PoolPak SWHP Series ECCIII Modbus RTU BAS Interface DOCUMENT #: SVW05-ECCIIIMODBUS

Transcription

1 PoolPak SWHP Series ECCIII Modbus RTU BAS Interface DOCUMENT #: SVW05-ECCIIIMODBUS UPDATED: MAY 2018

2 INTRODUCTION PoolPaks equipped with the ECCIII controller can be directly connected to a Modbus based Building Automation System (BAS). Specifically, the protocol is Modbus RTU using an RS485 physical layer with the ECCIII acting as a slave device. The device address and baud rate can be configured in the field. 58 control points that include all basic information and set points for the PoolPak dehumidification system are available through the interface. MODBUS PROTOCOL DETAILS The protocol used by the ECCIII is Modbus RTU with 8 bit encoding and 16 bit CRC error checking. The ECCIII operates as a slave on the Modbus network. Modbus protocol implementation complies with the document: Modicon Modbus Protocol Reference Guide March 1992, PI-MBUS-300 Rev. D This document is available from the web site The communications port on the ECCIII is an optically isolated RS485 transceiver. Port settings are: 8 data bits, 2 stop bits, and no parity. The baud rate can be field adjusted from 1200 up to the factory default of by setting a configuration parameter in the ECCIII s service menu. The following Modbus functions are implemented in the ECCIII: FUNCTION CODE FUNCTION DESCRIPTION 01 Read Output Status Read digital variables 02 Read Input Status Read digital variables 03 Read Output Registers Read analog/integer variables 04 Read Input Registers Read analog / integer variables 05 Force Single Coil Write digital variable 06 Force Single Register Write analog / integer variable 15 Force Multiple Coils Write multiple digital variables 16 Preset Multiple Registers Write multiple analog / integer variables The error messages returned by the ECCIII conform to the Modbus specification. Specifically, when an error occurs, the packet sent back to the master contains the original function code with the most significant bit set to 1, followed by a byte containing the error code number. The following Modbus error codes are implemented in the ECCIII: ERROR CODE DESCRIPTION 01 Illegal Function 02 Illegal Data Address 03 Illegal Data Value If the ECCIII receives a packet with an incorrect check sum, no error message will be returned to the master. If the master requests a register value that does not exist in the ECCIII, the value will be returned as PoolPak LLC. All rights reserved. Page 2

3 ECCIII MODBUS CONFIGURATION PARAMETERS The three Modbus configuration parameters are accessed by pressing Key I on the ECCIII s Remote Terminal Unit (RTU). The password to access the service menu is After successfully entering the password, use the down arrow key to scroll down the list of parameters. The three BAS interface parameters are: 062. Baudrate This parameter sets the baud rate for the onboard serial port. It can be set to 1200, 2400, 4800, 9600, or The factory default setting is BAS Addr This parameter sets the address of the ECCIII on the Modbus network. It can be set to any integer from 1 to 247. The factory default setting is 1. Ser Port Proto This parameter sets the protocol that the ECCIII will use for the onboard serial port. For Modbus operation, it must be set to MBRTU. The factory default is RS485. A setting of RS485 causes the ECCIII to use a proprietary protocol. The MBRTU setting is also RS485, but uses the Modbus RTU protocol. PHYSICAL NETWORK CONNECTION The terminal blocks for field connection to the Modbus RTU network are located in the PoolPak s main control panel. The block is labeled T16. Terminals 1, 2, and 3 are used for connection to the network with the following functions: PoolPak recommends the use of 22 AWG shielded twisted pair cable for runs up to 500 feet. For runs greater than 500 feet, contact the factory. Use two wires from the same pair for connection of T16.1 and T16.2. Use both wires from a second pair for connection of T16.3. CONTROL POINTS MAPPING TERMINAL ID FUNCTION T16.1 Tx/Rx + (A) T16.2 Tx/Rx (B) T16.3 Ground The ECCIII s Modbus interface provides 58 control points that include all basic status information and set points for the PoolPak dehumidification system. There are three types of points available, analog, integer, and digital. Analog values are multiplied by 10 before being sent through the Modbus interface. For example, a return air temperature of 25.3 will be sent through the Modbus interface as 253. Integer and digital values are sent directly through the interface without modification. The following table lists the available points along with their address offsets and types. For more information on the use of address offsets, please refer to the Modicon standard referenced on page 1 of this document. Note: Temperatures are expressed in degrees Celsius. Temperature set points are expressed in degrees Fahrenheit. ADDRESS OFFSET DESCRIPTION POINT TYPE VAR TYPE 2 Supply Fan Current Input Register (3XXXX) Analog 3 Return Fan Current Input Register (3XXXX) Analog 4 System 1 Compressor Current Input Register (3XXXX) Analog 5 Return Air Temperature Input Register (3XXXX) Analog 6 Outside Air Temperature Input Register (3XXXX) Analog 2018 PoolPak LLC. All rights reserved. Page 3

4 ADDRESS OFFSET DESCRIPTION POINT TYPE VAR TYPE 7 Exhaust Damper Actual Position Input Register (3XXXX) Analog 8 Recirc Damper Actual Position Input Register (3XXXX) Analog 9 Outside Damper Actual Position Input Register (3XXXX) Analog 10 Air Off Evap Temperature Input Register (3XXXX) Analog 11 Cold Surface Temperature Input Register (3XXXX) Analog 12 Return Air Relative Humidity Input Register (3XXXX) Analog 13 Outside Air Relative Humidity Input Register (3XXXX) Analog 14 Air Off Evap Relative Humidity Input Register (3XXXX) Analog 15 System 2 Compressor Current Input Register (3XXXX) Analog 16 Pool 1 Water Temperature Input Register (3XXXX) Analog 17 Pool 2 Water Temperature Input Register (3XXXX) Analog 18 Supply Air Temperature Input Register (3XXXX) Analog 19 Return Air CO2 Level (ppm) Input Register (3XXXX) Analog 20 Fuzzy Logic Damper Variable Input Register (3XXXX) Analog 21 Fuzzy Logic Return Temp Var Input Register (3XXXX) Analog 22 Fuzzy Logic Return Dewpoint Var Input Register (3XXXX) Analog 23 Requested Outside Damper Pos Input Register (3XXXX) Analog 130 System 1 Active Fault Code Input Register (3XXXX) Integer 131 System 2 Active Fault Code Input Register (3XXXX) Integer 132 Compressor Stages Desired Input Register (3XXXX) Integer 133 Compressor Stages of Heat/Cool Input Register (3XXXX) Integer 134 Compressor Stages of Dehumid Input Register (3XXXX) Integer 135 Damper Position Limit Code Input Register (3XXXX) Integer 136 System 1 Fault Count Input Register (3XXXX) Integer 137 System 2 Fault Count Input Register (3XXXX) Integer 138 Return Air Temperature Set Point Input Register (3XXXX) Integer 139 Pool 1 Water Temp Set Point Input Register (3XXXX) Integer 140 Pool 2 Water Temp Set Point Input Register (3XXXX) Integer 141 Return Air RH Set Point Input Register (3XXXX) Integer 142 Damper Min Pos Limit Set Point Input Register (3XXXX) Integer 143 Damper Max Pos Limit Set Point Input Register (3XXXX) Integer 144 Return Air Temperature Set Point Holding Reg. (4XXXX) Integer 145 Pool 1 Water Temp Set Point Holding Reg. (4XXXX) Integer 146 Pool 2 Water Temp Set Point Holding Reg. (4XXXX) Integer 147 Return Air RH Set Point Holding Reg. (4XXXX) Integer 148 Damper Min Pos Limit Set Point Holding Reg. (4XXXX) Integer 2018 PoolPak LLC. All rights reserved. Page 4

5 ADDRESS OFFSET DESCRIPTION POINT TYPE VAR TYPE 149 Damper Max Pos Limit Set Point Holding Reg. (4XXXX) Integer 150 Aux Air Heat Stages Active Input Register (3XXXX) Integer 151 System 1 Operation Mode Input Register (3XXXX) Integer 152 System 2 Operation Mode Input Register (3XXXX) Integer 2 System 1 Pool Water Flow Input Status (1XXXX) Digital 3 System 2 Pool Water Flow Input Status (1XXXX) Digital 4 Occupied Mode Status Input Status (1XXXX) Digital 5 Purge Mode Status Input Status (1XXXX) Digital 6 System 1 ACC Status Input Status (1XXXX) Digital 7 System 2 ACC Status Input Status (1XXXX) Digital 8 Aux Pool Water Heater 1 Input Status (1XXXX) Digital 9 Aux Pool Water Heater 2 Input Status (1XXXX) Digital 10 Force Occupied Mode Coil Status (0XXXX) Digital 11 Force Unoccupied Mode Coil Status (0XXXX) Digital 12 Force Purge Mode Coil Status (0XXXX) Digital 13 Force No Purge Mode Coil Status (0XXXX) Digital 14 Active Alarm Present Coil Status (0XXXX) Digital CHANGING A SET POINT Two data points are allocated for each set point. One of the points is a holding register and the other is an input register. To change a set point, use function code 6 to force the appropriate holding register to the new set point value. Verify that the ECCIII has accepted the new value by reading the value back from the corresponding input register. There are value limits for each set point. If the BAS tries to set an inappropriate value, the ECCIII will apply the limits to the requested change. The BAS can detect this event by verifying the change in the input register for the set point. CONTROLLING OCCUPIED AND PURGE MODES The BAS can control the PoolPak s Occupancy and Purge Modes directly. This control overrides all internal schedules and controls in the ECCIII. To force occupied mode, use function code 5 to force the coil at offset 10 to 1 and the coil at offset 11 to 0. To force unoccupied mode, force the coil at offset 10 to 0 and the coil at offset 11 to 1. Use this same process to control purge mode with the coils at offsets 12 and 13. ACTIVE ALARM FLAG CONTROL The coil at offset 14 indicates the status of the ECCIII s alarm flag. This status corresponds to the red light inside the RTU s alarm button. When the status is 1, there is an uncleared alarm present in the ECCIII. To clear the alarm, use function code 5 to force the coil at offset 14 to 0. If there are no active alarms in the system, the coil value will stay 0. If there are still active alarms present, the ECCIII will set the coil value back to PoolPak LLC. All rights reserved. Page 5

6 SYMPTOM POSSIBLE CAUSE SOLUTION No response from ECCIII when polled by the master on the Modbus network Set point changes are different than requested by BAS. Replies from ECCIII are sporadic. Power to ECCIII is off Incorrect baud rate setting Incorrect BAS Address setting. Incorrect Serial Port Protocol setting. Serial port polarity is reversed. Requested set point value is outside of the acceptable range. Electrical interference. Turn on power to ECCIII at PoolPak control panel. Set the baud rate parameter to the correct value. Set the BAS Address parameter to the correct value. Set the Serial Port Protocol parameter to MBRTU. Swap the wires connected to T16.1 and T16.2. Select set points based on the acceptable range. Route network wiring away from other electrical devices. With more than 45 years of experience in indoor pool dehumidification equipment manufacturing, PoolPak LLC is the most well-known brand in the industry. Our people and products work daily to improve the quality and comfort of indoor pool environments. PoolPak dehumidification solutions include a variety of heating, ventilation, and air conditioning systems, in addition to an industry-leading PoolPak support network. For more information, please visit Industrial Drive York, Pennsylvania USA Fax PoolPak LLC. All rights reserved. SVW05-ECCIIIModbus