Range of the power factor register (Modbus Register number 3150, Power Factor Total) of ION9000

[Tomohiro-Okada]

Hello,

I have two question about power factor register(Modbus Register number 3150, Power Factor Total) of ION9000.

I think the relation between the display value of power factor and the internal register value is below.

Display Value：0.0000LG～1.0000LG　⇒　Register Value： 0.0000 ～ -1.0000

Display Value：0.0000LD～1.0000LD　⇒　Register Value：0.0000 ～ +1.0000

(Finally, the range of the register is -1.0000 ～ 0.000 ～ 1.0000)

Is my understanding correct?

Another question is that if the display value is 0.0000LG, the register value can be like -0.0000?

(the register value is expressed by adding sign to zero?)

I'd like to know how to distinguish Lag or Lead by using register value (3150 Power Factor) when the value is zero?

Thanks,

@Tomohiro-Okada 

[DanL · Accepted solution]

The ION9000 supports two different methods for presenting a sign for power factor via the "PF Sign Convention" setup register in the Power Meter Module.

https://www.productinfo.schneider-electric.com/ion9000/595e26f146e0fb0001f6ffc4/IONReference/English...

The supported sign conventions for the signed PF outputs are:

1. "IEEE": The sign encodes Lead vs Lag. Quadrants 2 & 4 (Lead) are positive. Quadrants 1 & 3 (Lag) are negative.

2. "IEC": The sign encodes the direction of flow of active power. Quadrants 1 & 4 (delivered) are positive. Quadrants 2 & 3 (received) are negative.

When the PF Lead registers are > 0.0, the PF is Leading
When the PF Lag registers are > 0.0, the PF is Lagging

[Tomohiro-Okada]

Hello @DanL 

Thank you for your reply.

I understand relation between Quadrants and register value(Modbus Register 3150) .

(The relation between them is changed when the meter setting is "IEEE" or "IEC")

Then, can the Modbus Register  value be following numbers?(when the meter setting is IEEE)

・　－1.0000 (I think the value means same with 1.000)

・　－0.0000 (If the register can be the value, I think it means power factor is zero and lagging)

I was asked  by my customer to tell them available  value  of the register( Modbus Register 3150).

Regards,

@Tomohiro-Okada 

[DanL · Accepted solution]

Register 3150 is computed as:
PFtot = Ptot / Stot * signConvention

where Ptot = (signed) total active power and Stot = (unsigned) total apparent power

NOTE: ION meters support two definitions of total apparent power. Please ensure the meter is configured to use the appropriate definition. Utilities tend to prefer "Vector Sum". Demand customers often prefer "Scalar Sum".

while using the IEEE setting, signConvention = -sign(Q)

where Q = reactive power

values that end up exactly on a boundary between quadrants are technically neither lagging nor leading (ie. -1, +1, -0, +0)

A values of -1.000000 and -0.000000 are much more likely when there is a nonlinear load (causing distortion) and you are using the default "Vector Sum" method for kVA_total.

[Tomohiro-Okada]

Hi @DanL,

Thank you for your prompt reply.

I understand about this.

Thanks,

Okada