Confused by digital multimeter's "rel" feature

Thread Starter

ApacheKid

Joined Jan 12, 2015
1,450
I have two Siglent SDM3055 bench meters and they have "rel" feature, can be used for example to offset low resistance measurements where the lead's resistance could effect the readings.

But its confusing, it can be used for other kinds of measurements and the manual say very little about it:

One can press Math and in that menu see a "Rel Value" that can be "Off" or some value. Also in many modes like DC volts or resistance etc, one can also access a "Rel" setting and set it either on or off.

But its confusing, like if I go to Math and select Relative, it seems to have the ability to take the current reading as the relative value and save that, but it see inconsistent, and I cannot really make sense of it.

Does anyone here have these meters and can explain this? is there a quick way to zeroize the relative value setting?
 
Last edited:

SamR

Joined Mar 19, 2019
5,019
The only time I use the relative feature is measuring very low capacitance. Twist the leads together and use relative to zero before taking the capacitance reading. I only use it for zeroing the meter before taking a measurement to eliminate any component that the leads may induce.
 

Ya’akov

Joined Jan 27, 2019
8,964
One way to use REL is voltage offsets. For example, let’s say you want to display the difference from 5V to monitor a supply. Yo could just connect the meter and do the math, or you can set the REL with a 5V supply attached, then directly read the over and under.

The same is true for other ranges as well, of course.
 

Thread Starter

ApacheKid

Joined Jan 12, 2015
1,450
Short the leads and then press the Rel button to zero out any interference and lead resistance.
OK I guess its as simple as that.

I have another question now, I just updated the firmware to the latest version SDM3055_Firmware_V1.01.01.27R2 and see new calibration options. But there seems to be no published Siglent documentation for this, for example:

1683824612412.png

The bottom left has Calibration with a Factory option beneath it, but what does that do? is there really no documentation?
 

tautech

Joined Oct 8, 2019
377
OK I guess its as simple as that.

I have another question now, I just updated the firmware to the latest version SDM3055_Firmware_V1.01.01.27R2 and see new calibration options. But there seems to be no published Siglent documentation for this, for example:

View attachment 293991

The bottom left has Calibration with a Factory option beneath it, but what does that do? is there really no documentation?
No documentation ....yet, but it will come.
User Cal was a feature added a couple years back primarily to allow the correction of drift from the internal reference aging over time however that method was a PITA to use so it was made simpler so to be done entirely from the front panel.

These units do drift with time however a stretched datasheet accuracy spec meant they didn't drift from spec for a good few years operation but users required better so this easier user Cal was developed to allow customers to tweak ranges that they needed better accuracy from.
Immediately this new firmware was noticed by our customer Defpom from YouTube, Scott did a quick video on how to use it.
Like the previous User Cal I believe you can select Factory to return to the original cal.

 

Thread Starter

ApacheKid

Joined Jan 12, 2015
1,450
No documentation ....yet, but it will come.
User Cal was a feature added a couple years back primarily to allow the correction of drift from the internal reference aging over time however that method was a PITA to use so it was made simpler so to be done entirely from the front panel.

These units do drift with time however a stretched datasheet accuracy spec meant they didn't drift from spec for a good few years operation but users required better so this easier user Cal was developed to allow customers to tweak ranges that they needed better accuracy from.
Immediately this new firmware was noticed by our customer Defpom from YouTube, Scott did a quick video on how to use it.
Like the previous User Cal I believe you can select Factory to return to the original cal.

Much appreciated, thanks.
 
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