Modbus RTU

Modbus RTU Configuration

CoolMasterNet Modbus RTU is activated with below command:

>line type L3 CG5 OK, Boot Required! >

CoolMasterNet has to be restarted to run Modbus RTU for the first time. To quire current Modbus RTU configuration use line command:

>line L1: SA Master U00/G00 myid:E5 Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0 L2: DK Slave U00/G00 myid:0B Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0 L3: CG5 Modbus Address:0x40(64) 9600_8N1 Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0 L4: MH SLink:N U00/G00 myid:C900 Tx:0/2 Rx:0/2 TO:0/0 CS:0/0 Col:0/0 NAK:0/0 L5: Unused Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0 L6: Unused Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0 L7: LG Master U00/G00 Tx:983/1066 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0 L8: Unused Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0 OK >

Virtual Address (VA) Concept

In order to simplify translation of the UID (like L5.102) into Modbus object address, CoolMasterNet uses VA, associated with UID. Each UID can have none, one or a number of associated VA's. VA's are plain numbers starting from 001 (decimal). To let CoolMasterNet automatically associate VA's with existing (visible with ls command) UID's run:

>va auto OK >

This command will delete all existing associations and will create new associations one to one (one VA to one UID). At any time VA associations list can be retrieved with plain va command:

>va L1.101 --> 001 [Hex: 0x0011 | Dec: 00017] L1.102 --> 002 [Hex: 0x0021 | Dec: 00033] L1.103 --> 003 [Hex: 0x0031 | Dec: 00049] L1.104 --> 004 [Hex: 0x0041 | Dec: 00065] L1.105 --> 005 [Hex: 0x0051 | Dec: 00081] OK >

Hex and Dec numbers printed after VA are Base Address used to access Modbus objects related to UID-VA association. Base Address can be calculated as BaseAddress = VA*16 + 1. For example Indoor Unit L1.102 has associated VA = 002, thus Base Address = 2*16+1 = 33.

Discrete Inputs, Coils and Registers

Once the Base Address is determined, access to the specific Indoor Unit parameter(s) is done via Modbus objects listed below.

Base Address	Discrete Inputs	Coils	Holding Registers	Input Registers
+0	Reserved	On/Off	Operation Mode	UID
+1		Filter Sign	Fan Speed	Room Temperature x10
+2		Reserved	Set Temperature x10	Failure Code String first two characters
+3			On/Off	Failure Code String last two characters
+4			Filter	Reserved
+5			Swing
+6			Room Temperature x10 (RO)
+7			Failure Code (RO)
+8			Lock Bits
+9	Digital Input 1	Digital Output 1	Reserved
+10	Digital Input 2	Digital Output 2
+11	Digital Input 3	Digital Output 3
+12	Digital Input 4	Digital Output 4
+13	Digital Input 5	Digital Output 5		Analog Input 1
+14	Digital Input 6	Digital Output 6		Analog Input 2
+15	Reserved	Reserved		Reserved

UID Encoding

MSB Bits 15..12	Bits 11..8	LSB Bits 7..0
Ln	X	YY

Corresponds to Ln.XYY (like for example L1.102)

Operation Mode Encoding

0 - Cool	1 - Heat	2 - Auto	3 - Dry
4 - HAUX	5 - Fan	6 - HH
8 - VAM Auto	9 - VAM Bypass	10 - VAM Heat Exch.	11 - VAM Normal

Fan Speed Encoding

0 - Low	1 - Medium	2 - High
3 - Auto	4 - Top	5 - Very Low
	7 - VAM Super High	8 - VAM Low Fresh Up
9 - VAM High Fresh Up

Swing Encoding

0 - Vertical	1 - 30 deg	2 - 45 deg	3 - 60 deg
4 - Horizontal	5 - Auto	6 - OFF