OHR Multifunction Process calibrators [OHR-C03] - Page 1
Forum section: electronics / testgear

author: DaneLaw
author_rank: Frequent Contributor
timestamp: December 29, 2024, 09:10:56 pm
content: Has anybody tried these multifunction process calibrators from OHR?Looks to be from a Chinese company called Hongrun Precision Instrument Co. that seems to be making various displays, thermostat PID controllers, isolators, temperature-pucks etc for for the industrial market, so more or less the same product-segment where these process calibrators are intended.OHR-A03 seems to have the highest tolerances with a peak at 0.01% while OHR-C03 seems to be the most feature-rich, but peaks at 0.03%OHR-A03 & OHR-C03Purchased one a few months back, [OHR-C03] the unit that got graphical display & more features.Tried to purchase it from the company, and even though they would gladly sell at very attractive domestic CN prices, but all foreign sales, they wouldn't only to domestic addresses. had to rely on a third-party seller, who tends to put quite a mockup on these regional items.It does give you control down to a microvolt, but it does take quite a few minutes from boot before it centers at 0µV, it will also do minus.Got three voltage sources ranges 110mV, 12V and 24V.110mV range.Org English manual attached with tolerances.

author: danno_cj
author_rank: Contributor
timestamp: December 30, 2024, 10:16:37 am
content: The only feature that OHR-C03 has over LB02A is the graph on the screen. Outgoing signals have a bit higher precision on LB02A and the price is almost half. The other one is better but also several times more expensive compared with LB02A.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: December 30, 2024, 12:18:21 pm
content: Quote from: danno_cj on December 30, 2024, 10:16:37 amIts night and day, but you can check the manual for some of the details..(posted above)If you just want a cheap calibrator with also tons of programming features .. SG003A from Fnirsi is also a decent choice.. its the best bang for the buck.. can be had for around 45 bucks and would personally prefer that over the LB02A that is a dated unit on so many aspects that I value, but it likely comes down to many of the things I tend to use these devices for.https://www.eevblog.com/forum/testgear/fnirsi-sg-003a-sg-004a-signal-generators/msg5714555/#msg5714555But there is a lot of these no-name devices.. you can get them for as little as 15 bucks if you want the cheapest.These units above is a from a maker that specialize in making these industrial controllers that relies on these testdevices..

author: danno_cj
author_rank: Contributor
timestamp: December 30, 2024, 01:29:26 pm
content: On current and voltage source LB02A have 0.025% and OHR-C03 have 0.05% accuracy. To my eyes LB02A is more precise tool compared to OHR-C03. Also the are many tests on YouTube regarding LB02A and those conclusions is: accuracy is spot on. There is no independent test about OHR-C03. Since you have this device make one, show us what are good features and bad aspects. When you are dealing with microvolts you also need very high precision. Higher resolution don't bring higher accuracy.Don't compare Fnirsi devices with anything because almost all appear to be toys.Off topic: don't quote my post since no one wrote something between our posts. Is not needed.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: December 30, 2024, 10:52:14 pm
content: Quote from: danno_cj on December 30, 2024, 01:29:26 pmI quote what I want in this thread.. particularly with certain characters.And it goes without saying' if you like your LB02A or even the 15$ LB02G or some of the other cheap variants that are on the Chinese fleamarket (in bulk) then kudos to that, but for my use cases, it simply wont do.. Way to limited (dated if you will) with its two sockets, ltd display alongside a MicroUSB, and won't do the things that I tend to use these devices for.So it simply isn't an alternative... Its an old model, that most people are familiar with.All these extremely cheap LBxxx models or perhaps clones that are pouring out of China or even the cheap process calibrators that come in a DMM form-factor like Mustool or TOOLTOP ET72.. Are likely good value for some, not least in lack of better, but as I emphasized, I would take a Fnirsi SG00xA, not least the SG004A any day of the week over these relatively dated 2 sockets variants and models that look more like these older mash-up Fnirsi products from the past - than the current Fnirsi variants of SG003A / SG004A and you will also get higher peak-tolerances with a Fnirsi SG004A than this LB02A you seem to have, not least if you take all their specs on face value.As explained its night an day, on the possibilities, but you can look that up on your own behalf, or check the details in the other thread, and please drop this childish behavior "Fnirsi is a toy", with an underlying narrative that my cheap Chinese LB02A ain't.They are all toys... though for the end-user that gets a meaningful use out of it - Its a useful tool that likely matches that person's budget and fascinating to see such precision at these relatively low prices.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: December 30, 2024, 10:55:06 pm
content: For your "independent reviews" of these OHR-A03 (0.01%) & OHR-C03 (0.03%) your best bet, is to surf the Chinese forums.. it ain't models that OHR seems to have any interest in porting to the Western world or any third-party Amazon stores that will grease western influencers with freebies in exchange to dump them on western consumers like we see on YT from time to time.OHR seems to mainly prioritize the industrial segment.There are tons of Chinese test devices that we simply don't see here on the western market' so you have to do your homework - some due diligence efforts.. and often you simply cant find info on these foreign items, but there is also a joy in trying out new devices that haven't already been analyzed five ways to Sunday.I personally like going down these rabbit holes and finding test-devices that I haven't seen before and cant find any user feedback or YT videos, but that's me... I get that many want some assurance, and maybe prefer that other people can vouche or that some social media influencers can guide them, before taking the plunge.These models from OHR-is jacked with features...and why they have 5 banana sockets, alongside TypeC and USB3-A, that seem to be used for compensation (int/custom/ext) it also came with a small thumbstick, that looks like a USB thumb drive, with a USB-3 interface, and written ext cold junction compensation.On this "03"-model it also refers to.Recording function, RS485 function, HART function, TTL function, Bluetooth function, AC measurement..but to what extent.. don't know yet.Many of these aspects, are optional features where you need to go pretty far up the price ladder on high-end models to acquire, so it's really not apples to apples with these 2 sockets LBxxx models with MicroUSB, which can be had as low as 15$ for some of the variants (LB02G)Alongside you have minus, microvolt tolerances down 1uV entry sensitivity, 1A measurement ablelity (if I recall) and also way higher resistance and frequency ability than fx LB02A, and you can program various aspects of these things, and features that seems to be common on the more adv process multifunction signal process calibrators and having waveform ability for both source & measure.. its a pleasure to visualize signals, not least relative fast moving signals or variables over long time.. you can adjust the graph on its acquisition time from 00.1s to 60.0..Havent seen any menu so far about end-user calibration, but then again I don't have the reference source tools to deliver finer tolerances or even validate some of these specs with any meaningful certainty.As mentioned it takes quite a few minutes before it finally settles down at 0uV.. it will start at around -6 to 8uV and then slowly center... it takes a long time before it reaches 0uV. like 10 to 20 minutes but could be the norm when dealing with such minute values.

author: tutochkin
author_rank: Contributor
timestamp: July 04, 2025, 06:37:55 pm
content: The name is different, but the essence seems to be the same...https://aliexpress.ru/item/1005008269170524.html?sku_id=12000044429087144The price is about the same as MR9270S +https://aliexpress.ru/item/1005008725857786.html?sku_id=12000046410049182&spm=a2g2w.productlist.search_results.1.3bbd7a87UCYKI0

author: DaneLaw
author_rank: Frequent Contributor
timestamp: July 04, 2025, 08:28:17 pm
content: Quote from: tutochkin on July 04, 2025, 06:37:55 pmtutochkin, pls use clean international links to Aliexpress on the two you posted, as both the RU-label alongside ID will take western people for a round-about with puzzles, and possibly mess with people Aliexpress settings/cookies.Clean link example:https://www.aliexpress.com/item/1005008269170524.html.Quote from: tutochkin on July 04, 2025, 06:37:55 pmYep. there are a few rebrands of OHR models, I don't know if they perform according to OHR specs, but when I looked into it some time back, I was left with the impression that it could simply be down to regional labelling from Hongrun Precision Instruments..As in "OHR"-product labelling could be China, and the NHR label intended for international market and western resellers as they have a tons of industrial system-controllers that seems optimised for the western market.The "NHR" labels seem to be what is used on OHR Hongrun's English worded site."NHR" product labellinghttps://en.hrgs.com.cn/Nhrshop/?type=list&category=6While its "OHR" on their main domestic Chinese site:https://www.nhrgs.com/ohrshop/?type=list&category=321But the prices do vary a lot.. also listed on Amazon to 640 $ (US Only), and that listing it looks like the seller tried to blur the OHR label.https://www.amazon.com/NURII-Calibrator-Simulator-Transmitter-Thermocouple/dp/B0DKSZVF9F?That is like 7 fold more than the prices I was presented by Hongrun, even though it was a no-go to ship to anything other than to a Chinese address.But both the programmable multifunction C-03 with 0.03% and the B-02 with 0.01% are being sold with a heavy mock-up by third parties.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: July 04, 2025, 08:42:54 pm
content: IN & Output settings.You can adjust the time aspect on the refresh-rate of the graph(s)..