QUANTUM DI HEATER OPERATION / MAINTENANCE MANUAL PAGE 29
4.3.c Modbus/TCP
The heater can be operated over an Ethernet network using the
Modbus/TCP protocol. Although the heater can be controlled directly
using Modbus/TCP, Trebor recommends that the heater be controlled
using a communication library written by Trebor. The Trebor
communication library abstracts the details of Modbus/TCP. Currently,
the library is available for Win32 platforms. If you need the library for
another platform please contact the factory.
The IP address of the heater can be configured from the “Config” page
on the heater touch screen (see Section 4.2.e).
4.3.d Modbus Communication
Table 1: New Modbus Mapping and Table 2: Old Modbus Mapping
includes register mappings for single, dual, triple and quadruple output
Quantum heaters. For a standard single output Quantum heater use the
“Bank 1” addresses. Table 1: New Modbus Mapping and Table 2: Old
Modbus Mapping contains the name, address, type, data type, size, and
read/write permission for each register.
The Table 1: New Modbus Mapping interface to the Quantum heater is
composed entirely of Modbus registers – no Modbus coils are used. This
means that only two Modbus functions are required to communicate with
a Quantum heater. The function 03 (read holding registers) and function
06 (write single register) are the only two Modbus functions that will be
needed.
The Table 2: Old Modbus Mapping interface is an old interface that uses
both Modbus coils and registers. This interface is for backwards
compatibility with the first generation of Quantum heaters. New
installations should use the new register mapping found in Table 1: New
Modbus Mapping.
To turn the heater on remotely, the value 1 must be written to the
“Remote Heater Power” register. The heater must be in remote mode
(see Section 4.2.b) to enable remote on/off of the heater. To turn the
heater off remotely, the value 0 must be written to the “Remote Heater
Power” register.
All of the Boolean data type registers are false when they contain the
value 0 and true when they contain any value greater than 0. When
writing to Boolean registers, false is represented by the value 0 and true
is represented by the value 1.
The float data type registers need to be converted from network format to
host format after being read. If you are using SCADA software this will
be done automatically. If you are using the C or C++ programming
languages this can be done using the C function ntohl().
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