Operating Parameters For The Kwl Modbus Rs485; Kwl Modbus Rtu; The Standard Structure Of The Data Package; Table Of Key Ids And Configuration Data - Helios KWL EC D Série Notice De Montage Et D'utilisation

Installation and Operation Instructions
CHAPTER 1
KWL Modbus RS 485 – Communication protocol
1 .0
Operating parameters for the KWL MODBUS RS485 (RTU) measurement data unit:
- 9600Bd - 8 Data Bits
- 1 Start Bit - 1 Parity Bit
Each unit should support even parity. If parity is not used, this will be signalled by a second Stopbit.
Notification measure:
Master – Controller / ext. programme
Pin assignment:
The double data a/b is required for the internal bus,
IMPORTANT: Only connect 1x Data a/b!
– Reprogramming the Modbus address:
Connect the KWL unit to the Modbus (address 1) and change the address on the customer-
supplied control unit. Another unit (with address 1) is then connected to the Modbus.
1 .1

KWL Modbus RTU

In RTU mode, the start of transmission is marked by a transmission pause of at least three characters. The length of the
transmission pause depends on the transmission speed. The address field consists of eight bits. The KWL unit returns
the address in its response to the controller, so that the Master can assign the response. The function field consists of
eight bits. If the KWL unit correctly receives the request from the Master, it will respond with the same function code. If
an error has occurred, it will change the function code by setting the highest bit of the function field to 1. The data field
contains instructions concerning which register the KWL unit should read out and the start address. The KWL unit uses
the read-out data in the data area in order to send it to the Master. In the event of an error, an error code will be transmit-
ted. The field for the checksum is 16 bits. The entire data package must be transmitted in one continuous data stre- am.
If there is a transmission interruption longer than 1.5 characters between two characters, then the data package should
be assessed as incomplete and discarded by the recipient.
1 .2 The standard structure of the data package [hex]
START
> 3.5 char.
Data block length:
Size of ADU on RS-485 = 253 bytes PDU + address (1 byte) + CRC (2 bytes) = 256 bytes
Address:
The Master has no specific address. Only the KWL unit must have an address which is exclusively relevant for the KWL
Modbus RS485 network.
CRC checksum:
A field with a generating polynomial x
1 .3 Table of key IDs and configuration data from the unit
Code MB Address
6/16/3 10000
10001
10002
10003 Temperature bypass control
10004
10005
10006
10008
10009
At 1:100 % outgoing air and
10010 Temperature sensor selection
10011
10012
10018
10050
- 1 Stopbit
Slave – KWL unit control electronics
Modbus message
Address Function
8 bits 8 bits
16 + x 15 + x 1 + 1.
Meaning
Unit type "KWL EC..."
Air quality sensor
Volume/pressure constant
Preheater off / on
External auxiliary heater
Calibration
Air quality level
Fire alarm contact
Volume flow on / off
0 % outside air
Operating mode
Volume flow adjustment
Required pressure
Altitude difference
1
Data CRC
N * 8 bits 16 bits
Range Unit
N<2;4>
W<5;7>
N<7;9>
W<10;12>
0-None [-]
1-CO
2
2-RH
3-VOC
<0;1> [-]
<0;20> [°C]
<0;1> [-]
0 – none [-]
3
<0;2600> [m /h]
<1;100> [%]
<0;1> [-]
0-T-outs. air [-]
1-T-extract air [-]
[-]
2-T-extract air
0-manual [-]
1-auto [-]
<-50;+50> [%]
<1;1000> [Pa]
<0;5000> [m]
EN
1 - data B
2 - data A
3 - GND
4 - +
5 - data A
6 - data B
END
> 3.5 char.
Factory setting
2
0
0
15
1
0
700...2600
50
0
0
0
0.0
20
400