In recent years, the development of smart field equipment has been a topic that everyone likes to discuss. The vast majority of the discussion focused on the new features of Transmitter, but there were also complaints about how difficult it was for the control system to obtain additional information, perhaps because the old device-layer network could not handle such a need.
The emergence of such problems is closely related to the current state of the industrial network of manufacturing plants. Most of the production plants that have been running for more than a few years have used a wide range of automation equipment since their initial construction. And just like the "barrel principle" (how much water a bucket can hold depends on the shortest plank), the overall performance of the system will not be better than that of its oldest equipment. This is common in field device networks that employ common analog volumes.
Control system vendors have been providing a wide range of functions that are much more complex than simple analog I/O for quite some time. Although many companies still use this old, outdated instrumentation system, HART-enabled I/O has been around for several years. Most companies that equip HART equipment and facilities have been using HART5 since the 90s. The latest is that several major system vendors have introduced configurable I/O that can be modified by software or hardware modules.
This configurable I/O provides users with the latest features to interact with smart devices and realize all the benefits they can provide. Configurable I/O enables full interaction with the increasingly common HART6 and HART7transmitters and enables bidirectional communication with the device with all the latest diagnostic data and control systems.
Many large companies in the process industry, including refinery operators, see this as an important technological advancement that can completely simplify future items. Devices with advanced HART capabilities provide sophisticated communication paths with lower implementation costs, simpler troubleshooting, and greater flexibility.
A huge improvement
Automation is the infrastructure that underpins the process process. Therefore, those who design automation systems must meet the needs of chemical engineers and other process designers. If one of the elements changes, the automation system must adapt to the change, as this change can disrupt everything and make the automation system the most critical access to an item. Not all automation hardware and systems on the market can be easily adjusted according to those new changes.
Most automation devices are designed for specific applications and are therefore highly individualized. This makes it expensive, expensive to change, requires a lot of engineering, and requires a lot of documentation and testing work. Being able to use off-the-shelf devices with fewer means of communication and more standard protocols would be a huge help.
Many users are very enthusiastic about the new configurable I/O systems that are already on the market. They see through systems like this that suppliers are really listening to them and are willing to make more progress in flexibility. There are two things that HART function meter users repeatedly mention and want to get rid of: the marshalling cabinet and the HART multiplexer. Configurable I/O can get rid of both.
So what exactly is the problem?
To be honest, these advancements are considered wonderful. But the constant problem is the setup of the device. Over the past few years, the number of parameters that need to be set for a typical smart device has increased significantly. People who need to set up through the keyboard have to deal with such situations with endless questions and answers. The specific amount of parameters varies from device to device, but it always takes some time to set.
There are users who work with suppliers to develop pre-set devices. When the user receives the device, the transmitter is already equipped with measuring range, engineering units, alarms, etc., so it can be plug-and-play. These jobs provide you with all the information you need at the time you need to book your equipment, i.e. early in the process. This also means that the specifications cannot be changed between ordering and installation and commissioning. These qualifications reduce the usefulness of this approach.
Some users ask, "Why can't we let the system do the setup for us?" The control system has all the information it needs to get from known field equipment. It knows that the PT215's Measuring range is 0-30psi, and that it will trigger an alarm at 25psi, etc. All this information is available in the system and is updated at all times. Why do technicians have to look at this information and manually enter it into the device? ”
Recently, TimmMadden, a senior instrumentation and control consultant at ExxonMobil Development, gave a report to Yokogawa's user base titled "This Is How It Happened." He talked about the many ways companies are taking in refining items to keep automation from becoming a critical path. The goal is to make automation invisible. Problems that do not know where they arise almost never occur, and automated systems are solved from the very beginning of the problem.
ExxonMobil is a well-known company in dealing with automation issues, and it also presents many challenges to suppliers. Some of Mr. Madden's reports are about technology, others about programmatic, and he also spends quite a bit of time talking about smart device settings. He introduced a system called "DICED" that ExxonMobil is using.
Mr. Madden also noted that ExxonMobil wanted to standardize the hardware and implement all individual item requirements through software. Field cabinets with configurable I/O should be stocked, ready to ship at short notice, fully tested, ready-to-install equipment. All information is obtained from the control system via the network, so technicians practically do not need to do anything other than connect the equipment cables. All are pre-tested, and the amount of documentation required is greatly reduced.
He said that installing such a smart I/O cabinet on site would require nothing but an optical cable to the control center and redundant power supply. For field equipment, the old marshalling cabinet required 15 to 25 terminal blocks from each device to the control system, but now only 5 are needed: 2 on the equipment side and 3 on the cabinet side. ExxonMobil did not use a fieldbus network and preferred HART equipment. Mr. Madden's argument is that this approach to smart I/O cabinets makes it no longer important to distinguish whether the technology used in the field is HART or fieldbus, and the system architecture and the functionality available are essentially the same.
The gap between reality and imagination
The technology necessary to support the "DICED" system does not yet exist. But how far are we from it? ExxonMobil believes that the HART6 and HART7transmitter are now available and that the new I/O system should be able to support it. In preparing this article, the authors asked the four main production instrumentation and configurable I/O vendors, "How far are we from achieving this?" As a result, no one answered.
It is possible that there is more progress in this area than we know, or that some vendors are trying different approaches, but the goal is similar. Let's leave the answer to time.
Smart device settings
According to Timm Madden, a senior instrumentation and control consultant at ExxonMobil Development, when using DICED (see below for what each letter means), and connecting a new HART6 or HART7 device to the control system via configurable I/O, the process is as follows:
Detect (D) - When a new HART device is connected to configurable I/O, the I/O channel detects that current is flowing in a direction that was not previously flowing. That means adding a new device.
The Ask (I)-I/O channel will transmit HART commands requesting the equipment label. Devices with HART function return their tag name. If the new equipment is not a HART functional device, such as a shut-off valve, then it is clear that it will not be able to respond to the request. In this case, the DICED process is terminated, but a report is still generated to the user informing the user of a change in the wiring in the field, most likely a new DI or DO device installed.
Configuration (C) - Once the system has detected and identified a new HART functional device, the system can set its scope, engineering unit, and other configuration information. Our plan is to purchase field devices that have only been pre-configured with tags, and then configure the field devices accordingly by systems that usually have up-to-date data.
Enable (E) - We assume that the field devices are already configured by the system and are part of a specific control policy. Note that our item execution process is based on the assumption that we will do most of the design, configuration, and testing in a virtual environment, but we may not know which I/O channel each field device is set up through.
So in this step, the system knows which I/O channel the new device is connected to and develops the logic between the contact control policy and the field device. Once this is done, the field device and the logic associated with it are put into use.
Document (D) - Assuming all the above steps are completed successfully, we expect the system to report this success through the event log. The vision we are looking forward to is that we can greatly simplify the field commissioning process, which currently requires paper folders and extensive field visits.
We also believe that the system can automate the testing work that currently involves an engineer or operator sitting in front of a console and contacting the field team via radio. For example, if the detected device is a control valve, we can send an analog output to the valve and read its position via HART. We can therefore assume that the valve is working properly, not jamming, that its failure mode (fault opening or closing) is correct, and that its position is correct within its travel range.
One of our views is that all electronic circuits that need to perform DICED are included in the configurable I/O modules. The problem now is to get the software to work so that we can get the most out of this hardware. Note that DICED does not require changes to the field equipment itself.