VIII.5. MODBUS and BACNET table
VIII.5.a. MODBUS information
Introduction
Corrigo E ventilation is a pre-programmed application for control of an air handling unit (CTA). The Corrigo E controller
can either be used as a stand-alone unit or integrated in an existing EXO project. In both cases it is configured via the
display or using the configuration tool E tool on a PC. This document describes all the signals that can be accessed via
EXOline or Modbus. This document does not describe how to create an EXO system.
Signal types
All signals that are accessible from a SCADA system are described in this document. The signals that have a default value
are parameter settings that can be changed from SCADA. The signals without default values are actual values and cannot
be changed from SCADA.
EXOL type
EXOL type signals :
R = Real number with decimal point (Real) (-3.3E3S -3.3E38)
I = Whole number (Integer) (-32768 -32767)
X = Index (0 - 255)
L = Boolean (Logic) (0/1)
Modbus type
Modbus type signals :
1 = Coil Status Register (Modbus function = 1.5 and 15)
2 = Coil Status Register (Modbus function = 2 and 15)
3 = Holding Register (Modbus function = 3. 6 e 16)
4 = Input Register (Modbus function = 4)
Compatible Modbus functions :
1 = Read Coils
2 = Read Discrete Input
3 = Read Holding Register
4 = Read Input Register
5 = Write Single Coil
6 = Write Single Register
15= Write Multiple Coils
16= Write Multiple Registers
Max. 47 registers
A maximum of 47 registers can be read in one message.
Communication limits
The Modbus master must wait for a minimum of 3.5 charactertimes (4 ms at 9600 bps) between two messages. When
the Modbus master communicates with more than one Corrigo E controller on the same communication line (RS485), the
Modbus master must wait for a minimum of 14 charactertimes (16 ms at 9600 bps) between the answer and the first
question for the next controller.
The Corrigo E controller has a limit of 10 fast communications every 30 seconds, while other communications will have a
answering delay of approximately 1 second.
Scale factor Modbus
All real signals (decimal) have scale factor 10, except the time settings signals that have scale factor 100 and Air flow
signals that have scale factor 1 for Modbus communication. Integer, Index and Logic signals have scale factor 1.
Modbus activation
The Corrigo controller uses the same port for both Modbus communication and EXOline communication. If you try to
communicate with a Modbus-activated unit using E tool or another type of EXOline communication, the input port will will
automatically adapt itself after approx. one second. The port will remain in EXO-mode until 10 seconds of communication
inactivity have passed after which it will revert to Modbus mode.
ENGLISH
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