Daikin Modbus® Communication Module

Introduction

This manual describes how to install or replace a Modbus® communication module on a MicroTech® 4 Rebel Applied® unit controller. It also explains how to set network parameters and establish communication between the unit controller and Modbus network.

Reference Documents

• Company: Daikin Applied, Title: MicroTech 4 unit controller for Rebel Applied Rooftop Systems, Number: OM 1288, Source: www.DaikinApplied.com
• Company: Daikin Applied, Title: MicroTech 4 Rebel Applied Modbus Network Integration, Number: ED 19133, Source: www.DaikinApplied.com
• Company: Modbus-IDA.ORG, Title: Modbus Application Protocol Specification V1.1b, Source: www.Modbus.org
• Company: Modbus-IDA.ORG, Title: Modbus over Serial Line Specification and Implementation Guide V1.02, Source: www.Modbus.org

NOTICE: This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with this instruction manual, may cause interference to radio communications. It has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his or her own expense. Daikin disclaims any liability resulting from any interference or for the correction thereof.

Software Revision

This document supports BSP (Board Support Package) Modbus communication module firmware v11.18 and all subsequent versions until otherwise indicated.

Hazard Identification

⚠️ DANGER: Danger indicates a hazardous situation, which will result in death or serious injury if not avoided.

⚠️ WARNING: Warning indicates a potentially hazardous situations, which can result in property damage, personal injury, or death if not avoided.

⚠️ CAUTION: Caution indicates a potentially hazardous situations, which can result in minor injury or equipment damage if not avoided.

? NOTICE: Notice indicates practices not related to physical injury.

? NOTE: Indicates important details or clarifying statements for information presented.

Features

• Integration into a building automation and control system via Modbus RTU
• Simple attachment to a MicroTech unit controller
• LEDs indicate communication status and network activity
• Modbus baud rate, parity, and other network parameters set directly from the unit controller
• Circuit board components enclosed in protective housing

Specifications

The following section provides a summary of technical data and conformance to agency listings.

General

• Dimensions: W x H x D: 1.77 x 4.33 x 2.95 in (45 x 110 x 75 mm)
• Weight: 3.5 oz (85 g)
• Material: Base - plastic, pigeon-blue; Housing - plastic, light-gray

Operating

• Temperature: -40 - 158°F (-40 - 70°C)
• Humidity: <90% RH
• Atmospheric pressure: Min. 10 psi (70kPa), corresponding to max. 9,842 ft (3,000 m) above sea level

Storage and Transportation

• Temperature: -40 - 158°F (-40 - 70°C)
• Humidity: <95% RH
• Atmospheric pressure: Min. 3.77 psi (26 kPa), corresponding to max. 32,808 ft (10,000 m) above sea level

Electrical

• Power: Supplied via unit controller; DC 5 V (+5% /-5%), max. 140 mA
• Network connection: RS-485 (EIA-485) - T1 and T2; 3-wire twisted pair, shielded; Galvanically isolated
• Bus connection/Transceiver: +, -, REF (3 wires); Isolated transceiver with fail-safe circuitry; 1/8 Unit load
• Bus termination: 680 Ω / 120 Ω +1 nF / 680 Ω (switch by software)
• Baud rate: 4800, 9600, 19200, and 38400

Additional Components

• Board-to-board connector: 10-pin plug between communication module and unit controller
• Modbus network connector: RS-485 connection plug, 3-pin spring cage top entry

Agency Listings

• US: UL916, UL873
• Canada: CSA C22.2M205
• Europe: EMC directive 2004/108/EC; Low-voltage directive 2006/95/EC; RoHS directive 2002/95/EC

Dimensional Data: The module measures 1.77 inches (45 mm) wide, 4.33 inches (110 mm) high, and 2.95 inches (75 mm) deep. The top view shows the board-to-board connector and RS-485 ports. The side view details the physical dimensions and mounting points.

Component Data

The Modbus communication module is a printed circuit board with a plastic enclosure. It connects directly to the left-hand side of the MicroTech unit controller. It may attach to an existing module if one is already connected.

Light Emitting Diodes (LEDs)

The module features a BSP LED and a BUS LED to indicate communication activity and status. These are visible when the module is connected and powered.

BSP LED

The BSP LED indicates the communication state between the Modbus communication module and the MicroTech unit controller.

¹ In the event of an error, cycle power to the unit controller. Contact Daikin Applied Controls Customer Support at 866-462-7829 or Controls@daikinapplied.com for assistance.

BUS LED

The BUS LED indicates the communication status between the Modbus communication module and the Modbus network.

¹ If the Com LED Timeout parameter is set to 0, the timeout feature is disabled. See Table 3 for additional information.

² If the timeout is set to 0 and therefore disabled, the LED remains green even in the event of a communication error.

Modbus Network Connector

The connection to the Modbus is made via the T1 and T2 ports. An RS-485 connection port connects the module to the Modbus Network. It has three pins: +, -, and Ref. Only the top connector (Channel 0) is used.

Board-To-Board Connector

A 10-pin board-to-board connector connects the MicroTech unit controller to the Modbus communication module.

Installation

This section describes how to field install a new Modbus communication module or replace an existing one on the MicroTech unit controller.

⚠️ WARNING: Electric shock hazard. The terminals on the unit controller are high voltage. Disconnect power to avoid electrical shock potential, which may result in personal injury, serious injury, death, or equipment damage. This equipment must be properly grounded. Connections and service must be performed only by knowledgeable personnel.

Field Installation Kit

The field-installed kit includes:

• The Modbus communication module with RS-485 network connector
• Board-to-board connector
• This manual (IM 1374)

Installing a New Communication Module

Follow these steps to install a Modbus communication module on the unit controller. The module can connect directly to the unit controller or to an existing module. A limit of three devices can be attached to the left side of the unit controller.

1. Set the "Control Mode = Off" from the HMI Main Menu on the unit controller display. This must be done prior to installation.
2. Remove power from the unit controller.
3. Carefully remove the blue plastic knockout strip on the far left end of the unit controller (or additional module). This is done by inserting a small flathead screwdriver into the tab on the bottom of the unit controller and pulling away from the controller.
4. Carefully remove the blue plastic knockout strip on the right side of the Modbus communication module.
5. Insert the board-to-board connector into the Modbus communication module. Ensure baffles align with corresponding slots in the module and unit controller. The connector only fits one way.
6. Insert the other end of the board-to-board connector to the far-left side of the unit controller or other attached module.
7. Insert the network cable into the Modbus communication module's top network connector, Channel 0.
8. Apply power to the unit controller. The unit controller will automatically reset itself approximately 30 seconds after power is applied, synchronizing with the new module.

Replacing a Communication Module

Follow these steps to remove an existing Modbus communication module and replace it with a new one:

1. Set the "Control Mode = Off" from the HMI Main Menu on the unit controller display. This must be done prior to removal.
2. Remove power from the unit controller.
3. Locate the Modbus communication module on the left side of the unit controller.
4. Gently pull the network cable connector from the Modbus communication module.
5. Carefully pull the Modbus communication module from the unit controller (or adjacent module).
6. Install the new Modbus communication module:
   • To prevent damage, insert a small flathead screwdriver into the tab on the bottom of the unit controller and pull away from the controller to remove the knockout strip.
   • Carefully remove the blue plastic knockout strip on the right side of the Modbus communication module.
   • Insert the board-to-board connector into the Modbus communication module, ensuring baffles align with slots.
7. Insert the network cable into the Modbus communication module's top network connector, Channel 0.
8. Apply power to the unit controller. The module is now ready for network configuration.
9. Follow the next section to set Modbus addressing parameters. The unit controller will reset approximately 30 seconds after power is applied to synchronize with the module.

Network Addressing

This section describes how to configure the Modbus communication module for BAS network integration using the MicroTech unit controller.

Network Considerations

Standard Modbus network rules apply. The network is a daisy-chain. The Modbus standard recommends network termination on each end with approximately 120 ohms impedance. Refer to Modbus specifications (www.Modbus.org) for guidelines.

Modbus Configuration

Configuration is done via the unit controller HMI keypad. The Modbus network address (ident number) and transmission (baud) rate must be set.

? NOTE: Set the network address within the valid range of 1-247 and verify the baud rate before the unit controller can properly communicate. These parameters are only available when the communication module is correctly attached.

Table 3 details addressing parameters for communication between the unit controller and the BAS. Boldface items are required for minimum network configuration.

? NOTE: This procedure assumes the module is attached and the controller is powered. If the module is available but not attached, see the Installation section. For part numbers, see Service Information.

Configuring Network Address and Baud Rate

1. Remove and re-apply power to the unit controller.
2. Enter the password from the HMI Main Menu:
   • Turn the circular knob until "Enter Password" is highlighted, then press the knob.
   • Enter password 2526 and press Enter. (If not at the Main Menu, press Back until it appears.)
3. Set "Control Mode = Off" from the HMI Main Menu.
4. Proceed to Step 6 to set the network address.
5. Scroll to "BMS Communications\Modbus Set-Up" and press Enter.
6. Scroll to "Address" and press Enter. Change the parameter to the value specified by the BAS network administrator.
7. Press Enter again to confirm.
8. Proceed to Step 9 to set the baud rate.
9. Scroll to "BMS Communication\Modbus Set-Up" and press Enter.
10. Scroll to "Baud Rate" and press Enter to select the desired baud rate (e.g., 19200 bps). The default baud rate is 38400 bps.
11. Press Enter again to confirm selection.
12. If network configuration is complete, proceed to "Apply Changes and Cycle Power" (Steps 17-19). Otherwise, skip to Step 17. All changes must be made before saving.

Set Additional Network Parameters

Adjust other network parameters as needed:

1. Scroll to "BMS Communication\Modbus Set-Up" and press Enter.
2. Scroll to the desired parameter and press Enter.
3. Change the value and press Enter again to confirm.
4. Repeat steps 13-15 as needed.
5. ? NOTE: Make all changes before cycling power to the unit controller.

Apply Changes and Cycle Power

1. Scroll to "Apply Changes" and select "Yes" to save the changes.
2. Cycle power to the unit controller.
3. Navigate back to the "BMS Communication\Modbus Set-Up" menu to verify the parameter settings. This may take a minute as the module powers up.

? NOTE: Refer to the MicroTech 4 Rebel Applied Unit Controller Operation Manual, OM 1288, for additional HMI information. Refer to Network Protocol Document ED 19133 for Modbus register descriptions at www.DaikinApplied.com.

Configurable Parameters

Table 3 defines all Modbus addressing parameters supported by the communication module, accessed via the unit controller HMI Main Menu/BMS Communication/Modbus Set-Up.

¹ Parameter must be configured from the HMI keypad display.

² Boldface indicates required parameters for minimum network configuration.

? NOTE: If unit controller application software requires a field upgrade, network configuration parameters revert to defaults. Contact Daikin Applied Controls Customer Support at 866-462-7829 or Controls@daikinapplied.com for assistance.

Service Information

Troubleshooting

Follow these procedures if you are not able to communicate with the unit via the network:

General

• Review the Installation section to confirm procedures were followed correctly.
• Review the Network Addressing section to confirm procedures were followed correctly.
• If the Modbus communication module is installed but LEDs are not active when the unit controller is powered up, remove the module and follow the "Installing a new Communication Module" steps. If the issue persists, replace the module.
• Verify Modbus wiring is connected to channel 0 (top port) of the communication module.
• Verify that the Modbus Set-Up menu appears in the unit controller HMI keypad display. If not, follow this procedure:
  1. Set "Control Mode = Off" from the HMI Main Menu.
  2. Remove power from the unit controller, wait 10 seconds, then re-power. Within 45 seconds, the unit controller should recognize the module and cycle power.
  3. Verify the Modbus Set-Up menu now appears.

Network Parameters

• Verify the network address of the Modbus communication module is unique. Baud rate, stop bit, and parity settings must match other server devices.
• Ensure no duplicate devices exist and network parameters are set correctly per Table 3.
• View the Modbus communication module BUS and BSP LEDs. Refer to Table 1 and Table 2 for explanations of communication status based on LED activity.

Network Wiring

If performance is unsatisfactory or the network experiences issues like noise or slow transmission:

• Confirm the shield is landed at only one point in the trunk.
• Recommended topology is daisy-chain (no T-Taps or ring layout).
• Verify network wiring does not exceed 4000 ft total distance limit (without repeaters) at 38400 bps baud.
• Verify polarity is maintained.
• Check for end-of-line termination resistors (120 Ω) at the first and last device on the trunk, as required by EIA-485.
• Verify the network trunk avoids strong sources of electromagnetic interference (EMI).
• Note that the two-wire bus is not interchangeable and must be connected correctly.
• Verify the network trunk is not located near a DC load switch (relay).

Network Performance

• If network traffic is slow, intermittent, or experiencing "noise," a network protocol analyzer or oscilloscope may be needed to determine the source of poor performance.
• Confirm power is applied to the unit controller.

Parts

To find your local parts office, visit www.DaikinApplied.com or call 800-37PARTS (800-377-2787).

Technical Support

Contact the Daikin Applied Controls Customer Support group at 866-462-7829 or Controls@daikinapplied.com for additional assistance.

Refer to the MicroTech 4 Rebel Applied Unit Controller Operation Manual, OM 1288, for additional information on using the keypad/display to set unit parameters and defaults. Also refer to Network Protocol Document ED 19133 for descriptions of the available Modbus registers (www.daikinapplied.com).

Revision History