Thursday, March 14, 2019

Process Weighing Systems Overview

High-accuracy, batch-processing tank
fully supported by KIS Weigh Modules.
In its simplest form, a weigh system consists of a vessel whose contents are to be monitored, load cells or weigh modules that generate a signal proportional to the vessel weight, and an electronic device to power, amplify, interpret and display the signal. However, the accuracy of such a system, while obviously a function of the instrumentation, is also dependent upon the vessel design (reactor, batch tank, inventory silo, etc.), support structure, piping attachments, lateral restraint system, vessel environment (temperature, traffic, nearby equipment), and proper selection of transducer accessories. In short, weigh system accuracy is inexorably tied to the degree of attention given to the mechanical details and vessel functionality.

High accuracy, process weighing systems exhibit system errors under 0.05% for buy-and-sell to 0.25%. Precision load cells or weigh modules with full temperature compensation must be used. To achieve this, the following mechanical requirements are imposed:
  • The weigh vessel must be fully supported by load cells/weigh modules. The number of load cells/weigh modules may vary from one (in tension) to eight (in compression). Generally, as the number of load cells de-creases, the vessel wall thickness and support structure stiffness must increase to carry the higher vessel support reactions lest vessel deformation cause calibration errors.
  • Mechanical restrictions from attached piping and lateral restraints should be avoided. Highly flexible piping attachments are recommended.
  • Hot gas or steam-heating schemes which produce variable buoyancy should be avoided. Consult factory for alternate solutions.
  • Low accuracy inventory weighing systems are those with a system error greater than 0.5%. General purpose cells/ modules are satisfactory for these systems. Mechanical considerations are relaxed considerably:
  • The weigh vessel need only be partially supported by load cells/weigh modules, usually one or two on any side or end of the vessel. This, however, requires the contents to be self-leveling and the vessel itself to be without partitions, so that the load fraction carried by the load cells/ modules is unchanging. (Vessels falling into these two categories must be fully supported, independent of the accuracy required.)
  • Modest mechanical restrictions may be tolerated, but nonlinear mechanical hang-ups or frictional interfaces must still be avoided.
Accuracy Versus Repeatability

Low-accuracy, storage silo partially
supported by KIS Weigh Modules.
Do not confuse system accuracy with repeatability! As long as the mechanical error in a given system is linear with deflection and independent of the environment (temperature, traffic, surrounding vessels, etc.), the inherent system repeatability will be greater than its accuracy. For example, BLH Nobel Transducer Indicators typically have an overall accuracy specification of 0.01% of reading, ±1 count (or better), of which repeatability is but a small fraction. BLH Nobel load transducers, meanwhile, typically display a repeatability of 0.01 to 0.02%. Thus, most BLH Nobel systems will be repeatable within 0.03% of full scale, independent of how the system is calibrated. For most batching operations, repeatability is essential, whereas accuracy (actual pounds used) is of secondary importance once the operating parameters have been established. Field calibration, when required, is generally done by electronic simulation. For buy-and-sell installations, where distribution is by weight, calibration and repeatability are essential; field calibration is always performed employing a dead weight method.

Definitions:
  • Accuracy - Ability of the system to perform weighing functions within an acceptable or desirable tolerance; usually stated as a percentage of either full-scale reading, or ±n count(s) referred to the total number of scale divisions.
  • Repeatability - The ability of the system to read the same value when the measured weight is applied repeatedly in the same manner with the same quantity under constant conditions.
Maximum accuracy and repeatability is obtained by placing high accuracy load cells/modules at all support points and connecting them to instrumentation that measures each cell/module individually.

For more information on any process weighing application, contact Arjay Automation. They can be reached by phone at (800) 761-1749, or visit them on the Web at https://arjaynet.com.

Thursday, February 28, 2019

The Yokogawa YS1000 Series Single Loop Controller

YS1700

Now that entire Moore/Siemens 350 family is obsolete, are you considering upgrading to a DCS? 

Are you concerned about the cost and time for a new installation, application development and personnel training?

Is it possible that the new equipment vendor may again leave you stranded with their equipment as their core business is not industrial automation and control?

We have a better solution for you: Yokogawa and its YS1700 PID loop controller. Yokogawa has been providing industrial solutions, as their primary business, for over a century and their YS1700 will keep you off of eBay looking for spare 353 parts.



Friday, February 22, 2019

Consider This Robust and Flexible Multi-point Magnetic Level Switch for your Next Tank Level Application


The NIVELCO NIVOPOINT is a flexible, multi-point magnetic float level switch available with awide variety of floats. The NIVOPOINT magnetic float level switch is an ideal solution for single or multi-point level controlling tasks in non-hazardous or hazardous areas. Plastic coated versions are available, suitable for level detection of aggressive liquids, while ATEX certified versions do an excellent job in explosive medium.

Operating Principle:

NIVOPOINT magnetic float level switches work on the basis of the interaction of the magnet incorporated in the float, and the reed switches within the probe.

The float of the NIVOPOINT level switch moves alongside the probe tube, tracking the level of the measured liquid and activating the reed switches.

NIVOPOINT magnetic float level switches are recommended for the following applications.
  • Multi-point level switching.
  • Controlling pumps and valves.
  • Level detection of practically all liquids, including aggressive ones.
  • Level switching of explosive liquids.
Main features:
  • Level switching without auxiliary power.
  • Up to 5 switching points.
  • The position of the switches can be adjusted.
  • Plus or minus 25 millimeter adjustment possibility of the positioning of the switches.
  • Plastic coated versions for aggressive chemicals.
  • 150 degree Celcius median temperature.
  • Mini version for tight places
  • Wide variety of floats.
  • Ex version
  • IP65 and IP68 protection
For more information on the NIVELCO NIVOPOINT magnetic level switch, contact Arjay Automation by calling (800) 761-1749 or visiting their web site at https://arjaynet.com. 

Tuesday, February 12, 2019

Selecting the Right Gas Detection Solution

Honeywell gas detection
XNX™ Universal Transmitter
Reprinted from https://www.honeywellanalytics.com. Original article by Don Galman. 

There are many gas detection products on the market that might appear to be the same, but a closer inspection of specification, functionality and features reveals major differences in what products can do and the potential value they can offer. Similarly, individual applications are also unique in their respective designs, needs and processes undertaken.

Know your site risks

Before beginning to consider gas detection equipment, a risk assessment needs to be conducted. Any company employing staff has the obligation to conduct risk assessments to identify potential hazards and these can include potential gas, vapor or Oxygen deficiency risks. If gas hazards are identified, gas detection is applicable as a risk reduction method.

Identifying the prime objective

Depending on the processes being undertaken and the gases being detected, remote or off-site alarm notification plus event data logging/reporting may also be required for Health and Safety management records. Another factor impacting on the need for enhanced reporting functions might be regulatory compliance or a condition of insurance.

Ask the right questions

Having identified the primary objective, the suitable equipment is selected by asking a number of key questions. These fall into three broad categories:

• The gases to be detected and where they may come from

• The location and environmental conditions where detection is to take place

• The ease of use for operators and routine servicing personnel

Identify the gases to be detected and where they may come from

The gases to be detected should be identified by the risk assessment, however experienced gas detection equipment manufacturers and their approved distributors are often able to help in this process, based on their experience of similar applications. However, it is important to remember that it is the end-user’s responsibility to identify all potential hazards.

It is also essential to identify the potential source of a gas release as this helps determine the number and location of detectors required for a fixed gas detection system.

Consider the environmental conditions

Honeywell gas detection
Sensepoint XCD
The performance, accuracy and reliability of any gas detection equipment will be affected by the environmental conditions it is subjected to. Temperature, humidity and pressure levels at the location all have a direct bearing on the type of equipment that should be selected. Additional factors such as potential variations resulting from a production process itself, diurnal/nocturnal fluctuations and seasonal changes may also affect the type of device which is suitable.

Understand product functionality

The next area of consideration relates to additional product functionality. Aspects like wiring configuration are important, especially when retro-fitting into an existing application. If the apparatus is being integrated into a separate safety system, certain communication protocols may also be required such as HART®, Lonworks or Modbus®.

Consideration will also need to be given regarding the requirement for local displays on transmitter units and local configuration of the unit and gas displays may also be a useful addition.

Measure the ease of use for operators and routine servicing personnel

Routine maintenance is another important consideration. Some gases and vapors can be detected with a number of different sensing technologies, e.g. Hydrocarbon gases with catalytic beads or Non-dispersive Infrared NDIR. Catalytic beads do not provide fail-to-safety operation and therefore can require a high frequency of routine maintenance, however NDIR based solutions tend to have a higher initial purchase price, but may require less routine maintenance. In-house resource to undertake such routine maintenance needs to be identified and in the absence of such a resource, budgeting for third party maintenance is an important factor in selecting the right equipment.

For more information on Honeywell hazardous or flammable gas detection, contact Arjay Automation by calling (800) 761-1749 or visiting https://arjaynet.com.

Thursday, January 31, 2019

Arjay Automation: We Solve Process Control Problems


Arjay Automation is a Manufacturer’s representative with extensive experience in the application and sale of controls and instrumentation for industrial and utility automation. Our real strength is solving problems in process control, flowmeter selection, analytical instrumentation, electrical watt hour metering, protective relaying and utility test equipment. Our sales people are technical and can offer help in applying technical products to meet our customer’s needs. Call us at (800) 761-1749 or visit our website at https://arjaynet.com.

Sunday, January 27, 2019

Wireless Technology in Industrial Automation

The use of wireless technology in industrial automation systems offers a number of potential benefits, from the obvious cost reduction brought about by the elimination of wiring to the availability of better plant information, improved productivity and better asset management.

However, its practical implementation faces a number of challenges: not least the present lack of a universally agreed standard. This article looks at some of these challenges and presents the approach being taken by Yokogawa.

You can download a PDF copy of "Wireless Technology in Industrial Automation" from this link.

Friday, January 11, 2019

Rotating Equipment Condition Monitoring: Critical to Safety, Production, and Profit


Rotating industrial and commercial machinery provides critical and non-critical functions to thousands of manufacturing and processing plants across many industries in the USA.

The detection of changes in a normal vibration pattern is one of several important parameters used to determine equipment deterioration and predict machinery breakdown. The sophisticated monitoring of vibration, along with other machinery operating variables, is known as condition monitoring.

By incorporating an equipment condition monitoring strategy for all your rotating equipment, everything from large large turbine generators to basic production line equipment, operators benefit from the establishment of planned maintenance outages and avoid the very costly down-time resulting from breakdowns and unplanned outages.

For more about equipment condition monitoring, contact Arjay Automation.
https://arjaynet.com
(800) 761-1749