IEM 3255 Not giving consistent pf values.

[Sabyasachi]

Hi All,

I am facing an issue with reading the RS485 data with the IEM 3255 Energy meter.

When I am trying to see the pf from the meter screen itself, it's showing me as -0.84 as shown in the image.Meter screen

However, when I'm trying to read from RS485 Bus, particularly, I am reading the register 0x0C0B, I am getting a response as " BF 8D 6F DA ". 

This value, which is in IEEE754 floating point format, If I convert, I'm getting as ' -1.1049759 '. 

Can anybody help me out with this problem?

The meter is connected in 3P3W configuration, all CT ratios are correct and even wiring type is correct.

[Charles_Murison]

Hello @Sabyasachi 

I believe the link below is for the PM5500 series but I believe the format is the same
https://www.productinfo.schneider-electric.com/pm5500/595e2aa946e0fb0001f715da/PM5500%20User%20Manua...

The PF value is calculated from the PF register value using the following formulas:

Quadrant	PF range	PF register range	PF formula
Quadrant 1	0 to +1	0 to +1	PF value = PF register value
Quadrant 2	-1 to 0	-2 to -1	PF value = (-2) - (PF register value)
Quadrant 3	0 to -1	-1 to 0	PF value = PF register value
Quadrant 4	+1 to 0	+1 to +2	PF value = (+2) - (PF register value)

Regards,

Charles

[Mehran_Mehrnia · Accepted solution]

Hi @Sabyasachi 

As Charles mentioned correctly, iEM3000 series the same as PM5500 series perform a simple algorithm to the PF value then stores it in the PF register.
iEM3000 Power factor register format

Thank you.

Best Regards,

-Mehran

L3 Expert Tech Support Specialist