Vermont Energy Control Systems

User Manual


This document is intended to help with initial setup and use of the Vesta system Controller. It covers physical setup, electrical connections, and access to the built-in web interface. In addition to this document, there are additional companion documents:

  1. Rule Programming
  2. Graphical User Interface

Historical Note: The Vesta controller is an evolution of an earlier control system that was known as the 'NoFossil Control System'. As such, there may be references to 'NFCS' in the documentation or in other places. For all intents and purposes, 'NFCS' can be considered synonymous with 'Vesta'.

Disclaimer: This documentation (and web site) is under construction. Every effort is being made to ensure that it is accurate and complete. However, it is entirely possible that it may contain errors and omissions. If you see a problem, please contact Vermont Energy Control Systems.


There a a few requirements for Vesta installation:

  1. A dry and relatively clean location
  2. A 110Vac wall outlet to plug the power supply into
  3. A network connection (standard Cat5 cable)

The Vesta controller must be installed in a dry location that does not experience condensation and where temperatures do not exceed 140 degrees Fahrenheit. Since it has no fan and is in an enclosure dust is not a serious problem, although electrically conductive or corrosive dust should be avoided. It does not need to be physically near the equipment that is to be controlled, although it is desirable to choose a location that minimizes the length and installation effort of the cables between the Vesta controller and the equipment that is to be monitored and controlled.

Internet access is not required, although it's desirable. At a minimum, a crossover cable can be used to connect the Vesta controller directly to a computer. A computer with a web browser is needed to configure and program the Vesta controller. Once it's set up, network access is not necessary.

No tools are required. However, it's very helpful to label sensor cables and other wires as they're connected. A labelmaker or wire lables are strongly suggested.

Physical Setup

Unpack the controller and place it in a convenient clean and dry location. It may be mounted on any horizontal or vertical surface that's protected from water. Intially, only network and power connections are needed. Plug an Ethernet cable into the white connector on the right side. Make sure that the front panel power switch is in the Off (down) position, and connect the wall-mounted power supply. The connector is next to the power switch.

Turn on the power. If the Vesta controller is in its as-delivered configuration one of the green LEDs on the front panel should illuminate after about 30 seconds.

The Vesta controller has a pre-assigned IP address that should allow it to be visible on your network. This address (a number like is on the configuration sheet that is included with the controller. Start a web browser on your computer (Chrome, Internet Explorer, Firefox, Safari) and type the IP address of the Vesta controller into the URL bar. Press 'Enter' and the Vesta controller home page should appear. Depending on the browser, you may need to preface the IP address with 'http://' -, for instance.

Once you have the controller displayed on your browser, bookmark the address.

In this example, the IP address is and the display shows configuration details that may differ from unit to unit. If this does not work, refer to the next section for network configuration.

In almost all cases, all configuration and interaction with the Vesta controller is through a web interface. The Vesta controller has a built-in web server which provides access to the system.

As delivered, the Vesta controller is set up with minimal configured I/O. The home page displays current values for all configured inputs and outputs. Refreshing the home page will refesh the values as well. The home page does not have any security, since it provides only a passive view of system data.

All the other tabs require a username and a password. This is to prevent unauthorized changes to your system. The username and password are on the configuration sheet provided with the unit.

At this point, plugging a sensor into the first Sensor Input connector (right side, white connector group) should result in a display of the sensor's temperature. The pages in the web interface do not refresh automatically - you'll have to click the tab (or click reload on your browser) to display fresh data.

Along the right side of the front panel there are four LEDs and a small three-position switch. As delivered, the LEDs and switches are connected to Vesta discrete inputs and outputs. There are also some simple rules defined that illuminate LEDs based on switch position. Try moving the switch and observe what happens to the LEDs and to the Vesta controller web interface.

This switch and these LEDs can be used for any desired purpose. In particular, they are good for developing and testing rules before assigning the rule to real hardware.

Clicking the 'System' tab on the web interface brings up a page where some basic system settings can be configured. Each section of this page will be covered in detail later in this manual. For initial setup, the most important setting is the 'Centigrade' checkbox. While the system can be switched between Centigrade and Farenheight at any time, any numeric values used in rules will NOT be converted and will have to be manually re-entered in the new units. For instance, if the system was originally programmed in Farenheight and there was a rule to turn on a circulator any time room temperature dropped below 70 degrees, the rule would have dramatically different effects if the system were then changed to Centigrade. 70°C is a pretty high room temperature! It's important to choose units at initial setup.

Make any changes and click 'Update'. Changes take effect immediately.

Networking and the Vesta Controller

While the Vesta controller does not require Internet access to function, it is helpful for several reasons:

  • Setting and maintaining the accuracy of the system clock
  • Reporting network data to enable the 'Get Ip Address' function on the VECS web site
  • Uploading and installing updates
  • Enabling external access (so that you can view system performance from your cell phone, for instance)
  • Enabling remote troubleshooting and support

If it's at all possible, Internet access is preferred. Usually this is as simple as installing a standard Ethernet cable from your Cable/DSL modem or router to the Vesta controller.

Network Considerations

In most cases, the Vesta controller is preconfigured for your network before delivery. To connect with it, simply plug it in, turn it on, and type its IP address into the URL bar of your favorite web browser (Chrome, Firefox, Safari, Internet Explorer...). The default IP address for most networks is 192.168.18, but it may be different in your situtation. Look on the configuration sheet included with your controller.

If you can't connect to the Vesta controller web interface home page, check the network troubleshooting section.

Minimal Network Requirements

In order to program the Vesta controller or view any data, you must at a minimum have a computer networked to the controller. This can be accomplished with a crossover cable as described in the section on configuring your PC to access the Vesta controller.

Sensor Types

There are three commonly used sensor types for the Vesta controller - general-purpose TS-1058 temperature sensors, TS-1060 thermocouples, and TS-1061 thermistor sensors. There are many other types, but these cover most applications. They are electrically quite different, but the Vesta controller can accomodate any sensor type on any channel.

The TS-1058 sensors work over a range from about -20°F to 212°F. They are inexpensive and in the Vesta controller they provide a temperature resolution of better than a tenth of a degree Centigrade.

The TS-1060 sensors are standard type K thermocouples. They require an external amplifier (part number TCA-1125). They can measure temperatures from 32°F to about 2500°F.

As configured for the Vesta controller, the TS-1061 sensors cover the range from about 40°F to over 300°F (limited by melting of the cable insulation). Because thermistors are highly nonlinear, they provide much better resolution at lower temperatures. At room temperature their resolution is better than a tenth of a degree, but at boiling the resolution is only about a quarter of a degree Centigrade. They are smaller than the TS-1058 sensors and can fit in tight spaces.

Connecting Sensors

The Vesta can accomodate a total of 16 sensors. Sensors use telephone-style (RJ11) connectors. On the Vesta controller, sensor connections are grouped into four rows with four connectors on each row. Sensors may be plugged directly into these connectors.

There is also a fifth connector on each row. This is a standard Ethernet style (RJ45) connector that allows use of a sensor breakout box. A breakout box can be used if you have a group of sensors at a remote location - in a nearby building, or on the roof, for instance. Rather than running four long individual sensor cables to the remote location, you can run a single Ethernet-style cable to the remote location, and then use a sensor breakot box to connect the individual sensors. For each row of four sensors on the Vesta, either the individual connectors OR the breakout box may be used - not both.

Physical I/O Tab

Sensors are configured using the 'Physical I/O' tab on the Vesta controller web interface. This tab displays all of the possible inputs and outputs for the Vesta controller, and allows you to specify which inputs and outputs you will use in your application. Sensor inputs are identified as Analog Inputs on this page.

Because there are so many inputs and outputs, the Vesta controller allows you to specify which ones you're going to use. Only selected inputs and outputs are visible outside the 'Physical I/O' page. In the Vesta controller, the process of selecting a physical I/O involves three steps:

  1. Identify connector number on the outside of the controller where your sensor or other device is plugged in. For instance, the sensor inputs are on top right side of the Vesta controller and labeled with channel numbers from 1 to 16 (by default - different models may have different numbers of inputs).
  2. Find the corresponding line in the 'Physical I/O' page. In our example, the first line on the 'Physical I/O' page corresponds to Analof Input 1. To use a physical I/O in the Vesta controller, you must select it by clicking the 'Create Element' link in the rightmost column of the 'Physical I/O' page. In this example, an element has already been created and assigned the name 'Analog Input 1'.
  3. For each sensor, make sure that the correct sensor type is selected. The most commonly used sensor in the Vesta controller is the TS-1058.
  4. Finally, go to the 'Data Elements' tab and give your sensor a meaningful name.

As each sensor is added, check to see that a reasonable temperature is displayed. Holding the sensor between your fingers should result in a quick rise in displayed temperature.


The Vesta controller allows calibration of both gain and offset for each sensor. In most cases, calibration is not necessary. If calibration is desired, an offset calibration is usually all that's needed. Offsets are simply added to the measured temperature.

To get the highest possible accuracy, gain calibration can be done as well. To perform gain calibration, you need to establish two known temperatures that are as far apart as possible while remaining within the sensor's measurement range. The easiest way to do this is to use an ice bath and boiling water. Immerse the sensors in an agitated (stirred) bath of water packed with crushed ice. This will be very close to 0°C (32°F). Water at a vigorous boil will be very close to 100°C (212°F). If you're at a high altitude, you'll have to correct for altitude effects.

Download the sensor calibration spreadsheet. Follow the instructions in the spreadsheet - enter the actual low and high temperatures (use a reference thermometer if you have one, otherwise use freezing and boiling). Enter the actual readings for each sensor at low and high temperatures. The blue cells in the spreadsheet will then give you the values for gain and offset for each sensor. Enter those values in the Physical I/O tab.


Relay theory is beyond the scope of this manual. There is a how-to document on this site, and there are many online explanations such as this one: Relays are key components of most electrical control systems, and the Vesta controller is designed to operate up to 32 relays.

Relays are typically used for two purposes:

  1. Control - To allow the Vesta controller to control some external device such as a valve or a circulator
  2. Sense - To allow the Vesta controller to sense the presence of electrical power that's provided by some other means, such as another controller. For instance, a relay could be used to detect that an oil boiler was running.

Control relays have 12Vdc coils and are directly controlled by the Vesta controller. Each control relay is driven by a discrete output.

Sense relays have coils that match the voltage that needs to be sensed. For instance, a relay that's used to sense whether a 120Vac pump is running would use a 120Vac coil wiried in parallel with the pump motor. The relay contacts would in turn be connected to a Vesta discrete input.

Control Relays

the Vesta controller discrete outputs can drive any relay that has a DC coil that operates at 12 Volts and draws less than 200ma of coil current. This includes virtually all 12Vdc relays. The 'standard' Vesta control relay is the Schrack PT270012, which has a coil current of about 65ma and can control loads up to 10 amps.

Relays come in many contact configurations and mounting styles. The Schrack PT270012 is designed to plug into a socket which in turn can be mounted on a standard DIN rail. The Schrack PT270012 has double pole / double throw (DPDT) contacts rated for 12 amps of current. It also has a window on the top which shows an orange flag if the relay is activated as well as a lever to manually actuate the relay. These features can help with troubleshooting.

External Relay Enclosure (RM-1206)

It is desirable to keep high voltages outside of the Vesta controller enclosure for three reasons:

  1. To avoid accidentally vaporizing expensive circuit boards
  2. To keep the Vesta controller enclosure intrinsically safe and finger-friendly
  3. To reduce the distance that power has to travel to get to the high voltage loads

To achieve these goals, the preferred approach to controlling high voltage loads is to us a relay enclosure that is mounted near the loads and controlled by the Vesta controller. This relay enclosure can contain any combination of control and sense relays. The most common use of external relays is typically control, so the standard external relay enclosure is set up with control relays.

Since each discrete output connector on the Vesta controller carries four channels, the logical capacity of an external relay box is four relays.

Accordingly, the RM-1206 Relay Module contains four relays. It has an RJ45 connector for connecting to Vesta discrete outputs. Internally, each relay has two electrically separate sets of contacts, each with common (C), Normally Open (NO), and normally Closed (NC) contacts. These are brought out to screw termminals for easy connection to electrical devices.


The RM-1206 is connected to any Discrete Output connector on the Vesta Controller using standard Cat5 Ethernet cable. The Vesta color code for discrete outputs is blue, so a blue cable is suggested.

The screw terminals in the relay module can accomodate up to 12 gauge stranded and 14 gauge solid wire if necessary, but smaller gauges are much easier to accomodate in the limited internal space.

As with all high voltage wiring, ensure that all relevant codes are followed.

WARNING: To avoid damage to the Vesta controller, disconnect the Vesta controller cable from the relay box before doing any wiring.

Sample External Control Relay Application

In this example, the Vesta controller controls a 120Vac circulator. The 120Vac neutral goes directly to the circulator motor. The 120Vac 'hot' goes to one of the 'Common' terminals on a relay, The corresponding 'Normally Open' (NO) terminal is connected to the circulator motor. The relay coil is connected to an Vesta discrete output.

When the Vesta controller discrete output is asserted (set to 'TRUE'), the relay coil will be energized. That will change the relay contacts so that 'common' is connected to 'NO'. That will allow current to flow through the circulator motor.

Many variations are possible. If the circulator motor were connected to the NC terminal instead, then the circulator would run whenever the relay was NOT activated. Each relay has a second pair of contacts which could be used to switch a completely different load or perhaps a status LED.

The Variable Speed Control Unit is typically mounted next to the device that's being controlled in order to keep high voltage wire lengths to a minimum. There is a light gauge cable connecting the Variable Speed Control unit to the Variable Speed Breakout Box that's typically mounted next to the Vesta controller. This cable uses a standard RJ11 connector on the Vesta controller end and is hard-wired to the control unit. The example photos here are for a benchtop demo and use standard appliance line cord for the high voltage (115vac) wiring. Actual installations would typically use armored BX cable or a code-compliant equivalent.

Configuring the Control Unit

Dip Switches

The heart of the Control Unit is the 'Nimbus' manufactured by Control Resources. In the Vesta controller application, it's configured to be controlled by a 4-20ma signal. The DIP switches should be set according to the picture at the right - switches 1,2 and 7 on and the rest off.


There's also a jumper which needs to be installed on the two pins nearest the edge of the card. This photo is courtesy of Smokeless Heat in Pennsylvania. They use the Vesta controller with an interesting Swedish boiler, and have quite a bit of experience with the Nimbus variable speed controller.

The Nimbus is a quite sophisticated device. There is a complete manual available from Control Resources.

Connecting Power and Load

The Control Unit requires connection to both 115vac and the load that is to be controlled. These connections are made as shown in the photo below, The load is to the left and is connected to the red and black wires at the left end of the row of wires (when viewed as shown). The next two wires (black and white) are connected to 115vac power.

Connecting the Control Signal

The last connection that's required is the control signal from the Variable Speed Breakout Box. This signal will be provided via an RJ11 cable (typically flat 4 conductor). If the standard 4 conductor color code is used, the signal is on black and yellow, corresponding to pins 1 and 4. If six conductor cable is used, the control is on pins 2 and 5.

The black wire (pin 1) is connected to the purple wire on the control unit, and the yellow wire (pin 4) is connected to the gray wire. Because the signal wires are so small, use cable ties to tie the signal wires to the control unit wires as shown.

This section is intended to clarify terminology that will be used in the rest of the document.


I/O: Input and Output
Discrete An electrical input or output which can be in one of only two states, generally corresponding to 'on or 'off'.
Analog An electrical input or output which can have a wide range values. Analog inputs are typically used to measure values such as temperature.


The Vesta controller is at its core a computer, and it processes rules as a computer does. In the physical world, a pump may be on or a contact may be closed or a coil may be energized. Inside a computer, these states have to be represented as TRUE or FALSE values. the Vesta controller uses TRUE and FALSE in the following ways:

TRUE means 'on' or 'non-zero' or 'active'. The implication is that something is happening.

  • For contacts, TRUE means 'closed'.
  • When a discrete output is TRUE, power is being supplied to the relay coil, LED, or whatever the discrete output is driving.
  • For a timer or any numeric value, TRUE means non-zero.

FALSE means 'off' or 'zero' or 'inactive'.

  • For contacts, FALSE means 'open' - no current is flowing.
  • When a discrete output is FALSE, no power is being supplied.
  • For timers and numeric values, FALSE means zero.

TRUE and FALSE are not typically used with temperatures or other values that can have a fractional part, because the results can be unexpected. A temperature of 0.001 degress will display as '0', but is actually non-zero and will be treated as TRUE.

Electrical Connection and Signal Types

the Vesta controller is designed to connect electrically to a variety of physical devices. Electrical connections are divided into four broad categories:

  1. Power. Electrical power to run or operate a device.
  2. Communication. Etherenet, USB, or other connections used to transmit data between intelligent devices.
  3. Analog. Electrical signals that can have a range of values. The output of a typical temperature sensor would be an example.
  4. Discrete. Electrical signals that can have only two values such as off/on, open/closed, or active/inactive. Also called digital signals.

The Vesta controller uses all four categories. Power is straightforward, and communication is usually only the Ethernet connection. The bulk of the connections (and complexity) are the analog and discrete signals.the Vesta controller supports both inputs and outputs for these types of signals. They're typically used as follows:

Analog Inputs are to read temperature and other types of sensors that can measure a range of values.

Analog Outputs provide a signal that can be used to drive certain pumps, fans, or valves to variable speeds or positions.

Discrete Inputs are typically used to detect contact closure. Each discrete input consists of a pair of wires. If the input wires are shorted together, the input is sensed as 'TRUE'.

Discrete Outputs provide the ability to turn on or activate an external device such as a relay or an LED. A discrete output that's on provides 12 Volts.

All programming and control of the Vesta controller is accomplished through the use of these four electrical signal types.


For external connectors, colors are used where possible to help minimize the chances of plugging the wrong cable into the wrong connector. Each signal type has a unique color as follows:

  • Analog Inputs are grey (or white)
  • Analog Outputs are yellow
  • Discrete Inputs are green
  • Discrete Outputs are blue

These colors are also used in the web interface when displaying values for discrete inputs and outputs. While it's not required, using matching cables will help prevent mistakes.

Inside the controller, red is +5V, yellow is +12V, and black is ground. There are some exceptions, but this convention is used where possible.


RJ45: The Vesta controller uses standard RJ45 connectors for some of the I/O. These are 8 conductor connectors that are used for Ethernet cables. The male connector is easily crimped onto standard Ethernet cable with an inexpensive tool. The female connector is designed to snap into a panel (such as a wall plate) and is known as a 'keystone' connector. Electrical connection to the female connector is accomplished by pressing wires into slots in the back of the connector with another inexpensive device called a 'punchdown' tool.

RJ11 and RJ12: These are the connectors that are often used for telephone cables. They have positions for six conductors, but often only four are used. They look identical to RJ45 connectors, except that they are narrower.

A connector that uses all six conductors is called RJ12, while a connector that only uses the middle four conductors is called RJ11.