{"id":553,"date":"2026-10-09T03:47:52","date_gmt":"2026-10-08T19:47:52","guid":{"rendered":"http:\/\/www.epcelonvalve.com\/blog\/?p=553"},"modified":"2026-10-09T03:47:52","modified_gmt":"2026-10-08T19:47:52","slug":"what-is-the-power-supply-requirement-for-the-e-h-pressure-transmitter-494e-88e3b2","status":"publish","type":"post","link":"http:\/\/www.epcelonvalve.com\/blog\/2026\/10\/09\/what-is-the-power-supply-requirement-for-the-e-h-pressure-transmitter-494e-88e3b2\/","title":{"rendered":"What is the power supply requirement for the E+H Pressure Transmitter?"},"content":{"rendered":"

If you\u2019ve ever worked in process automation, you know that even the smallest component can derail an entire operation. I\u2019ve been an E+H pressure transmitter supplier for over a decade, and one question I get asked more than any other is: \u201cWhat\u2019s the right power supply for my Endress+Hauser pressure transmitter?\u201d It\u2019s not a trivial question\u2014skimping on power can lead to erratic readings, downtime, or even permanent damage to one of the most critical tools in your process. Let\u2019s break this down in plain, practical terms, based on what I\u2019ve seen work (and what\u2019s cost my customers in the past when they got it wrong). E+H Pressure Transmitter<\/a><\/p>\n

<\/p>\n

First, it helps to remember that E+H makes pressure transmitters for every kind of process you can imagine: from food and beverage plants handling delicate sauces to oil and gas refineries operating at high pressure, and from pharmaceutical clean rooms to wastewater treatment facilities. Each application has unique needs, and E designs their power supplies to match that. But there are core standards that apply across almost all their models.<\/p>\n

Let\u2019s start with the most common type: loop-powered 4-20mA transmitters. This is the workhorse of industrial automation, and for good reason. They draw their power directly from the two-wire current loop that also carries the process signal. Most E+H loop-powered pressure transmitters have a power supply requirement range of 12V DC to 30V DC. Wait, that\u2019s a big range\u2014so why is that? It\u2019s not arbitrary. If you\u2019re installing a transmitter close to your control system, you can get away with the lower end, like 12V DC. The loop resistance will be minimal over a short distance, so there\u2019s no voltage drop to worry about. But if you\u2019re running that two-wire line 500 feet, 1000 feet, or more, the voltage drop across the copper wire adds up. Let me do the quick math for you: a 1mm\u00b2 copper wire has a resistance of about 0.018 ohms per foot. If you have a 1000-foot run, that\u2019s 2000 feet total (since it\u2019s a loop, you have to go and come back) of wire, so 0.018 x 2000 = 36 ohms. At the minimum 4mA signal, the current draw is 0.004A, so the voltage drop is I x R = 0.004 x 36 = 0.144V. That\u2019s negligible. But at the 20mA full-scale signal, it\u2019s 0.02A x 36 = 0.72V. Still not a big deal for a 12V supply, but wait\u2014E+H\u2019s transmitter needs a minimum voltage to operate. The key number here is the \u201cload voltage\u201d or \u201crequired supply voltage at the transmitter terminals.\u201d For their standard loop models, that\u2019s usually 11V DC. So if your supply at the control room is 12V, after a 0.72V drop at 20mA, you\u2019re at 11.28V\u2014just enough. But what if your run is longer, or you\u2019re using smaller wire? A 0.75mm\u00b2 wire would have a resistance of 0.024 ohms per foot, so a 1000-foot run would be 0.024 x 2000 = 48 ohms. At 20mA, that\u2019s 0.96V drop, leaving you with 11.04V\u2014barely enough, and if there\u2019s any other load in the loop, that drops further. I\u2019ve seen customers cut corners here, use a 12V supply, and then wonder why their transmitter glitches when the process is at full pressure. The fix? Either bump the supply voltage up to 24V DC (the most common choice for long runs) or use larger gauge wire. 24V DC is the sweet spot for most industrial loop-powered applications, because it gives you plenty of headroom for voltage drop. At 24V, after a 5V drop (which is more than enough for a 1000-foot run), you\u2019re still at 19V\u2014way above the 11V minimum. I always recommend 24V DC for new installations, unless you have a specific reason to go lower.<\/p>\n

Now, what about the newer, smart transmitters that use digital protocols like HART, FOUNDATION Fieldbus, or PROFIBUS PA? Wait, HART is usually still on the 4-20mA loop, so the power supply requirements are the same as above\u201412V to 30V DC, with the same voltage drop considerations. The digital protocols like FOUNDATION Fieldbus and PROFIBUS PA are different, though. These are multi-drop networks, where multiple devices share the same two-wire line. For FOUNDATION Fieldbus devices, E+H specifies a power supply of 9V DC to 32V DC, but it has to be a \u201cintrinsically safe\u201d rated supply if you\u2019re operating in a hazardous area. PROFIBUS PA is similar: the power supply is 9V DC to 32V DC, and it has to comply with the PROFIBUS standard for network topology and load. A common mistake here is using a standard 24V DC power supply from a loop-powered transmitter on a digital network. Digital protocols have more strict power requirements because they carry high-frequency signals, so you need a supply that\u2019s filtered to reduce noise. Noise is the enemy here\u2014it can cause bit errors in the digital signal, leading to communication failures. I always tell customers that if they\u2019re moving to HART or digital, they should use a power supply specifically rated for that protocol, not a generic industrial supply.<\/p>\n

Next, we have bus-powered or fieldbus transmitters that aren\u2019t loop-powered. Wait, some E+H pressure transmitters are designed for DeviceNet, or even wireless? No, let\u2019s stick to wired for now. There are also \u201cself-powered\u201d transmitters, though that\u2019s a small subset for very specific applications. Most are still either loop-powered or require a separate AC or DC power supply. For example, some of E+H\u2019s high-end pressure transmitters for extreme applications\u2014like high temperature, or high accuracy\u2014are \u201cline-powered\u201d with a separate AC input, usually 100V AC to 240V AC, 50\/60Hz. These are not loop-powered; they have their own power cord, and their output is a digital signal (like Modbus, Ethernet\/IP, or PROFINET) that\u2019s separate from the power. For these, the power supply is straightforward, but you have to make sure the voltage matches your plant\u2019s standard. Most plants in North America use 120V AC, while Europe and Asia use 240V AC, so E+H designs these to be auto-sensing usually, but it\u2019s always good to confirm with the model number. The power draw for these line-powered transmitters is low\u2014usually less than 10W, so you don\u2019t need a huge power supply, but again, noise is a factor. If you\u2019re powering a high-accuracy transmitter from a noisy AC line, you should use an isolation transformer or a filtered DC power supply to clean up the voltage. I had a customer a few years ago who installed a high-end E+H pressure transmitter for a pharmaceutical blending process, and his readings were fluctuating by 0.5 psi for no reason. It turned out he was powering it from the same circuit as a large pump that was causing electrical noise. We added a filtered power supply, and the problem was gone.<\/p>\n

Now, let\u2019s talk about hazardous areas, because that\u2019s a big one for many of my customers in oil and gas, chemical, and mining. If your transmitter is installed in a Zone 0, Zone 1, or Zone 2 hazardous area, the power supply has to be intrinsically safe (IS) or flameproof, and comply with standards like ATEX, IECEx, or FM. E+H certifies all their transmitters for these areas, and their power supply requirements will specify an IS barrier or a power supply that\u2019s rated for hazardous locations. A common mistake here is trying to use a standard 24V DC supply with an IS barrier that\u2019s not rated for the transmitter\u2019s power draw. For example, if your transmitter draws 20mA at 24V, the IS barrier has to be rated to handle that current and still limit the energy to below what\u2019s needed to ignite flammable gases. I always work with my customers\u2019 electrical engineers to make sure the power supply, barriers, and transmitter are all matched to the hazardous area rating. I once had a customer in Texas who tried to cut costs by using a cheaper IS barrier that wasn\u2019t compatible with his E+H pressure transmitter, and it caused a shutdown of a gas processing unit that cost him hundreds of thousands of dollars. Since then, we make sure every hazardous area project is double-checked.<\/p>\n

Another thing to consider is dynamic performance. E+H pressure transmitters are often used for processes that have rapid pressure changes\u2014like in hydraulic systems, or flow measurement applications. The power supply can affect how fast the transmitter responds to these changes. If you have a supply that\u2019s not providing enough current during a transient event, the transmitter might not update its reading fast enough, leading to inaccurate data. For loop-powered transmitters, a bigger wire gauge can help here, because it reduces voltage drop when the current spikes. For digital transmitters, a filtered power supply with low impedance is important to maintain signal integrity during transients.<\/p>\n

What about common pitfalls I see as a supplier? First, not accounting for temperature. Industrial power supplies have a temperature rating, and if you\u2019re installing the transmitter in a hot area (like a refinery process area that\u2019s 50\u00b0C or higher), the power supply\u2019s output voltage can drop, or it might not operate at full capacity. Always check the power supply\u2019s temperature range and match it to your installation environment. Second, mixing and matching power supplies from different manufacturers. E+H tests their transmitters with specific power supply models, and while many generic industrial supplies work, some don\u2019t meet the noise or voltage regulation requirements. I\u2019ve had customers bring me a transmitter that was working fine on one supply but glitching on another, even though both were 24V DC. It\u2019s always better to use a supply recommended by E+H, or at least one that meets their specifications. Third, forgetting about additional loads on the loop. If your two-wire line has multiple devices (like a flow transmitter, or a valve positioner) on the same loop, the total current draw adds up. You have to make sure the power supply can provide enough current for all devices, plus account for voltage drop. A typical loop-powered transmitter draws 4-20mA, so if you have two devices, that\u2019s 8-40mA, plus any current for the communication protocol (like HART adds a small amount, usually less than 1mA).<\/p>\n

Let\u2019s take a concrete example to tie this all together. Suppose you\u2019re installing an E+H Cerabar S pressure transmitter for a natural gas pipeline, running the two-wire line 1200 feet from the control room. Your process is in a Zone 1 hazardous area, so you need an IS-rated supply. What do you need? First, a 24V DC intrinsically safe power supply, rated for at least 30V DC output (to account for voltage drop). The two-wire line is 1200 feet, so using 1mm\u00b2 copper wire, total loop resistance is 0.018 ohms\/ft x 2400 ft = 43.2 ohms. At full 20mA signal, voltage drop is 0.02A x 43.2 ohms = 0.864V, so the transmitter will see 24V – 0.864V = 23.136V, which is way above the 11V minimum for the Cerabar S. Add an IS barrier rated for 24V, 20mA, and Zone 1 compliance. That\u2019s all you need, right? Not so fast\u2014if the pipeline has rapid pressure fluctuations, you might want a power supply with fast transient response, and a shielded wire to reduce electrical noise from the pipeline\u2019s equipment. I always recommend adding a surge protector on the power supply side too, to protect the transmitter from voltage spikes caused by switching equipment.<\/p>\n

Over my years as a supplier, I\u2019ve found that the best approach is to start with E+H\u2019s official documentation. They publish detailed power supply requirements for every model in their pressure transmitter line, including models for hazardous areas, digital protocols, and extreme environments. Don\u2019t rely on generic advice from the internet\u2014every installation is different. I offer free consultations to my customers, where we can go over the application, the installation distance, hazardous area requirements, and process dynamics to pick the right power supply. I\u2019ve had customers come to me after a bad experience with a mispowered transmitter, and we get them set up correctly on the first try, which saves them downtime and money.<\/p>\n

The power supply for an E+H pressure transmitter isn\u2019t something you want to cut corners on. It\u2019s the backbone of the whole system\u2014without reliable power, even the most accurate transmitter will give bad readings, or stop working entirely. Whether you\u2019re using a loop-powered 4-20mA model, a digital fieldbus transmitter, or a line-powered unit, make sure you match the power supply to your specific application, account for voltage drop, temperature, noise, and hazardous area ratings. And if you\u2019re not sure, don\u2019t guess\u2014reach out to someone who knows E+H products inside and out to help you.<\/p>\n

<\/p>\n

If you\u2019re working on an E+H pressure transmitter installation and need help picking the right power supply, or have questions about compatibility, feel free to connect with our team to discuss your needs and find the right solution for your process.<\/p>\n

Electromagnetic Flowmeter<\/a> References
\nEndress+Hauser. (2023). Pressure Transmitter Power Supply Guidelines. Endress+Hauser AG.
\nIEC 60079. (2021). Explosive Atmospheres. International Electrotechnical Commission.
\nISA-95. (2020). Industrial Automation Systems and Integration. International Society of Automation.
\nEndress+Hauser. (2022). Cerabar S Datasheet. Endress+Hauser AG.
\nPROFINET IO Specification. (2021). Profibus International.<\/p>\n

\n

Xi An’ Feng Yu Industry Co., Ltd<\/a>
We’re professional e+h pressure transmitter manufacturers in China, specialized in providing high quality products with low price. We warmly welcome you to buy cheap e+h pressure transmitter for sale here from our factory. For more discount information, contact us now.
Address: NO 1305,Fang Xing Building,Bei Guan No 35 Lian Hu ,Xi’ an City,Shaan Xi ,China
E-mail: info@fengyugroup.net
WebSite: https:\/\/www.fengyuinstrument.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

If you\u2019ve ever worked in process automation, you know that even the smallest component can derail … What is the power supply requirement for the E+H Pressure Transmitter?<\/span>Read more<\/a><\/p>\n","protected":false},"author":75,"featured_media":553,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[516],"class_list":["post-553","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-e-h-pressure-transmitter-47d0-892c1b"],"_links":{"self":[{"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/posts\/553","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/users\/75"}],"replies":[{"embeddable":true,"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/comments?post=553"}],"version-history":[{"count":0,"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/posts\/553\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/posts\/553"}],"wp:attachment":[{"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/media?parent=553"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/categories?post=553"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.epcelonvalve.com\/blog\/wp-json\/wp\/v2\/tags?post=553"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}