PROCESS CONTROL
ROCs & the process plant Heartbeart
Automated devices , processes and plants in the mining industry depend heavily on reliable information coming from the field . Without this information coming into the ROC , it becomes very hard for a site to trust a remote operating concept , as well as reducing the effectiveness of having an ROC in the first place . Endress + Hauser told IM : “ One of the key challenges in an ROC is knowing that the information coming from the field can be trusted . In a processing plant , a consequence of an incorrect level indication in a tank may result in the tank overflowing without detection for a long period of time , impacting yield and utilisation . The knock-on effect of a single device being inaccurate could result in a significant financial loss . Incorrect quality information may mean the plant is producing off-spec product , which has the potential to cause severe financial penalties for the mining company . Perhaps one of the highest risks for mining operations is the monitoring of environmental parameters . We have seen in the media in recent years the reputation damage that can be caused by an environmental breach at a mining company . Quality information and sensing capability at the field level will reap benefits when it comes to avoiding these situations .”
Advanced process control philosophies deployed at these plants require accurate , repeatable , and reliable information coming from the field . It is key that any field instrumentation is also able to self-diagnose and send health statuses to the ROC . Leading field instrumentation manufacturers now include smart diagnostics , verification capability and continuous device monitoring functionality to ensure maximum device reliability and accuracy . For example , Endress + Hauser uses Heartbeat Technology across its portfolio to empower smart sensors and instruments in the field “ Heartbeat Technology is a self-verification and monitoring software that enables diagnostics according to the NAMUR NE 107 standard , which are sent via a range of communication pathways into the relevant control system , asset management system or big data cloud solution . The visibility of device health using standardised indicators in the control system enables operators to determine if the data from the device is healthy . A quick glance at the relevant measuring point reveals the NAMUR status symbol , so that faults are quickly detected . The relevant error code can also be made visible using device software , such as Fieldcare , which allows for initial remote troubleshooting from the ROC .”
Field devices , such as flowmeters , require calibration to ensure that they are working as accurately as the specific site standard defines . However , calibration of field devices must be done manually in situ or , in some cases , the devices must be removed from the process to be calibrated . This not only means it is impossible to calibrate the device from the ROC , but availability of the plant is affected when the process is taken offline to calibrate the sensor . Heartbeat Technology allows calibration intervals to be extended by featuring verification across the portfolio . For example , with flowmeters , a remote verification can be triggered from the ROC using an asset management system or the control system . A traceable PDF report is generated and can be saved on the PC used in the ROC for record keeping and troubleshooting .
“ With technology advancing , field instruments often measure multiple variables from a single device , with many possible values that can be selected as an output . For example , a level device from Endress + Hauser with Heartbeat Technology can report a build-up value in addition to a continuous level value . This build-up value can be monitored from the ROC , which can then trigger a site TARP ( Trigger Action and Response Plan ) for cleaning the device . Endress + Hauser level devices can also utilise a self-cleaning function , triggered by this build-up value , to activate an air purge of the antennae and clear the build-up .”
Flowmeters from Endress + Hauser also bring additional information via digital communication to the control system . A Coriolis meter equipped with Heartbeat Technology can , for example , measure flow , temperature , density , viscosity , HBSI ( Heartbeat Sensor Integrity Index ) and more . This online , multiparameter information can be utilised to improve predictive maintenance of many different systems , including a lubricant loop , for example . The HBSI value can be utilised to identify build-up , corrosion or abrasion in the meter , indicative of the mechanical condition of the meter , and this information could be extrapolated across the pipes in the process . Some mining operators have reliability engineers , and analysts working in the ROC , as part of their centralised function strategy . By using this data , these teams then can implement an improved preventative maintenance regime encompassing the entire plant , using big data and analytical tools .
Electromagnetic flowmeters equipped with Heartbeat Technology can also detect process information , such as build-up in the meter . Remote water distribution networks managed in the ROC could utilise this information to develop an insight into the amount of build-up present across the network , enabling predictive maintenance for cleaning of the lines , rather than monitoring pressure or waiting until there is a blockage .
One of the key benefits of using an ROC is a reduction in exposure hours on site . The use of smart devices also brings a reduction in total labour spent maintaining these devices . Using pH probes in a leaching process often requires significant maintenance , regardless of the type of probe used . The conditions are very harsh , with poor process water quality used , harsh chemicals , slurries , and sometimes dangerous conditions . By utilising the most modern liquid analytical platform , Memosens coupled with Heartbeat Technology , one gold mine reduced the labour associated with maintaining these probes by 90 %, which is the equivalent of 2,000 hours per year . A reduction of labour can also be realised using digital communications during maintenance . With Ethernet / IP and PlantPAX , a faulty field device can be replaced in the field by a maintenance technician . The device can be commissioned by the operator in the ROC , using the settings from the old device . Using Ethernet / IP , a field device setting can be remotely and automatically set from the control system in the event of a power failure or device swap . ROCs currently use tools such as wearables and remote collaboration software to assist personnel on site to complete tasks they are not trained in . This saves substantial costs and enables the plant to use fewer staff compared to traditional staffing models .
Finally , Endress + Hauser has a strategic alliance with Rockwell Automation , which brings synergies such as reduced commissioning effort and time between Endress + Hauser field devices and Rockwell PlantPAX . Faceplates , add-on profiles , HART with ControlLogix and Ethernet / IP plugand-play capability unlock the smart field data and functionality of these field devices quickly and easily . Information and verification obtained through Heartbeat Technology can be easily shown and activated from the ROC . " ROCs are increasingly being used to monitor remote systems outside the processing plant , such as water management across an open pit , environmental monitoring stations and tailings dam monitoring systems . Innovative field instrumentation now features wireless connectivity and self-powered capability . These cloud-connected , batterypowered devices work very well in monitoring applications on mines . Endress + Hauser has now released an IIoT flowmeter and level device , capable of operating for extended periods without intervention . The data from these devices , regardless of location , can be brought into the existing big data platform being used by the ROC to enable visualisation of the information from the field , to the operator ’ s preference As mining operators continue their digitalisation journey , increasing the scope of ROCs in operating mines will continue to bring additional financial and safety benefits . Using smart field instrumentation and digital communication is a force multiplier in reducing site risk and optimising processes remotely ."
34 International Mining | JANUARY 2022