Seek help regarding electromagnetic interference issues with the instrument cables of deep well pumps

Hehe. 1. Such applications are quite common; the probes are usually routed through pipes together with submersible pumps. 2. Well, it still depends on the level gauge itself having strong resistance to power-frequency interference – otherwise, even if it’s enclosed in gold-plated pipes, it won’t work properly. 3. In my village, model C26W is used extensively for water injection in the Xinjiang oil fields; it’s been in use for over 10 years without any issues caused by pump startup interference. 4. Hehe, 13709170262

Reply to 2# Shike Instruments: Could you provide me with the manufacturer and model of the level gauge you use?

This post was last edited and replied to by Shuaike Instruments on 2012-1-2 at 15:06. Reply 3# ratly: 1. I’m an old hand from the R&D department of Shuaike Instruments; I also work part-time as a technical support specialist. Everyone in our circle calls me “E Lixiao Guai”. Hehe, one of my tasks is to collect difficult problems and prepare development proposals. 55555555 My phone number is listed here, but it’s not good to leave it – otherwise I won’t be contacted anymore. 2. The selection information for C26W is attached for your reference. Please pay attention to the details of its specifications. To make a good diving instrument, there are essentially three key factors: first, impermeability; second, the stability of the amplification circuit; and third, the electrical encapsulation structure of the casing. The structural design is crucial, and the diving probe itself must serve as an effective grounding element! There is then no longer any need for external grounding or shielding measures~~~~~~~ Moreover, for civilian electrical equipment, the required grounding resistance is ≤1Ω; in some facilities with strict requirements, such as pharmaceutical factories, the required grounding resistance is ≤0.2Ω. When the grounding resistance does not meet these requirements, interference can \"crawl\" from the ground into the equipment ,,, This possibility is actually quite high. Note: Textbooks don’t mention anything like this; whether it works or not depends on each individual. 3. Pay attention to the details of the indicators in Jake’s information – those who understand it can draw parallels and see things clearly, haha. Once one has clear understanding, they can decide which product to use; there are really many good products available in the market. attach]839231

The following suggestions are for reference only; I hope they will be helpful to you. 1. The submersible hydrostatic level gauge has a grounding terminal, so connect that terminal to the ground. 2. Use shielded cables for the signal wires coming from the transmitter to the DCS or secondary meters, and ensure single-point grounding; this is generally done on the cabinet room side, that is, on the side of the secondary meters or DCS. The other end of the shielding layer must not be connected to ground.

Reply to 5# uddmcipyud: Thank you for the reminder, but... 1. The gauge head is properly grounded. 2. The gauge shows no reading, and this has nothing to do with the shielding grounding of the cable connecting it to the DCS

Reply to 4# Shike Instruments: Thank you very much. You must be an expert. I have a question – I would like to prove that your company’s instruments can be used in my application. In your document, it states that \"For electromagnetic wave/radio frequency interference: the error of the primary signal at the probe section is < 0.5% FS under interference at 10–300 MHz and a field strength of 15 V/m.\" How can I determine whether the interference levels in my operating conditions are below this threshold? In your opinion, what are the main issues with the gauge I’m currently using? Poor header interference resistance? Is the cable unshielded? Too close to and parallel to the motor cable?

Reply to 7# ratly: 1. “Electromagnetic waves/radio frequency interference” refers to spatial electromagnetic fields, such as high-frequency interferences like mobile phone signals. 2. In industrial environments where submersible pumps, large motors, and inverters are present, there isn’t much radio frequency interference (after all, no one stays close to the transmitters while using their mobile phones, haha). The main type of interference is low-frequency interference in the range of 5Hz to 300Hz (power frequency). 3. As for power frequency interference, I don’t recall any instrument manufacturer providing specific specifications for it. The common practice among developers is to evaluate a meter’s ability to resist power frequency interference based on the static stability of its measured values or output signals, that is, how many digits change during transient signal variations. For example, with the C26W model, when the reading at zero is 4.0000 mA, the fourth digit after the decimal point should not change by more than 2 digits during transient variations. However, many transmitters on the market see changes in the third digit after the decimal point, or even in the second digit, haha. This means that in a normal, natural environment, which is also one filled with electromagnetic interferences of various frequencies, the more stable a meter’s signal is in such an environment, the stronger its resistance to interference must be. What else can this indicate? I guess no electronic engineer would object to Russia’s view, right? 4. For 4–20mA instruments with two wires, if the circuit design is robust enough to resist interference, then even when using unshielded twisted pair cables for transmission, it’s difficult for the signal to be disrupted or affected by interference. This is like having peace of mind in chaotic situations. 5. For submersible instruments used together with submersible pumps, there are two concerns: first, the circuit design might not be sturdy enough; second, the shielding layer of the level sensor cable and the stainless steel probe might not be properly connected to each other Well, you might as well measure the resistance between the two to see if there’s a connection. I guess over 99% of commercially available submersible level gauges are just two separate components, right? Russia takes this opportunity to remind those who do the same work: 6. Other products have text that jumps around; but is it certain that our product won’t have such issues? Well, regarding this matter, it’s hard to be absolutely certain. It’s also possible that other meters work fine, but suffer from extremely strong interference. Russia’s approach is as follows: first, understand the operating conditions thoroughly; second, incorporate specific measures during product manufacturing; third, provide guidelines regarding the proper use of the products; and fourth, in case the product doesn’t perform well or bad luck strikes, accept defeat and offer a full refund. 7. Hehe~~~~~~~~~~~~~~.

1. I remember that day; it was probably in the middle of the night? I’ve typed quite a lot to answer the original poster’s question; I wonder if the original poster has seen it? ,,, Now I can’t remember either what kind of bird it was… 55555. 2. Russia is the type that speaks without restraint, following their impulses; who knows what will happen to them next… they might get killed again… 55555555555. Russia decides to hold a funeral for themselves in advance… 5555555. 3. If the poster has any questions or is unsure about something, they can contact Russia. Russia usually responds by sending an email, organizing the information in points 1, 2, 3, 4, so that the issue can be explained clearly