Best Practices and Requirements

Transcription

1 Wireless in Agriculture Best Practices and Requirements Field Radio Installations Best Practices: Field Radio Installations Requirements for AG Market Banner Engineering Steve Kaminski Business Development Manager- Wireless Products ,

2 Contents Antenna Installation... 2 Antenna Cabling... 2 Surge Suppression Requirements... 3 Enclosures... 4 Sensor Cabling... 5 Solar Panels... 5 Mounting and Elevation Poles... 6 Installation Images... 8 Radio Installations... 8 Solar Panel and Charger Installations... 9 Sensor Installations Mounting Installations Field Radio Installations Requirements 1

3 Antenna Installation 1. Use the specified antenna mounting procedures in Banner Engineering s DX80 Series manual a. Use rubber splicing tape and vinyl electrical tape over the top of all antenna and cable connections to completely seal the connections, including the connection on the bottom of the radio enclosure and especially if entry of the cable is on the top of the enclosure. b. Avoid top entry connections of cables into enclosures. i. Especially where chemicals and fertilizers are applied. ii. External connections of SMA type antennas must also follow this practice. 2. Any radio that is connected to other devices via serial communications such as a PLC, controller, etc. and has an elevated / externally mounted antenna must use the DC Blocking surge suppression as specified in the Banner Engineering DX80 Series manual (Banner Model BWA- LFNBMN-DC). This surge suppression unit MUST be properly grounded to a grounding rod with proper gauge wire. Please refer to section titled Surge Suppression below. a. The best method is to have the grounding plate/mounting bracket that is supplied with the surge suppression unit to be mounted outside the enclosure to allow for all high voltage to be shunted off external to the radio enclosure. b. Mount the surge device as close to the radio enclosure to ensure that as much of the potential static buildup on the antenna cable is negated just prior to the radio (in essence, cover as much of the exposed extension cabling as possible). 3. Only use antennas that do not allow for exceeding the maximum FCC allowances for a 1 Watt, 900 MHz radio. The antenna must also be rated for MHz and 50 Ohms. When choosing the antenna, consider the losses associated with antenna cable lengths, surge suppression devices, antenna cable connectors, etc. Review the full Banner Engineering installation manual for calculating your system s total RF performance. 4. The supporting structure or pole for the antenna must be able to handle anticipated wind loads for the area and should be properly secured. If at all practical, use the mounting hardware provided with the antenna to ensure the best mounting practice. 5. Locate an OMNI style antenna away from any metal structure that could block or reflect the signal. Examples of this would be the center leg of a pivot machine or metal sided buildings. The metal structure acts as a reflector to the RF signal. Antenna Cabling 1. Secure all antenna cables to the antenna mast at least every 24 inches with properly sized zip ties or equivalent securing methods to prevent antenna cables from movement potentially causing premature wear and failure. 2. If the antenna is mounted on a pole with an open top and bottom, route the antenna cable down through the pole with an appropriately sized relief/working loop on top and bottom of pole (be sure to protect the cable from damage due to metal edges, etc.). The relief loops are not only to create drip loops, but also to allow for excess cable that may be needed when maintenance or replacement of cable, antenna, enclosure, etc. is needed. Field Radio Installations Requirements 2

4 3. Secure all additional antenna extension cable lengths with a minimum of loops to minimize a reduction in the performance of the antenna solution. 4. For horizontal support of the antenna cable (such as in an application where the radio enclosure is on one pole mount and the antenna is on another), do not lay the cable on the ground. The cable needs to be supported via a horizontal beam running between the two poles. This beam can be made of the same material as the mounting poles or use a section of Unistrut to support and capture the cable. This also prevents future damage to the cable from lawn/area maintenance or people walking on the cable. Surge Suppression Requirements Use DC blocking surge suppression devices on all outdoor applications with elevated antennas that use Type N connectors. 1. The primary reason for on Type N connector applications is that there are no manufacturers of DC Blocking surge suppression devices that make them with SMA style connectors. This is a practical approach as an antenna that uses an SMA connector should not be the primary approach used for an elevated external antenna. The db loses through the typical SMA cable (small diameter LMR/RG cabling) and connectors would likely nullify the effect of the elevated small dbi antenna associated with SMA connectors. 2. The DC Blocking surge suppressors begin to discharge voltage at 200 millivolts. Standard gas discharge tube devices begin discharging at 600 volts. The driver of this can be static (accumulated/accumulating on the plastic jacket of the antenna cable) that will adversely affect the performance of the radio system. The typical symptoms associated with a static build-up include the following: a. Degraded RF performance - Initial radio site survey is very strong or stable above 80% Green (G), but after a short period of time (1-4 weeks) the site survey would be greatly diminished (more than 30% Missed (M)) if there is a connection remaining to the field radios. b. Degraded or no communications between Gateway radio and additional control devices such as VFDs or PLCs. Communications such as Modbus 485 or standard 232 serial protocols would be affected. i. The static build-up can create issues on the physical communications connection (via wires) between the units. ii. This will also affect Ethernet IP communications as well. c. Degraded operation of the system because of electrical noise transferring between devices via electrical connections. i. Interposing relays will greatly diminish this situation versus direct connection between the influenced device (radio with the remote antenna) and the device it is directly wired to. For example, one of the radio s outputs directly wired to an input on a VFD (such as the enable input, etc.). ii. An interposing relay can provide isolation between the devices. 3. Properly ground the surge suppression device. Without a ground path, the energy will continue to accumulate and result in the same faulty operations. Field Radio Installations Requirements 3

5 4. Properly seal the surge device and all associated connectors on the antenna cable with the materials described in Antenna Installation and Antenna Cabling. 5. Perform a site survey after finalizing installation procedures and document for future reference. 6. Refer to Best Practices Performing a Signal Site Survey document for recommended antenna system modifications based on operation feedback. 7. For applications where a DC Blocking surge suppressor is not available (such as a radio system using a SMA style antenna with an antenna extension cable), secure the antenna cable (with electrical tape or zip ties for example) to a ground metal pole or structure to assist in shunting potential static electricity. This should be done to provide multiple points of contect with the grounded equipment to provide maximum opportunity to shunt. Enclosures 1. Install liquid tight pressure equalizing enclosure venting methods on all outdoor/exposed radio housings or enclosures. Without the vent, there is a high probability of condensation developing in the radio housing or an external enclosure because of the extreme temperature swings and water applications where crops are grown. a. Ex. Heyco 3546VB i. ct.cfm?product=liquid-tight-threaded-vent- Plugs&section=Venting_Pressure_Equalization_Drain_Solutions ii. The vent is included with many models (including H1, H12, and H14) of Banner Engineering radios including the appropriate Teflon tape. The vents can be mounted via the top ½-in NPT threaded fitting on the radio when mounted vertically. If the threads are properly wrapped with the Teflon tape and the vent is fully seated, the vent provides a proper seal with the built-in gasket. 2. Mount all radio enclosures at an appropriate height to allow for convenient maintenance and troubleshooting. Do not mount enclosures at the top of antenna or solar panel elevation poles. This is a safety aspect for the installer and the end customer. 3. Use a simple enclosure wire clasp as an inexpensive method to ensure the enclosure has not been tampered with or entered. 4. Radio enclosures must be securely mounted to take the weight load of the components and the wind load they may experience through year-round exposure. 5. Install the radio or enclosure facing north to provide as much protection from the sun as possible. 6. If an enclosure is not used, install a basic sun visor/shield to protect the radio from sunlight or excess water from an overhead irrigation system. A formed Plexiglasss cover with a hole drilled through it to support the antenna in a vertical position is a best practice for exposed radios. 7. If it is necessary to install additional light-weight products inside the radio enclosure, Gorilla Glue s Two-Sided Tape is exceptionally good. It (or other Field Radio Installations Requirements 4

6 equivalent tape) can typically be purchased at The Home Depot, Lowes, or other home improvement locations. Sensor Cabling 1. On radio housings exposed to outdoor weather, install cable glands, pressure equalization vents, and plugs according to the Banner Engineering requirement for proper sealing with the supplied Teflon sealing tape. All glands, vents, and plugs must be fully inserted and tight to provide water tight seals. 2. Secure all extra cabling (sensors) in an appropriate and clean method (typically electrical zip ties are very effective). Do not allow bundled cables to be exposed to the weather conditions as there is a physical damage potential. We advise tucking extra cables into the protective cavity of a pole section, such as UNISTRUT. 3. Protect sensor cables that extend down below 4 ft with either rigid PVC piping or flexible electrical conduit to protect against rodent/insect destruction. Install the cable protection to not allow water to fill the conduit and freeze. This can be done with electrical sealing tape, putty, or a liquid electrical tape such as from Permatex. Reasons for doing this include avoiding animal destruction or damage from trimming and maintenance processes. 4. All cables (sensor and antenna) coming into the enclosure are to have an appropriate drip/strain relief loop on them to prevent water entry into the radio enclosure. Use and seal properly sized cable grips. Banner Engineering offers several cable gland products with multiple access holes to allow proper sealing around all cables entering the enclosure. 5. Because of the chemicals that could potentially be used, we advise properly wrapping all quick disconnect fittings (molded on or field wired) with rubber splicing tape and cover with vinyl electrical tape. 6. Any external quick disconnect fittings should be filled with non-conductive dielectric grease such as Permatex that can be purchased at any automotive supply store or general merchandizers such as Wal-Mart. Dielectric grease must be a non-conductive, silicone-based grease that's designed to seal out moisture and prevent corrosion on electrical connectors. Solar Panels 1. When mounting a solar panel, it must be completely clear of present growth as well as anticipated growth through next scheduled maintenance/service cycle. 2. Mount the solar panel using a mounting bracket that is properly secured in at least two points and is substantial enough to take anticipated wind loads. 3. Mount the solar panel at the proper angle for the location and to provide proper protection to the unrated wiring box on the underside of the panel. Use a zip tie securing pad on the underside of the solar panel or on the frame of the solar panel to provide proper strain relief on the cable from the solar panel to the radio enclosure. 4. Mount the panel with the collecting surface facing south and at the proper angle for the latitude. Field Radio Installations Requirements 5

7 5. Secure all wiring connections to the solar panel from the radio/battery enclosure (a zip tie every 24 in). Use the proper stress relief loops and sealing to avoid creating power issues caused by damaged, stretched, or disconnected cables. Mounting and Elevation Poles 1. Using a commercially available galvanized metal mounting system such as UNISTRUT or other U channel product is recommended. A 1½ x 1½ square pole is required for installations of 8 ft or higher above grade. For shorter elevations, such as 6 ft or less, a 1½ x ¾ (image at right) rectangular pole is acceptable. Be sure to use the 10-gauge version for maximum support. A U channel style pole is beneficial as it provides the following: a. It is commercially available through home improvement stores, commercial electrical supply houses, etc. b. By having an open side, it is very easy to route sensor, antenna and other cables in the protective trough. This allows for items such as solar panels, battery/charger enclosures, or radio enclosures to be assembled in a shop setting and simply slide onto the pole and cables routed in the field. c. The slots on the back allow for quick and easy cable pass through at connection points such as solar panels or radios. d. You can use standard accessories for mounting the radios such as ¼-in Nylon Cone Nut (Image to right). e. Strut U-Bolt Beam Clamp U-Bolt clamping method is the simplest method for mounting all other components to the U channel pole. The spacing of the threaded areas matches with many antenna mounting brackets and the solar panel mounting brackets offered by Banner Engineering. f. Installation in the field only requires a post pounder and ladder, no need to dig a hole for elevation sections of 10 ft or less. g. 20 ft lengths of U channel or similar products are commercially available. 2. Insert to a proper depth relative to the amount of pole/structure exposed above ground to allow for equipment weight and wind load. 3. Use a primary mounting tube if the mounting pole must either be removed for trimming/harvesting/etc. operations or simply laid down out of the way during these processes. a. A simplified method is to use a 2-in I.D. square tube inserted in the ground to a proper depth (to support the height of the support pole). This would typically be 24 inches. b. Drive the pole in relative to the flat sides of the square tube being aligned to North/South/East /West. This ensures proper orientation of the solar panel (if so equipped) and the radio/enclosure. c. Use a through hole and bolt on the primary tube in the ground for either future removal of the tube or to secure the elevation pole to the primary pipe in the ground. Field Radio Installations Requirements 6

8 4. By properly direct mounting in the ground, a secure grounding method will be achieved. If you use a primary insertion tube in the ground to allow for easy maintenance and troubleshooting, you must provide a proper grounding connection. a. Secure the elevated removable pole section from rotating in the insertion tube. A single thru bolt/nut will suffice for this purpose. b. If a telescoping solution is required, UniStrut (for example) offers a product known as TeleStrut which allows for multiple sections to slide inside a slotted square tube. 5. Attaching the radio to the support post can be done cost effectively by using plastic or vinyl trim boards that are also readily available at home improvement stores. Because it is designed for outdoor applications it is very stable, will not promote mold/mildew, and will not require any maintenance while delivering a superior looking solution. a. The material can be drilled and cut easily in the field for on-site alterations. b. Using the ¼-in UniStrut nuts allow for simple mounting of the board to the U Channel product. c. The radios can be easily mounted to the board with #12 x3/4 stainless steel screws to ensure a secure mount that will not corrode. Field Radio Installations Requirements 7

9 Installation Images Radio Installations (note the vent is mounted via the top ½ NPT through hole in all pictured installs) Field Radio Installations Requirements 8

10 Solar Panel and Charger Installations The plastic vinyl mounting boards can also be used for supporting the radio/battery/charger enclosure. This allows for easy removal if needed for repairs, updates, etc. Field Radio Installations Requirements 9

11 Sensor Installations Use proper protective materials to protect sensor cables such as on soil moisture probe. A good option for this is LiquidTight conduit. It is non-conductive and will not corrode. Mounting Installations Securing cables (antenna or sensor) running between different mounting poles can be done by using a horizontally mounted section of UniStrut (for example). This also provides a layer of physical protection. Field Radio Installations Requirements 10