider while looking for data acquisition.