Johnson Controls Metasys N2 Manual

Communications bus

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lntroduction

• Application Details

• Theory of Operation

• Components

• Planning Considerations

• Design Considerations

• Maximizing Your System's Efficiency

• Specifications

Installation Procedures

• Preliminary Information

• Sample Layouts

• Wiring--NCU/NEU to N2 Bus

• Wiring--ASCs to N2 Bus

• Installing the Repeater

• Installing the Fiber Modems

• Setting Terminations

• Installing the Surge Protector

• Setting the Channel Switch (NCM 101/102 Only)

Commissioning Procedures

• Overview

• Checking N2 Bus Installation

• Modifying N2 Bus Installation

Code No. LIT-636018

N2 Communications Bus

*Indicates those sections where changes have occurred since the last printing.

Metasys Network Technical Manual 636

Network Communications Section

Technical Bulletin

Issue Date 1199

www.johnsoncontrols.com

Page

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*27

*36

*48

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Summary of Contents for Johnson Controls Metasys N2

Page 1 • Setting the Channel Switch (NCM 101/102 Only) Commissioning Procedures • Overview • Checking N2 Bus Installation • Modifying N2 Bus Installation *Indicates those sections where changes have occurred since the last printing. © 1999 Johnson Controls, Inc. Code No. LIT-636018 www.johnsoncontrols.com...
Page 2 • Checking the Surge Protector • Checking the Communication Terminal Board • Checking Communication Faults Ordering Instructions • Johnson Controls Code Numbers • Vendor Code Numbers • Repair Parts * Indicates those sections where changes have occurred since the last printing.
Page 3: Application Details
Introduction The N2 Communications Bus is a local network that links controllers and Application point interfaces to the Network Control Module (NCM). The N2 Bus uses Details a manager/subordinate protocol, in which the manager device, the NCM, initiates all communication with the N2 Bus devices. These N2 Bus devices include the Digital Control Modules (DCMs), Point Multiplex Modules (XBN, XRE, XRL, XRM), and all Application Specific Controllers (ASCs).
Page 4 The N2 is based on Opto-22 Optomux protocol, which was designed for industrial applications, and is a proven communication network. The N2 Bus follows the electrical characteristics of Electronics Industry Alliance (EIA) Standard RS-485. It is optically isolated between itself and other devices (except UNT100/101, VAV100/101, and Companion...
Page 5: Theory Of Operation
N2 Bus N2 Bus DCM XM XM DCM DCM XM Base Base Base Frame Frame Frame 5-slot NCU 2-slot NEU 1-slot NEU (ILC Shown) External Wiring Internal Wiring INOUTCON Figure 2: Internal and External N2 Bus Connections The N2 Bus has three different types of communication, four priority Theory of levels, and a specific method of data transmission.
Page 6: Priority Levels
Priority Levels There are four priority levels assigned to N2 devices: 0, 1, 2, and 3, where 0 is the highest. The priorities establish how often a device is to be polled. For example, a Priority 2 device will be polled more often than a Priority 3 device.
Page 7 To take this example one step further, suppose a point object at an N2 device changes state and needs to notify you at the OWS. As mentioned before, the NCM continually polls all N2 devices over the N2 Bus for changes in status.
Page 8 The components of the N2 Bus are the N2 Bus Submodule (NCM101/102 Components only), communication terminal board, repeater, enclosure, fiber optic modem (optional), cable, and surge protector. N2 Submodule (NU-N2B101-0)--The N2 Submodule is a small plug-in unit for the NCM101 and NCM102. (The NCM401 can also use this submodule if for some reason it is no longer used as a migration NCM.) It is an interface device that the NCM101/102 requires to communicate over the N2 Bus.
Page 9 Fiber Optic Modems (S.I. Tech 2110)--These are communication devices that provide conversion between standard N2 signals (RS-485) S.I. TECH MINI OPTICAL BIT-DRIVER MODEL 2110 and fiber optic signals. Note that one pair of modems is needed for each conversion between the standard N2 cable and fiber cable. Note: We recommend that you use only the S.I.
Page 10: Planning Considerations
This section describes briefly what you need to know when planning to Planning install the N2 Bus. Considerations Space The N2 Bus requires no additional space than is provided within the NCU and NEU enclosures. The N2 Bus repeater should be installed in an inconspicuous location accessible to building maintenance personnel.
Page 11: Design Considerations
This section describes briefly what you need to know when designing an Design N2 Bus installation. A properly installed N2 Bus consists of an electrically Considerations continuous line of cable (unbroken) from one end of the system to the other. Selecting the For most N2 Bus installations, the most practical choice is solid, Right Cable...
Page 12 • The maximum distance from an NCM to the farthest device, even through repeaters, is 4572 m (15,000 ft). • You may use 18 through 26 AWG twisted pair wire; however, Johnson Controls recommends 22 AWG or heavier, because lighter wire breaks easily when stripped and installed. Network Communications—N2 Communications Bus...
Page 13: System Expansion
• The maximum distance between two fiber modems is 2012 m (6600 ft). If your application requires lengths beyond 2012 m (6600 ft), contact S.I. Tech for information about their “high power” option. • You may also use optical fiber on the N2 Bus. (A pair of fiber modems is required for conversion.) Duplex optical fiber is needed, either 50 (3.0 dB/km), 62.5 (4.0 dB/km), or 100 (5.0 dB/km) micrometers.
Page 14 • Move the LCPs and DX9100s to a separate N2 Bus, as described in the Dual N2 Bus Application Note (LIT-6363145) in the Metasys Network Technical Manual (FAN 636). If problems occur with throughput once the system is operational, monitor Monitor Your System’s the N2 network traffic using N2/L2/S2 Statistics.
Page 15: Specifications
Table 3: Specifications Specifications Category Specification Product Name N2 Communications Bus Error Checking Module 256 Checksum Address Range of 1 to 255* Devices Up to 100 (60 to 200 TC-9100s) Number of N2 Devices Baseband, 9600 baud, ASCII/Hexadecimal character Signaling Method Tested to pass IEEE 587 and 472 waveforms Surge Protection Network of voltages, biases, and resistors that are...
Page 16 Network Communications—N2 Communications Bus...
Page 17: Preliminary Information
Installation Procedures There are a few considerations that you should be aware of when installing Preliminary N2 Bus wiring throughout a building: Information • Follow all National Electrical Code (NEC) and local code restrictions. • Do not exceed the device maximums given in this document. •...
Page 18 Six sample layouts of the N2 Bus are shown in Figures 4 through 9. Also Sample shown are the proper End-of-Line (EOL) termination points. The layouts Layouts are: • standard N2 layout • N2 layout with NCU in the middle •...
Page 19 Figure 5 shows an NCU in the middle of the single N2 Bus segment. The N2 Bus in this network continues to function logically as a single bus. N1 LAN 5-slot NCU N1 and All N2 EOLs Operator Workstation Operator Workstation N2 Bus N2 Bus 1-slot NEU...
Page 20 Figure 6 shows a repeater lengthening the N2 Bus. The configuration has two segments. N1 LAN NCM's Operator Workstation Operator Workstation 5-slot NCU 1-slot NEU Repeater Side A=N2 EOL In Side B=N2 EOL In 1-slot NEU (ILC Shown) 2-slot NEU N2 Bus LAYOUT3 Figure 6: N2 Bus Layout with a Repeater...
Page 21 Figure 7 shows the N2 Bus branching from multiple repeaters. The branch can be at either Side A or B. Multiple branches off one side are also allowed, as long as the device and distance limitations are followed. This network shows three segments. N1 LAN 5-slot NCU N1 EOL...
Page 22 Figure 8 shows the standard N2 Fiber layout. Notice two S.I. Tech 2110 modems are needed for each conversion to fiber: one to convert the standard N2 signals to optics, and the other to convert optics to the standard N2 signals. N2 Bus To Local EOL=Out...
Page 23 Figure 9 shows a branched N2 Fiber layout. Any path from the NCM to an N2 device cannot go through more than two pairs of 2110 modems (i.e., cascaded modems). This is because the 2110 modems delay the N2 Bus signal, and the N2 can only compensate for two of these delays; therefore, up to two pairs of 2110 modems can be cascaded in series.
Page 24 The N2 Bus is wired to the communication terminal board of the NCU or Wiring-- NEU using the terminal block labeled TB1. Wire the N2 Bus as shown in NCU/NEU to Figure 10 (TBC801) or Figure 11 (TBC821). Be sure to follow these rules: N2 Bus •...
Page 25 Two Twisted Pair Telephone Cable Twisted IN (-) IN (+) OUT (+) REF-IN Twisted REF-IN REF-OUT REF-OUT 3-wire Twisted Cable Twisted IN (-) OUT (-) IN (+) OUT (+) Note: Coax connectors are not on BSF121. REF-IN Twisted REF-OUT N1 LAN Coax Connectors Notes: We recommend stranded 22 AWG or heavier wire.
Page 26 TBC821 Notes: Two Twisted Pair Telephone Cable We recommend 22 AWG or heavier wire. Experience has shown that 24/26 AWG wire is prone to breakage during installation. UNUSED REF-IN If shielded wire is used, wire shield to SFT GRD Twisted (soft ground) terminal for devices other than the NCM.
Page 27: Installing The Repeater
The N2 Bus is wired to the dedicated terminal block on each ASC. For Wiring--ASCs details, refer to the technical bulletin for the particular ASC. to N2 Bus You can use the N2 Bus repeater in three different configurations: station, Installing the branch, or star.
Page 28 Figure 13 shows the branch configuration, with multiple repeaters wired together and a separate branch of N2 devices off each repeater. NCM's EOL In 762 m 152 m (2500 ft) (500 ft) 305 m 305 m (1000 ft) (1000 ft) A: EOL Out A: EOL Out A: EOL In...
Page 29 Figure 14 shows the star configuration, in which the first three repeaters are installed in a central location and each device is wired from each repeater. Central Location Note: NCM's Maximum cable distance between EOL In two repeaters is 1524 m ( 5000 ft). There is no rule for minimum distance between repeaters.
Page 30 The instructions for installing the repeater include setting the baud rate, wiring the N2 Bus, and wiring the power. Refer to Figure 15. Follow these steps: Set the baud rate to 9600 baud by placing Switch 6 in the On position. Place all other switches in the Off position.
Page 31 The 2110 fiber modems can be installed in any location on the N2 Bus. Installing the Just as only two repeaters can be cascaded on the N2 Bus, only two pairs Fiber Modems of 2110 modems can be cascaded. The first installation step is to route the optical fiber and connect each modem to the ends of the fiber.
Page 32 Fiber Modem If you need to place the 2110 modem between two segments of N2 Bus, Between wire a stub length of six inches or less as shown in Figure 17 and Two Segments terminate the two pairs of N2 Bus cable at the end of the stub length. N2 + N2 - Use wire nuts to...
Page 33 In order to properly terminate the N2 Bus, you need to know the two types Setting of terminating devices. They are: Terminations • Switch-Terminating--device has an EOL switch or jumper; includes the NCM, DCM, XBN, XRE, XRL, XRM, ILC, IFC, D600, and repeater.
Page 34 • To set the EOL jumpers on the repeater, refer to Table 4 and Figure 15. Remove the cover of the repeater to get at the EOL jumpers. Note: Sides A and B have separate EOL settings. Determine the settings individually.
Page 35 Optional Shield Fold back and tape. 9-pin Connector N2 - N2 + Solder jumper wires between Pins 3-7 and Pins 8-9. eol-in Figure 19: Modem’s Cable Connector: EOL Set to In Modem Set EOL=Out To set the modem with the end-of-line selection set to Out, wire the 9-pin connector using solder connections as in Figure 20: Optional Shield...
Page 36 Surge protection is strongly recommended if the N2 Bus is wired between Installing the buildings. The protection is provided by a voltage surge Surge suppressor/protector, which is installed on the N2 Bus near the N2 device. Protector Example applications are shown on Figures 21 and 22. Figure 22 shows extra protection with the installation of one suppressor near the first N2 device and another at the point where the N2 Bus enters the building.
Page 37 Surge Protector N2 Bus Surge Surge Protector Protector N2 Bus N2 Bus N2 Bus protect2 Figure 22: Extra Surge Protector Installation The recommended surge protector is the Transient Eliminator, model TE/JC04C12, manufactured by Advanced Protection Technologies (APT). The device protects the N2 Bus from indirect lightning. It shunts both common and normal mode voltage surges to ground repeatedly without damage to N2 Bus components.
Page 38 Table 6 lists the specifications of the surge protector. Table 6: Surge Protector Specifications Category Specification Product Name Transient Eliminator Generic Name Surge Protector Model Number TE/JC04C12 Design Three stage solid-state design using both metal oxide varistors and silicon avalanche diodes for suppression Less than one nanosecond Response Time 10 kA per conductor...
Page 39 The surge protector consists of two sections: the terminal block and the main assembly. These sections separate to make the unit easier to install and replace. Refer to Figure 23. Surge Protector Unprotected Side Protected Side HRD GND HRD GND SFT GND SFT GND N2 REF...
Page 40 Connect the protector to earth ground with 12 AWG stranded green wire as shown in Figures 24 through 30. The total length of ground wire cannot exceed 4.57 m (15 ft) which means an earth ground must be available within 4.57 m (15 ft) of the N2 device. (Your installation design will have to accommodate this requirement.) For NCUs/NEUs, you may use the hard ground termination on the Communications Terminal Board (TBC), as long as the ground wire is 4.57 m (15 ft) or...
Page 41 NCU/NEU - Unshielded N2 Bus Building One Building Two Metal Enclosure Metal Enclosure Unprotected Protected Protected Unprotected N2 Bus N2 Bus N2 Bus Surge Surge Protector Protector N2 REF SFT GRD SFT GRD HRD GRD HRD GRD Notes: For surge protector's hard ground, use 12 AWG stranded wire, 4.57 m (15 ft) maximum length. Make sure wires entering surge protector's enclosure are not close to wires leaving enclosure.
Page 42 AHU/LCP/UNT/VAV - Unshielded N2 Bus Building One Building Two Metal Enclosure Metal Enclosure N2 Bus HRD GRD Metal Enclosure Metal Enclosure Protected Unprotected Unprotected Protected N2 Bus N2 Bus N2 Bus Surge Surge Protector Protector Notes: For the surge protector's hard ground (HG), use 12 AWG stranded wire, 4.57 m (15 ft) maximum length. Make sure wires entering surge protector's enclosure are not close to wires leaving the enclosure.
Page 43 AHU/LCP/UNT/VAV - Shielded N2 Bus Building One Building Two Metal Enclosure Metal Enclosure N2 Bus HRD GRD Metal Enclosure Metal Enclosure Protected Unprotected Unprotected Protected N2 Bus N2 Bus N2 Bus Surge Surge Protector Protector SURGE3 Notes: For surge protector's hard ground (HG), use 12 AWG stranded wire, 4.57 m (15 ft) maximum length. Soft ground (SG) the N2 Bus shield within one inch of entering the enclosure with a 560-1000 pF capacitor.
Page 44 IAC/IFC/ILC - Unshielded N2 Bus Building One NCM** IAC, IFC, or ILC* N2 Bus HRD GRD Building Two ** Standard, Fire, or Security NCM. Metal Enclosure Metal Enclosure Protected Unprotected Protected Unprotected IAC, IFC, or ILC* N2 Bus N2 Bus N2 Bus Surge Surge...
Page 45 IAC/IFC/ILC - Shielded N2 Bus Building One NCM** IAC, IFC, or ILC* N2 Bus HRD GRD Building Two Metal Enclosure Metal Enclosure Protected Unprotected Unprotected Protected IAC, IFC, or ILC* N2 Bus N2 Bus N2 Bus Surge Surge Protector Protector IAC, IFC, or ILC* Notes: For the surge protector's hard ground (HG), use 12 AWG stranded wire, 4.57 m (15 ft) maximum length.
Page 46 N2 Repeater - Unshielded N2 Bus Building One Metal Enclosure N2 Bus Building Two HRD GRD Metal Enclosure Protected Unprotected Unprotected Protected Side A N2 Bus N2 Bus N2 Bus Surge Surge Protector Protector Side B Side B Repeater Notes: For surge protector's hard ground (HG), use 12 AWG stranded wire, 4.57 m (15 ft) maximum length. SURGE6 Make sure wires entering surge protector's enclosure are not close to wires leaving the enclosure.
Page 47 N2 Repeater - Shielded N2 Bus Building One Metal Enclosure N2 Bus Building Two HRD GRD N2 Bus Metal Enclosure Protected Unprotected Unprotected Protected Side A N2 Bus N2 Bus N2 Bus Surge Surge Protector Protector Side B Repeater Notes: For surge protector's hard ground (HG), use 12 AWG stranded wire, 4.57 m (15 ft) maximum length. SURGE7 Soft ground (SG) the N2 Bus shield within one inch of entering the enclosure with a 560-1000 pF capacitor.
Page 48 The Channel Select switch is located on the front of the N2 Submodule Setting the (Figure 31). It configures the NCM to use one of two channels for the Channel Switch N2 Bus, Channel A or Channel B. The switch corresponds to the terminal (NCM 101/102 block on the communication terminal board to which N2 Bus wiring is Only)
Page 49: Commissioning Procedures
Commissioning Procedures Commissioning the N2 Bus includes checking and modifying the wiring Overview between all N2 devices. Troubleshooting involves performing one or more steps to isolate and correct a communication problem. Checking the N2 Bus installation involves verifying the: Checking N2 Bus Installation •...
Page 50 To add a DCM or XM to a new NEU, connect the N2 Bus to the new NEU via the respective communication terminal board. Install the device into a proper, available slot in the NEU. If this device is not the end-of-line device, set the EOL switch to Out.
Page 51: Troubleshooting Procedures
Troubleshooting Procedures The N2 Bus is a reliable communications bus. However, there are Overview situations in which communication problems may occur. Under most circumstances, you can detect a problem by examining the XMIT and RECV LEDs on the N2 device. If they are not flickering, or are flickering irregularly, the bus is not working properly.
Page 52 To verify proper cable termination, examine all N2 Bus wiring. There Checking for must not be any breaks in the three signal lines, and the wires must be Proper connected to their proper terminals. Lightly tug on each wire to ensure that Termination it is secure.
Page 53 The N2 Bus may not communicate because the length of the bus is too Checking the long. The recommendation is 1524 m (5000 ft) for each segment and a Length of maximum distance of 4572 m (15,000 ft) from the farthest N2 device. N2 Bus The N2 Bus is strictly a daisy-chained bus in which multiple devices are Checking for...
Page 54 Communication may fail if one or more of the fuses on the communication Checking the terminal board blows. The TBC801 has six fuses that protect the Communication components of the NCU/NEU from high voltages and power surges. Terminal Board (Note that the TBC821, the improved version of the TBC801, uses thermistors instead of fuses, which provide overload protection and are also resettable, so that the TBC will work again after it cools off.) The Fuses F1, F2, and F3 protect TB1;...
Page 55 TBC801 Base Frame Leads from Continuity Tester or Ohmmeter tbcfuse Figure 32: Checking Fuses on the Communication Terminal Board You can use an oscilloscope to pinpoint communication faults over the Checking N2 Bus. The procedure requires a 2-channel scope with an A minus B Communication function or an A plus B with B inverted function.
Page 56 3 to 10 V pp 0 V - (including +0.5 VDC Bias) Ch 1 = 2 V/div. scopesg T/div 0.5 mS Figure 33: N2Bus Signal as Measured with Oscilloscope 6. Connect Channel B to the N2- wire and connect Channel A to the N2+ wire.
Page 57: Ordering Instructions
Ordering Instructions Johnson Table 8: Johnson Controls Code Numbers Controls Code Description Product Code Number Numbers NU-N2B101-0 N2 Submodule BZ-1000-7 or AS-ENC100-0 Enclosure for N2 Repeater Vendor Code Table 9: Vendor Code Numbers Numbers Description Model Number Manufacturer 4683-TTM-1 (115 VAC)
Page 58: Repair Parts
If the communication terminal board or N2 Submodule is defective, Repair Parts replace it. Refer to the Warranty section of the Standard Terms page in your current Cost Schedule for information on returning defective material. If the surge protector is defective, contact the manufacturer for warranty and replacement details.
Page 59 Notes Network Communications—N2 Communications Bus...
Page 60 Notes www.johnsoncontrols.com Controls Group FAN 636 507 E. Michigan Street Metasys Network Technical Manual P.O. Box 423 Release 10.0 Milwaukee, WI 53201 Printed in U.S.A. Network Communications—N2 Communications Bus...