Chinese Electronic Load 500W module Sousim 500W - Page 1
Forum section: electronics / testgear

author: kawal
author_rank: Frequent Contributor
timestamp: February 15, 2021, 04:56:04 pm
content: I decided to take a risk and get one of these RS485 controlled electric loads. Haven't tested so far - waiting for a rs485 dongle .Spec are supposed to be 500W , 200V , 60A ,CV, CC, CW and CR modes.While build quality seems OK there is a slight problem that the system uses recycled power Fets . Fets seem original IRFP264 devices rated @ 250V .(legs are covered with shiny solder to a point , looks crusty close to case ).The design is very simple - basically a STM32 used to control 8 transistors via op amps.Read back of voltage and current is done by STM as well. The built in ADC/DAC are 12 bit so appropriate for such design from the 80c .There is 1 thermal sensors (transistor used as diod ) and room for 2 more sensors that would connect in parallel to the one populated.Fan is controlled from the ULN2003 - most likely PWN controlled.

author: samofab
author_rank: Regular Contributor
timestamp: February 15, 2021, 06:44:34 pm
content: I have similar unit. I plan to control it using ESP32, but I didn't come around to it yet. Works nicely using the dongle, though.I'm attaching a python script if you're interested.. (on second thought, I'm not sure if this is the correct one, but I'll leave it here until proven otherwise)

author: kawal
author_rank: Frequent Contributor
timestamp: February 15, 2021, 08:13:05 pm
content: Script seems to have errors . But thanks anyway.

author: kawal
author_rank: Frequent Contributor
timestamp: February 15, 2021, 09:07:24 pm
content: Tried connecting to the TX and RX port available on the board.Looks like I am able to get MODBUS RTU data

author: kawal
author_rank: Frequent Contributor
timestamp: February 16, 2021, 12:29:01 am
content: Well tested the unit from 1.5V to 31V and up to 5A loadthe read back was fairly accurate with a slight offset on the current readings of about 10mA .I was testing the different data groups on Modbus.The unit usesHolding Registers for settingsHR2 Enable/ DisableHR3 Overvoltage (20000 default =200.00V)HR4 Amp setting in mAHR9 Over current setting (5500= 55A)Input registers for readoutsIR6 Voltage ReadoutIR7 Current readoutIR8 Power readoutIR9 Resistance setting readoutThe fan was not spinning until the unit got hot 45..50C and the speed did change with temperature. So there is some kind of fan controlI lost communication while trying to change register HR5 and was unable to get it back. Hope it comes back to life.

author: ass20
author_rank: Regular Contributor
timestamp: February 22, 2021, 06:00:43 am
content: Hi. Are you buy this load from sousim taobao shop? You can found more software for this load on page of this shop. Main io protocol is modbus rtu. You can use any modbus rtu tools .. register definition avaliable ...if you do not have baidu account , please say. I can replace to other cloud.What is stm32 used on this load ? Thank you

author: kawal
author_rank: Frequent Contributor
timestamp: March 12, 2021, 08:29:38 pm
content: Quote from: ass20 on February 22, 2021, 06:00:43 amYes got the load from sousim taobaoI do not have a baidu account so I was not able to get any of the software.The processor is STM 32F100C8 with 12bit ADC and 12bit DAC . Possible to get more bits out of 12 bit adc via oversampling/averaging. Vendor claims 16 bit resolution.

author: vasinap
author_rank: Newbie
timestamp: May 10, 2021, 06:30:15 pm
content: Dear Sir,did You bring the load back to life? I faced the same and got lost.Hlp pls.Petr

author: syau
author_rank: Frequent Contributor
timestamp: May 11, 2021, 12:03:07 am
content: Quote from: ass20 on February 22, 2021, 06:00:43 amSoftware as per attached.

author: syau
author_rank: Frequent Contributor
timestamp: May 11, 2021, 11:46:33 pm
content: Quote from: syau on May 11, 2021, 12:03:07 amSome more software downloaded from the link in taobao. I haven’t test them nor do any virus scan. Use it at your own risk.

author: kawal
author_rank: Frequent Contributor
timestamp: June 04, 2021, 08:40:06 pm
content: I have not tried to get the unit working. Maybe requires a new processor not sure? I have a working unit if someone knows how to extract the firmware I can try.

author: mechanicalhand
author_rank: Newbie
timestamp: July 22, 2021, 06:53:05 pm
content: May be wrong modbus address, see this attachments !

author: ass20
author_rank: Regular Contributor
timestamp: October 16, 2021, 10:18:49 pm
content: if dc load do not answer from rs-485 you can reset to default uart baud rate.reset sequienceshort 2 pins in CON3 connector see pictureand on picture i mark swd pins fw may be do not locked....

author: MrDean
author_rank: Newbie
timestamp: November 26, 2022, 04:20:19 pm
content: Hi,I have problem with setting values for measurements. Only first (M1) work correct. If select some other points the I get a message that software not received data from power load after setting value. I tried with few softwares and works same. Don't get any message for other points....Does anyone had the same problem?Is the documentation and description of the registers available in English?Thanks

author: ass20
author_rank: Regular Contributor
timestamp: November 27, 2022, 09:21:46 am
content: Quote from: MrDean on November 26, 2022, 04:20:19 pmYou can translate 通讯协议.xlsx file from modbus.rarfor test you can use modbuspoll softaware. its work with mbp and mbw files from modbus.rar

author: killingtime
author_rank: Regular Contributor
timestamp: May 01, 2023, 06:49:16 pm
content: I pushed the xls through Google Translate. The translation is a bit rough but it's better than nothing. Attached in case it's of use to anyone.

author: Atom
author_rank: Regular Contributor
timestamp: May 06, 2023, 06:21:44 pm
content: Quote from: killingtime on May 01, 2023, 06:49:16 pmthank you, i have the 150w version of this and at first it worked really well now i dont know why it works,(using modbus poll) but i cant seem to get data back, so for examle i cant see any of 30000 registers, previously i could read for example the measured current and voltage. now they are all zero.40000 registers work as intended, i can set for example currents in CC mode and the load will pull the specified current from the PSU, but registers on the pc interface will still stay zero no matter what i do .what could have happened? did i fry the adc on the stm32 ? did anyone had the same problem?

author: ass20
author_rank: Regular Contributor
timestamp: March 25, 2024, 08:02:16 am
content: new software link from sousimhttps://pan.baidu.com/s/1S3htO5PCUhFOIF1yrdYMMAPassword: 1111I have 200W module version 1.0but i do not know what is voltage and current limits...Any body have sousim contacts?

author: tomoliva
author_rank: Newbie
timestamp: June 30, 2024, 06:56:09 pm
content: I tried at Baudu but an account required - anybody out there with an account ?Latest version is dated 25th May 2024- so looks like it's a product that's being worked on....

author: ass20
author_rank: Regular Contributor
timestamp: July 23, 2024, 04:10:41 pm
content: tomolivause baidu cloud app for accset to baiduForanybody can download firmware from stm32 ? i have old version of ВС load but pulse and list mode do not work..i add modbus.rar from sousim cloud (file date 02.07.2024)

author: mechanicalhand
author_rank: Newbie
timestamp: August 12, 2024, 08:36:43 pm
content: Dumps from my 500w electronic load modules

author: Circlotron
author_rank: Super Contributor
timestamp: August 12, 2024, 09:05:02 pm
content: I like how “QC PASS” is silk screened onto the board before it is even assembled, let alone tested.

author: H.O
author_rank: Frequent Contributor
timestamp: August 13, 2024, 07:32:19 am
content: What's the problem with that?If it doesn't pass they simply grab a black marker and cross over that [QC PASS]. THEN they'll ship it.

author: ass20
author_rank: Regular Contributor
timestamp: August 13, 2024, 05:36:33 pm
content: dump form old version 200W and pcb name Practical version 1.0.0

author: ass20
author_rank: Regular Contributor
timestamp: September 23, 2024, 08:05:02 am
content: HiPlease download dumps of stm32 cpu wirh stlinkCpu is not lockedPlease !!!

author: BennoG
author_rank: Frequent Contributor
timestamp: September 30, 2024, 08:11:20 am
content: For those who have communication problems. On my version the DC/DC converter for the isolated RS485 communication stopped working on my version (after power up it works for 5 seconds and then the DC/DC converter drops to 0V)Pin 5 and 8 on U4 should have 5V dc. At the moment investigating how the DC/DC converter works.Benno

author: ass20
author_rank: Regular Contributor
timestamp: November 29, 2024, 07:31:54 am
content: hiAnybody use dynamic mode on this load ?