Hardware Manual for the SiteMonitor System
This manual covers the SiteMonitor Base 3 and all compatible expansion modules.
This manual only covers the hardware portion of the system. The firmware is covered in a separate manual.
Warning
As of August 24, 2025, this documentation is still a work in progress and was based on earlier documentation which has not been fully updated. If you find something that seems weird or missing, please let us know at custsvc@packetflux.com
Physical Mounting
SiteMonitor Products are designed to mount either to the Wall or to a DIN rail. We recommend DIN rail mounting wherever possible. The plastic clip included with the products is needed for both DIN rail and wall mounting.
The cabling included with the expansion units is based on mounting the Base unit at one end, and then all of the expansion units to one side of the base unit, with the large flat sides touching. If you do not mount in this fashion, the enclosed cabling will likely not reach.
Wall Mounting
For wall mounting, screw the plastic bracket to a suitable surface, ensuring multiple brackets are spaced far enough apart that the units can mount side by side. Snap the SiteMonitor unit onto the bracket. To release a previously mounted unit, grab the top and bottom of the mounted unit and pull while twisting the unit either upward or downward.
DIN Rail Mounting (Recommended)
For DIN rail mounting, mount the DIN rail in a suitable fashion, and then snap the plastic bracket onto the rail, and the SiteMonitor unit onto the bracket. To release the unit from the rail, reach behind the unit and pull forward on an exposed tab of the DIN rail mounting bracket. This will be easier if you pull on the tab which has a "springy U shape" built into the bracket.
Cabling the Expansion Bus
Note
This section is only relevant if you are using expansion modules in your SiteMonitor System.
Warning
It is important that the Expansion Bus connectors are never inserted or removed with the power on. Failure to heed this warning may cause damage to the base unit or one or more of the expansion modules.
Note that this is less critical in later editions of the Base Unit, but it is still a good practice.
For the first expansion unit, connect the supplied 6p6c cable from the expansion port on the base unit to the expansion port on the expansion unit. For additional expansion units, repeat the process, connecting each expansion unit to the previous expansion unit.
There is no difference between the expansion ports on the expansion units. As a result, you can connect either port in whichever manner is easiest. We find that connecting directly adjacent ports tends to be neater. All that matters is that there is a continuous chain from the first to the last unit.
If you need to use a longer cable than the provided expansion cable, you can use any 6p6c phone cable, either straight or reversed. In order to prevent damage to the units, it is important to ensure that all 6 pins are connected, either straight through (pin 1 to pin 1, pin 2 to pin 2, and so on), or reversed (pin 1 to pin 6, pin 2 to pin 5, and so on).
The expansion bus is designed to only traverse a few dozen feet, so please keep all cables as short as possible.
Powering the Base3 via Direct DC
For many SiteMonitor systems, all power for the Base and Expansion modules is obtained from the base unit. As a result, the power requirements for a complete system will vary.
The SiteMonitor Base 3 can operate on the voltages typically found in a 12, 24 or 48V battery system, with an absolute maximum voltage of 60V. All modern expansion modules support 48V operation as well.
The Base3 has additional circuitry which permits operation from -24V and -48V.
Warning
Very early SiteMonitor modules (prior to revision H) had a much lower maximum voltage rating. As these modules are not supported by the Base3, if you have these devices in your system, please do not attempt to attach them to the Base3.
Note that the serial numbers on these devices were 32767 or earlier.
On the lower end, all devices are best powered off of a 12V or higher system. The units will operate slightly below 12V, but will start to drop off for low voltage around 9-10V.
The amount of current needed for the SiteMonitor System will vary depending on the voltage provided to the unit. Higher supply voltages will generally result in lower current draw - but will also generally result in higher power consumption since some SiteMonitor components use the same current regardless of voltage.
Almost all smaller SiteMonitor systems (up to a few expansion modules) will operate off of a 12V power supply at 1A, or a 24V or 48V power supply at 0.5A. Most need even less than that – with 1 Watt being the typical consumption of a SiteMonitor Base unit and a couple of expansion modules.
When powering from a source capable of providing more than 2 Amps, an external fuse is REQUIRED. The fuse should typically be 1A fast blow unless a lot of modules have been added to the system.
On the SiteMonitor base unit, there are two power inputs labeled as "VinA" and "VinB". Either or both of these inputs can be used to power the SiteMonitor unit. If both are connected, the SiteMonitor will draw power from the input with the highest voltage.
For each of the Vin inputs there is a corresponding connection labeled "Rtn", which is short for "Return". The SiteMonitor system ties these together internally. As a result, you should ensure that if your power sources share a common connection, such as ground, that the common side of each supply is connected to Rtn.
For a +12, +24 or +48VDC source, the positive power output should be connected to the Vin pin and the grounded/negative side should be connected to Rtn.
For a -24 or -48VDC source, the negative output should be connected to the Vin pin and the grounded/negative side should be connected to Rtn.
When operating at a site with both commercial and conditioned (UPS) power, we recommend connecting the SiteMonitor to two power sources. Typically one which is derived directly from the commercial power, and one which is derived from the UPS power. This will permit two things. The first is the monitoring of commercial power availability separately from the UPS power. The second is permitting remote control of the conditioned power source without affecting the SiteMonitor availability. Our customers often use a salvaged 12 or 24VDC "wall transformer" for this purpose.
When operating at a site with a battery system, we realize that only one power source is often available. As a result, we expect that many solar sites will only use one of the two power inputs. There is minimal benefit to connecting both power connections to the same source.
We do not recommend connecting one of the power inputs directly to solar cells or a similar "unregulated" source, as the open-circuit voltage across a typical solar array will often exceed the maximum rating of the SiteMonitor system causing damage. In addition, many charge controllers expect the solar array to be isolated from the rest of the system, and the Base Unit will cause this isolation to be broken.
In addition, it is important to ensure that any source connected to the power inputs is capable of providing sufficient current to power the unit. That is, don't try to use the unused power input as a spare "voltmeter input" unless you remove the jumper as described in a future section.
When connecting the power, it is important to observe proper polarity. In addition, it is important to understand that the negative on both inputs is electrically connected internally. Or stated differently, there is a wire internal to the SiteMonitor which connects the Rtn pin of VinA with the Rtn pin of VinB. If power is connected incorrectly, you can damage the SiteMonitor simply by causing a short through this internal connection. As a result, we recommend verifying proper connection and polarity with a voltmeter before plugging the removable terminal strip into the unit.
To connect power, simply attach the power to the appropriate screw terminals, and attach to the unit (if the screw terminal block was removed to simplify connections).
Powering the Base3 via PoE
The Base3 will also accept passive PoE via spare pairs on the Ethernet Input.
The 4,5 and 7,8 pairs are used for this power. Either the 4,5 or the 7,8 pair can be positive and the remaining pair can be negative.
The PoE source must be 12, 24 or 48VDC negative ground. That is, +48VDC, not -48VDC.
Utilizing the DC power inputs as voltmeters and not as voltage sources
There is a pair of jumpers internal to the Base3 which will permit one or both of the Vin inputs to be used as a voltage source instead of a power input.
With the appropriate jumper set to the default position of "PWR", it is important to ensure that the source is capable of powering the unit. When it is set to "MTR", the ability for that input to act as a power source is disconnected and the input is able to measure from -60V to +60V in respect to the Rtn terminal.
Connecting the Network
To physically connect the SiteMonitor to an Ethernet network, simply use a standard CAT5 cable to connect the Ethernet Port to an Ethernet Switch.
The Ethernet Port autonegotiates up to 100Mb/s and can handle either full or half duplex.
Additional Base Unit Connections
The 12 position terminal block has the following pinout:
Note: Pin 1 is the position closest to the Ethernet and 6p6c Jacks.
| Pin | Function |
|---|---|
| 1 | Relay Common |
| 2 | Relay Normally Open |
| 3 | Relay Normally Closed |
| 4 | Not used |
| 5 | Resistance Input |
| 6 | Resistance Common |
| 7 | Shunt Monitoring Input + |
| 8 | Shunt Monitoring Input - |
| 9 | Voltage Input A |
| 10 | Voltage Return |
| 11 | Voltage Input B |
| 12 | Voltage Return |
Relay Output (Pins 1, 2 and 3)
The Base unit includes a built-in Single Pole Dual Throw (SPDT) relay.
This relay is capable of switching loads which do not exceed 2A or 60W. This means that under 30V, you are limited to 2A, and above 30V you are limited to 60W loads.
Exceeding the switching capability of this relay will result in permanent damage to the relay and will necessitate non-warranty repair of the unit.
Pin 1 is the common terminal on the relay, and will need to be connected if the relay is to be used. The remaining two relay pins (2 and 3) will need to be connected depending on your application.
Pin 2 is the Normally Open contact. This contact will never be connected to the common terminal (pin 1) unless a command to activate the relay is received.
Pin 3 is the Normally Closed contact. This contact will always be connected to the common terminal (pin 1), unless a command to activate the relay is received.
When power is lost to the unit, the relay will revert back to it's default state (connecting pin 1 and 3). As a result, we encourage users of the SiteMonitor system to pick the contacts based on what state is desired when the power is off, or recently restored.
Resistance Sensing Input (Pins 5 and 6)
Pins 5 and 7 form a resistance sensing input, which can be read remotely.
The intent of this input is to read either a resistance-based sensor (fuel level, temperure) or a relay or switch closure (security loop or alarm closure) from an external device.
Warning
This input is not isolated internally and as such, care must be taken to ensure that voltage is not applied to either of the closure input pins. Applying voltage to either pin may cause damage and will likely result in a non-warranty repair, and may result in a potentially hazardous situation.
To use this input, simply connect the resistance or switch closure to be read between pins 4 and 5.
Current Shunt Input (Pins 6 and 7)
This input is designed to accept an analog voltage input from a shunt or other similar device which has a maximum output voltage of no more than +-100mV (aka+-1/10th of a volt). Care must be taken to ensure that this voltage is not exceeded.
On positive voltage sources (for example +48VDC), this input supports high or low side shunt inputs, with high side shunts preferred.
On negative voltage sources (-48VDC), the shunt must be installed in the grounded (low) lead to avoid exceeding the common mode voltage range of this input.
Warning
This is a non-isolated input. Be careful of what you attach it to.
Power Source Inputs (Pins 9, 10, 11 and 12)
The SiteMonitor Base Unit (and all daisy chained units which do not have separate power inputs) receive their operating power through these inputs. The unit has been designed to be connected to up to two separate sources of power, so that it will still operate when one of the two sources is unavailable. In addition, the voltage of each of these inputs can be read remotely.
Details on how to connect to these inputs have been covered in a previous section.
Internal Temperature Sensor
The Base Unit also has an internal temperature sensor. It reads in 0.1 degrees Celsius increments and is visible through the Web Interface and SNMP.
Expansion Module Details
We are aware that not all expansion modules are covered below. We are in the process of updating this documentation to cover moe of the modules.
4 Channel Relay Output Module
This module adds four relays to the SiteMonitor System. Each relay is capable of switching the lower of 2A or 60W. That is, below 30V, the limit is 2A. Above 30V, the limit is 60W.
The 12 position terminal block has the following pinout: Note: Pin 1 is the position closest to the 6p6c Jacks.
| Pin | Function |
|---|---|
| 1 | Relay #1 Common |
| 2 | Relay #1 Normally Open |
| 3 | Relay #1 Normally Closed |
| 4 | Relay #2 Common |
| 5 | Relay #2 Normally Open |
| 6 | Relay #2 Normally Closed |
| 7 | Relay #3 Common |
| 8 | Relay #3 Normally Open |
| 9 | Relay #3 Normally Closed |
| 10 | Relay #4 Common |
| 11 | Relay #4 Normally Open |
| 12 | Relay #4 Normally Closed |
The Common terminal of each relay will need to be connected if the relay is to be used. The remaining two relay pins will need to be connected depending on your application.
The Normally Open contact will never be connected to the common terminal unless a command to activate the relay is received.
The Normally Closed contact will always be connected to the common terminal unless a command to activate the relay is received.
When power is lost to the unit, the relay will revert back to it's default state. As a result, we encourage users of the SiteMonitor system to pick the contacts based on what state is desired when the power is off, or recently restored.
6 Channel Switch Input
This module adds six switch inputs to the SiteMonitor System. Each input can be used to monitor a relay or switch closure from an external device. For example, a security loop or status output on a device.
The 12 position terminal block has the following pinout: Note: Pin 1 is the position closest to the 6p6c Jacks.
| Pin | Function |
|---|---|
| 1 | Switch #1 Input |
| 2 | Switch #1 Common |
| 3 | Switch #2 Input |
| 4 | Switch #2 Common |
| 5 | Switch #3 Input |
| 6 | Switch #3 Common |
| 7 | Switch #4 Input |
| 8 | Switch #4 Common |
| 9 | Switch #5 Input |
| 10 | Switch #5 Common |
| 11 | Switch #6 Input |
| 12 | Switch #6 Common |
To use this input, simply connect the switch to be read between pins 4 and 5. A common application for this input is as a security loop. That is, one or more normally closed security sensors, such as a door sensor, or a loop of wire placed strategically through a solar panel such that it has to be cut to be removed, are connected in series to these inputs. In this way, notification can be received when a security event occurs.
This input is not isolated internally and as such, care must be taken to ensure that voltage is not applied to either of the closure input pins. Applying voltage to either pin may cause damage and will likely result in a non-warranty repair, and may result in a potentially hazardous situation.
2 Relay Output / 3 Switch Input Module
This module adds two relays and three switch inputs to the SiteMonitor System. Each Input and Output is identical in function to those found in the 4 Relay Output or 6 Switch Input Module. As such, you should consult that portion of this documentation for information about each type of input.
The 12 position terminal block has the following pinout: Note: Pin 1 is the position closest to the 6p6c Jacks.
| Pin | Function |
|---|---|
| 1 | Relay #1 Common |
| 2 | Relay #1 Normally Open |
| 3 | Relay #1 Normally Closed |
| 4 | Relay #2 Common |
| 5 | Relay #2 Normally Open |
| 6 | Relay #2 Normally Closed |
| 7 | Switch #1 Input |
| 8 | Switch #1 Common |
| 9 | Switch #2 Input |
| 10 | Switch #2 Common |
| 11 | Switch #3 Input |
| 12 | Switch #3 Common |
2 Shunt / 4 Voltmeter Input Module
This module adds two shunt and four voltmeter inputs to the SiteMonitor System.
The 12 position terminal block has the following pinout: Note: Pin 1 is the position closest to the 6p6c Jacks.
| Pin | Function |
|---|---|
| 1 | Shunt #1 Positive (+) Input |
| 2 | Shunt #1 Negative (-) Input |
| 3 | Shunt #2 Positive (+) Input |
| 4 | Shunt #2 Negative (-) Input |
| 5 | Voltmeter #1 Positive (+) Input |
| 6 | Voltmeter #1 Negative (-) Input |
| 7 | Voltmeter #2 Positive (+) Input |
| 8 | Voltmeter #2 Negative (-) Input |
| 9 | Voltmeter #3 Positive (+) Input |
| 10 | Voltmeter #3 Negative (-) Input |
| 11 | Voltmeter #4 Positive (+) Input |
| 12 | Voltmeter #4 Negative (-) Input |
The shunt inputs are designed to accept an analog voltage input from a shunt or other similar device which has a maximum output voltage of no more than +-100mV (aka+-1/10th of a volt). Care must be taken to ensure that this voltage is not exceeded.
Warning
This is a non-isolated input. Be careful of what you attach it to.
The voltmeter inputs are semi-isolated inputs designed to measure a voltage between 0 and 75V. The input circuit is designed to support reading of voltages above or below the common ground used to power the sitemonitor system. However, it is not designed to read voltages which must remain isolated from the common ground or return (as defined by the negative (-) voltage inputs on the base unit) as the inputs are only semi-isolated. In addition, it is not designed to measure voltages which are not referenced to this same common ground.
What this means in practice is that you can read a positive voltage by hooking the voltage source up to the input in a normal fashion – that is hook the + voltage up to the + input, and hook the – lead up to the negative input.
You can also read a negative voltage such as -48VDC by hooking up the voltage to the input in a ‘backwards’ fashion. That is, you hook the -48VDC power source up to the – input, and the return/common to the + input. This will result in a reading of 48V in the SiteMonitor system.
However, you cannot use these inputs to measure a voltage which is not referenced to the same return.
3 Shunt / 3 Voltmeter Input Module
This module adds three shunt and three voltmeter inputs to the SiteMonitor System. As the inputs are identical to those in the 2 Shunt / 4 Voltmeter module, that section of this manual should be consulted for information on using these inputs.
The 12 position terminal block has the following pinout: Note: Pin 1 is the position closest to the 6p6c Jacks.
| Pin | Function |
|---|---|
| 1 | Shunt #1 Positive (+) Input |
| 2 | Shunt #1 Negative (-) Input |
| 3 | Shunt #2 Positive (+) Input |
| 4 | Shunt #2 Negative (-) Input |
| 5 | Shunt #3 Positive (+) Input |
| 6 | Shunt #3 Negative (-) Input |
| 7 | Voltmeter #1 Positive (+) Input |
| 8 | Voltmeter #1 Negative (-) Input |
| 9 | Voltmeter #2 Positive (+) Input |
| 10 | Voltmeter #2 Negative (-) Input |
| 11 | Voltmeter #3 Positive (+) Input |
| 12 | Voltmeter #3 Negative (-) Input |
6 Voltmeter Input Module
This module adds six voltmeter inputs to the SiteMonitor System. As the voltmeter inputs are identical to those in the 2 Shunt / 4 Voltmeter module, that section of this manual should be consulted for information on using these inputs.
The 12 position terminal block has the following pinout: Note: Pin 1 is the position closest to the 6p6c Jacks.
| Pin | Function |
|---|---|
| 1 | Voltmeter #1 Positive (+) Input |
| 2 | Voltmeter #1 Negative (-) Input |
| 3 | Voltmeter #2 Positive (+) Input |
| 4 | Voltmeter #2 Negative (-) Input |
| 5 | Voltmeter #3 Positive (+) Input |
| 6 | Voltmeter #3 Negative (-) Input |
| 7 | Voltmeter #4 Positive (+) Input |
| 8 | Voltmeter #4 Negative (-) Input |
| 9 | Voltmeter #5 Positive (+) Input |
| 10 | Voltmeter #5 Negative (-) Input |
| 11 | Voltmeter #6 Positive (+) Input |
| 12 | Voltmeter #6 Negative (-) Input |