Onset EG4xxx Configuration Guide
(for firmware v3.1 or newer)
Onset Computer Corp
470 MacArthur Blvd
Bourne, MA 02532
http://www.onsetcomp.com
800-564-4377
loggerhelp@onsetcomp.com
April 18, 2018
1 Overview
This guide explains how to configure the Onset meter so it properly reflects the physical reality of an installation. There are three sections to this guide: the first is a brief introduction to the web pages used
to configure the Onset meter, the second is the main section and consists of a list of examples reflecting
common installation scenarios. The third section contains tips on how to fix up installation mistakes through
the web configuration rather than having to go out to a site and correct the physical mistake.
Onset establishes a few basic rules. Following these rules is not strictly required, but they help to keep
things straight and properly working:
1. The direction in which the Current Transformers (CTs) point matters. The white sticker on the CTs
should always point towards the entity being measured. For example, towards the utility when
measuring power from the power grid, towards the inverter for solar and/or wind generators, towards
appliances when measuring loads, or towards the panels when measuring subpanels.
2. Power readings that are positive numbers indicate that power is being delivered from the entity be-
ing measured whereas negative numbers indicate power being delivered to the entity. For example,
when a solar system produces more power than a site uses, the excess power is delivered back into
the grid. In this case, the power reading for the grid will be negative, since the grid is consuming the
excess power.
1
Onset EG4xxx Configuration Guide 1 OVERVIEW
To configure the meter, start a compatible browser on a computer and connect to the device’s web page.
See the Owner’s Manual for details on how to do that. Once connected to the device, click on the “LAN
Access” link in the top-right of the page. This redirects the browser to a page ensuring a direct LAN
connection to the device. If the page does not load, you will not be able to make changes to the device
settings, unless remote administration is enabled. Please contact Onset technical support for details on
how to enable that. Once the page has loaded, click on the “Settings” link in the top-right of the page,
then click on “Installation” in the navigation-bar on the left of the new page.
As illustrated in Figure 1, the Installation page has five sections:
1. Potential Transformers (PTs)
2. Current Transformers (CTs)
3. Remote Devices
4. Registers
5. Totals and Virtual Registers
We describe the purpose of each section in more detail below.
After any of the settings have been changed, they need to be saved by clicking on the “Save” button near
the bottom of the page. When doing that for the first time, you may be prompted for authorization to make
the changes. You can enter “owner” as the user name. By default, the password is “default” (no quotes).
If you receive an error stating you are not authorized to make changes, make sure to click on the “LAN
Access” link in the top-right of the page.
To restore the settings which are currently active on the device, click on the “Reset” button. This will revert
any changes you have made to the page since the last save.
April 18, 2018 2
Onset EG4xxx Configuration Guide 1 OVERVIEW
Figure 1: Example of meter Installation-Settings Page
1.1 Potential Transformer (PT) Configuration
This section is used to inform the device of any potential-transformers (PTs) that may be installed. Usually,
no PTs are installed and the settings here can be left at the default value of “direct (no PT)”.
April 18, 2018 3
Onset EG4xxx Configuration Guide 1 OVERVIEW
1.2 Current Transformer (CT) Configuration
This section defines what kind of current-transformer (CT) is connected to each of the CT positions. A
blank entry indicates that no CT is connected. When a CT is connected to the device, simply select the
appropriate CT selection from the pull-down list for the position the CT is plugged into. For example, if a
100A 0.94” J&D split-core CT is plugged into CT position 2, click on the pull-down list for CT2 and select
“JD JS 24mm/0.94" 100A”.
The format of the CT drop-down option is “[MFG] [MODEL] [SIZE MM]/[SIZE IN] [AMPERAGE]”
[MFG] 2-letter manufacturer code (see table 1)
[MODEL] CT Model (see table 2)
[SIZE MM] Inner-diameter in millimeters
[SIZE IN] Inner-diameter in inches
[AMPERAGE] Amperage rating of CT (not breaker amperage)
MFG code Manufactuer
JD J&D
CC Continental Control Systems
ML Magnelab
AE AccuEnergy
CR CR Magnetics
Table 1: CT manufacturer code description
MODEL Description
JS Split-core CT
JRFS Rogowski coil (rope CT)
ACT High accuracy split-core CT
SCT Split-core CT
RCT Rogowski coil (rope CT)
CR Solid-core DC CT
CRS Split-core DC CT
Table 2: CT model description
A multiplicative scale can be applied to the CT reading by entering a positive number greater than 0 to the
box right of the CT pull-down option. This is generally used if a single CT is measuring one set of parallel
feeds of the same phase.
WARNING: in many cases, parallel feeds are not perfectly balanced, and could have significant differences.
Because of this, we suggest monitoring each conductor, either by using a CT for each individual conductor,
or by using larger diameter CTs to encompass multiple parallel feeds (of the same phase).
1.2.1 High-gain mode
Available on EG4xxx models, High-gain mode amplifies the signal to the meter CT ports by 10 times. This
allows, for example, a 100A CT to act as a 10A CT. High-gain mode affects all CT inputs. Note, selecting
high-gain mode immediately changes the CT drop-down option to its respective lower amperage-rated
value. For example, enabling high-gain mode with a 100A CT will change the drop-down option to indicate
a 10A CT. Likewise, a CT configured for 75A will appear as a 7.5A CT.
April 18, 2018 4
Onset EG4xxx Configuration Guide 1 OVERVIEW
1.2.2 Rope CTs (Rogowski Coils)
Self-powered rope CTs are wired directly to the meter with a green 2-pin power plug. Rope CTs are
excellent for bus-bars and large switch-gear applications. Self-powered rope CTs are flexible and easy to
install but will not be accurate at low amperages. Rope CTs are configured like split-core CTs. For example,
the 4“ AccuEnergy 106mm rope should be configured as AE RCT 106mm/4.17" 2775A.
Rope CTs should not be used to monitor solar arrays, as solar uses a large range of amperages, often
insufficient for accurate monitoring with rope CTs when the inverter is in standby.
1.3 Remote Devices
EG4xxx can read data from Modbus TCP and RTU. For remote device configuration assistance, please
contact Onset support.
1.4 Register Configuration
This section defines what data gets recorded in the internal database of the meter. Each register has a
unique name that identifies what it is recording.
1.4.1 Register Name
Register names may contain any ASCII/UTF-8 characters except for control characters. With English characters, register-names can be up to 31 characters long.
1.4.2 Register Type
Each register can be configured to record one of several types of data. The type can be selected from the
drop-down menu to the right of a register-name. In our example, the drop-down menu looks as follows:
The entries in this popup-menu have the following meaning:
P: Records the power calculated from one or more current/voltage-pairs.
I: Records the RMS current measured by one of the connected CTs.
Idc: Records the DC (mean) current measured by one of the connected CTs.
April 18, 2018 5
Onset EG4xxx Configuration Guide 1 OVERVIEW
V: Records the RMS voltage measured by one of the connected line voltages.
Vdc: Records the DC (mean) voltage measured by one of the connect CTs.
F: Records the frequency measured on one of the channel inputs (CTs or voltage lines).
#: This is a special debug register.
=: Formula register. Records the value obtained by evaluating the specified formula. See Sec-
tion 1.4.4 for details.
In the example of Figure 1, we see five rows in the Registers section: the first two calculate power (P).
We will discuss those in more detail in the next section.
The third row is a register that records the current (I) of CT1, and the fourth records the voltage (V) of line
voltage input L1. Lastly the fifth register records frequency (F) of line voltage input L1.
A register can be added by clicking on the “Add Register” button. An existing register can be deleted by
clicking on the remove icon to the right of the register name.
1.4.3 Recording Power
There are two parts to configuring a register to record power: first, the subtype(s) to be recorded need to be
selected, second, the power-components that should be used to calculate the power need to be specified.
Power Subtypes The subtypes to record for a power register are selected by clicking on the subtypeselector button to the right of the register-type button. This will pop up the dialog shown below:
As shown here, there are five subtypes which can be recorded by turning on the corresponding checkbox:
= (net): Checking this box ensures that the net flow of power is available as a register-value. The
value of such a register increases when the calculated real power is positive and decreases
when it is negative. This is equivalent to a utility’s net-meter, for example.
+ (positive-only): Checking this box ensures that a register-value is available that increases only
when the calculated real power is positive. When the real power is negative, the registervalue does not change. This can be used, for example, to record only the power generated
by an inverter or only the power consumed from the utility.
- (negative-only): Checking this box ensures that a register-value is available that increases only
when the calculated real power is negative. When the real power is positive, the registervalue does not change. This can be used, for example, to record only the power consumed
by an inverter when there is no sun or only the power fed back into the grid.
April 18, 2018 6
Onset EG4xxx Configuration Guide 1 OVERVIEW
| (absolute): Checking this box ensures that a register-value is available that counts indepen-
dent of the sign of the calculated real power. That is, the register-value increases by the
absolute value of the real power regardless of whether it is positive or negative. This is not
often used.
(apparent): Checking this box ensures that apparent power is recorded in a register. Apparent
*
power is the sum of the product of the RMS voltage and current of each power-component.
As such, apparent power always has a non-negative value. This can be used, for example,
to track the quality of the power as the ratio of apparent power and absolute real power is
the power-factor.
When you are done selecting subtypes, click on the OK button to save the selection or on the Cancel button
to revert to the previously existing configuration.
Power Components The power components define which currents and voltages are to be combined to calculate a register’s power figure. In our example, the power components for the Main Panel (3 phase)
and Subpanel (single phase) registers look as follows:
This shows that Main Service (3 phase) power is calculated as the product of the current measured
by CT1 and the voltage measured on line L1 (e.g., black leg) plus the current measured by CT2 and the
voltage measured on line L2 (e.g., red leg), plus the current measured by CT3 and the voltage measured
on line L3 (e.g., blue leg).
The Subpanel (single phase) power is calculated from CT4 on L1, plus CT5 on L2.
To add a new power-component to a register, click on the “Add Component” button. To delete a component, click on the remove icon to the right of the component.
1.4.4 Formula Registers
Formula registers are a powerful tool to record quantities that can be derived from other, directly-measured
registers. For example register Main Panel measures the real power used at a site, then register Main
Panel*would measure the apparent power used at the same site. To record the power-factor for the site,
we would have to divide Main Service by Main Service*and take the absolute value. This can be
accomplished by defining a formula register as shown below:
In this example, we named the register “Main Panel Power Factor” and selected the equal-sign (formularegister) as the register type (see Section 1.4.2). We set the unit type as ”number with 3 decimals”. Finally,
we entered a formula of abs($"Main Panel"/$"Main Panel∗") for calculating the value of the register. Here, $"regname" is used to obtain the current (second-by-second) value of register regname, so
$"Main Service" will evaluate to the current site-usage (in Watts) and $"Main Service∗" evaluates
April 18, 2018 7
Onset EG4xxx Configuration Guide 1 OVERVIEW
to the apparent power used by the site. The abs() function calculates the absolute value of the value
passed to it (i.e., it’s always positive).
An online-version of the function-list can be found in the Help section of the meter web-pages.
Several caveats apply to using formula registers:
• Do not reference a formula register from another formula register. The result can be unpredictable.
• Calculating formulas takes time. Do not overload the meter with unnecessary formula registers.
• All calculations are performed using single-precision IEEE-754 floating-point numbers. The final value
of a formula register is then rounded to a 64-bit signed integer number.
1.5 Totals and Virtual Registers Configuration
Virtual registers are calculated as a sum or difference of real (physical) registers. Virtual registers to not take
up any space, and a virtual register can be added and removed in the same manner as physical registers.
A register is added by clicking on the Add Register button. A register can be removed by clicking on the
remove icon to the right of the register drop-down menu. You can select whether there register should
be added to or subtracted from the virtual registers value by selecting + or - from the drop-down menu to
the left of the register name, respectively.
Each power register will show up in several variations in the menu, namely with one variant for each selected
subtype (see “Power Subtypes” in section 1.4.3 Recording Power). Positive-only registers end in a ’+’,
negative-only registers end in a ’-’, absolute-registers end in a ’|’, and apparent power registers end in a
’*’. Net registers do not have an appended symbol and just appear as the register name.
In the image below, Register 1 has net, positive-only, and apparent power subtypes selected, so the
virtual register has choices for net, positive-only, negative-only, apparent power, and absolute (negativeonly and absolute are calculated on-the-fly because both ’net’ and ’positive-only’ subtypes are chosen).
The menu also has entries of the form MAX(reg,0) and MIN(reg,0). Those are for backwards compatibility with configurations created by older firmware and should no longer be used.
April 18, 2018 8
Loading...