(Click here to go to image)

Shown above is a Sitemaster Model SMC8A16Dg10R
(Transparent door shown open)

Industry: A Multi-Site Interstate Tank Farm Operation


Each site consists of 5 to 8 large 100,000 to 500,000 gallon tanks and there are a total of 14 such sites located at remote railroad sidings scattered over 14 mid-western and western states. The product in each tank must have air bubbled thru it for one hour out of every 48 hours. This arrangement requires an attendant to visit the site, check the level of the tanks and manually start the compressor (at those sites without an electric motor driven compressor) and open then close the valve for each tank. The object is to automate the aeration at each of the 14 sites with the Sitemaster (confirming that it is actually accomplished on the automatic schedule by telephone with printout to the Site Commander) and be able to monitor the site for any problems, as well as determine the tank levels from the central office LAN in Illinois and from any laptop computer by personnel on the road.


Provide a Sitemaster Model SMC8A16Dg10R unit (with all accessory valves, level controls, connection diagrams etc. to make a complete system) for each remote site and equip the central office LAN (which has a DSL connection to the internet) in Illinois with the internet enabled Sitecommander Software. The software runs on a dedicated computer on their LAN and has a dedicated dial-in phone line used by the remote site phones (it is separate from their phone system, will not rollover, will not be picked up by an answering machine etc.-and is $12/mo. dial-in, not an expensive leased line or DSL-T1 connection which could, of course, also be used for continuous real-time control and data available on site). This computer hosts the Sitecommander Software and access to it is protected by their firewall making it virtually impossible to hack--the general public cannot gain access to the LAN (as opposed to an internet website which is open to all comers on the web), and if a hacker did, he would need a copy of the Sitemaster software pre-installed on his computer to see anything. We will refer to this computer as the Host from now on. Anyone in the central office on the LAN has level 1 access to the host (and other levels, if authorized). Any personnel on the road with a laptop (that has the Sitemaster software pre-loaded) can go to his internet service provider and our software will send an IP address which will allow pre-authorized passage (using a combination of three of the 64000 ports--very difficult for a hacker to discover, and if ever breached, then without the software it becomes almost impossible to see anything at all) thru the firewall and access to the host.

The Sitecommander Software (which can handle up to 200 sites) can be programmed to dial out and poll each site as often per day as needed. In this case, it was decided to poll and update the tank levels (for inventory indication) at 8am, 12noon and 6pm and post complete status of each site to the level one database for all to see. Those with level 2 access could go directly to the site and view the real time status of any site.

Each Sitemaster SMC8A16Dg10R monitors up to 16 (more with add on cards- see below) normally open/normally closed alarm contacts such as a thermostat, pressure sensor, magnetic door contacts, valve position proximity switches etc., and has 10 form A relay contacts that can be programmed to act in conjunction with any monitored device--thus if A happens then a relay turns B on and C off (or if A and D happen, then turn B and C on) etc. It also has the ability to accept up to 8 analog signals (4-20ma, 1-5V) which in this case are connected to the ultrasonic level sensors in up to 7 of the tanks with the eighth used to indicate outside air temperature at the site (of course, the analog signals could be used for pressure, voltage, amperage etc. sensors). In this case, the Sitemaster was set up to monitor the levels of 1 to 7 tanks at each site with readouts in feet, auto-calculated gallons and tons with each site being polled at 8am, 12noon and 6pm with details stored in the database which is available to everyone on the main office LAN. In the event of an alarm on any monitored point, a fax detailing the "nameplate" of that problem (such as no air in a particular tank at a time when it is scheduled to be there) is sent to the main office (if night time alarms must be handled, a pager could also be called-alerting the recipient to get on his laptop and see what it is).

There are three levels of access controlled by user name, password and authorized level:
Level One Access - Available to anyone on the LAN with a copy of the software pre-installed on his/her computer. This level can look at Site Status only which includes any data posted at the last update time(8-12-6pm) and any alarms posted since. No changes allowed.
Level Two Access - Can click on any remote site as shown on the Site Status page and dialout to the remote Sitemaster 16RM8A10C unit for real time status only. This assumes, of course that someone else is not on the outgoing to site/incoming line from site line assigned to the Host. No changes allowed.
Level Three Access - For access to the control section. Entry to this section is recorded by time, date and access code. This allows changes to the site settings, functions as well as real time control.

The Sitecommander software and its host can handle up to 200 separate sites per system and each Sitemaster comes with the possibility of add on boards for a total of up to 224 digital inputs/outputs (for example 124 inputs and 100 outputs etc.) and up to 72 analog inputs per site. Our standard NX--B Annunciator/Monitors can also be integrated into each site if a local audio-visual alarm is needed for those times when an attendant is present.

The ultrasonic level control transducers furnished by Visicomm, as part of our system responsibility for this particular application, are weather proof, unaffected by condensation, totally sealed and suitable for use with any liquid (not solids because of lack of a level surface to sense). Certified Class 1, Div.1 explosion proof sensors are available. Our system allows for a maximum of 72 tanks per site at each of up to 200 sites located anywhere there is a 120VAC outlet and a phone line available (including a cell phone line if need be).

As part of our system design responsibility, we also furnished a diesel engine startup and monitoring system (for some sites) and an electrically actuated stainless steel ball valve with pressure sensor (in line after each ball valve to confirm pressure) for each tank. The photo above shows a battery charger/power supply (bottom of relay rack) with battery (which provides 4 hours of operation in the event of a power outage), above which there are 5 manual bypass switches with led's to allow manual operation when personnel are present. Just below these switches there is a port for connection of a laptop. When on site, personnel can manually bypass the computer control and operate the site or they can use a laptop on site to take control. The top of the relay rack is occupied by the level control system LCD display and controls.

At another customers request, we are looking into the possibility of being able to switch on a scanning camcorder at each remote site for a look around and transmitting the sight and sound over the dial-up connection before sending someone to the site to investigate a problem--not yet available as of 7/02.

Electrocon Div. Worldwide Frequencies & Voltages Visicon Div
Frequency Converters
Motor Generators
Solid State
Visicomm Industries
911 A Milwaukee Ave.
Burlington, WI 53105
Phone: 262-767-9032
Fax: 262-767-9060
Toll Free: 1-866-221-3131
Alarm Systems
Audio Visual Alarm Panels,
Telephone Dialers