18
NT935 ETH
ETHERNET MODBUS TCP OUTPUT
INTRODUCTION TO THE ETHERNET MODULE
The Ethernet connectivity of the new NT935 ETH allows you to implement the functions of the Tecsystem control units
directly into your monitoring system, with maximum 8 Modbus TCP nodes.
The integrated module includes all the essential network features, among which a 10Base T / 100Base-TX Ethernet
connection, TCP / IP full stack suitable to work as Modbus TCP slave.
The unit can be used for remote configuration, monitoring in real time or problem solving.
The Windows-based Telnet system allows configuring the NT935 ETH easily into a sub-network with specific IP
addresses.
OPERATING NOTES
The communication of the temperature control monitoring unit is active only when the NT935 ETH is in temperature
control mode (Scan, Auto, Man and T.Max).
When other functions such as programming, programming display and relay test are activated, the ModBus
communication is temporarily deactivated.
DATA TRANSMISSION
The Ethernet module allows you to connect to the control unit through Modbus TCP slave so that you can: read the data
on the Modbus table on page 20 and write those in the paragraph regarding the remote programming notes.
The ETH module is always in slave mode.
The NT935 ETH control unit is in communication with the network only when it is in temperature reading mode, while it is
inactive when in the following modes: display, programming and relay test.
NOTES ON ETHERNET ELECTRICAL CONNECTIONS
As to the signal cable to use in order to guarantee correct operation, it is necessary to use a CAT 7 Ethernet cable with
RJ45 connector with the following specifications:
4 twisted pairs 23AWG
Tinned copper braid with an 80% cover.
Always position the Ethernet cable far from power cables.
.
FUNCTION CODE
The ModBus module supports the following function codes:
3
(10)
:
- holding register reading
16
(10)
:
- register multiple writing
If ModBus receives a message and a CRC error is detected, no answer is given.
CODE 3
(10)
.
Request:
Slave address, code 3
(10)
, Starting address HI, Starting address LO, Number of Point HI, Number of Point LO, Crc LO, Crc HI.
Answer:
Slave address, code 3
(10)
, Byte count, Data HI, Data
LO……., Crc LO, Crc HI.
CODE 16
(10)
.
Request:
Slave address, code 16
(10)
, Starting address HI, Starting address LO, Number of Point HI, Number of Point LO, Byte count,
Data HI, Data
LO……., Crc LO, Crc HI.
Answer:
Slave address, code 16
(10)
, Starting address HI, Starting address LO, Number of Register HI, Number of register LO, Crc LO,
Crc HI.
