TECHNICAL MANUAL
LARGE DISPLAYS DN109/NB - DN119/NB - DN189/NB - DN129/NB
CHAPTER 24
ETHERNET COMMUNICATION
24-12
Fig. 105: Message in MODBUS/TCP to send the characters "E 523".
As can be seen, as many registers as necessary are written. In this case, since the
number of characters is 5 (odd), 3 registers must be used, and the last byte must be set to 00h.
If this method is used, the color or light intensity of the display cannot be modified for
reasons of compatibility with previous products. It is possible to change the color by adding a
previous step to the message, first writing to any register associated with numerical values
(modifying the color) and then writing the message to register 00.
Coil Writing
In addition to the registers, with MODBUS/TCP it is possible to carry out the
“Write Multiple Coils” function to activate/deactivate the relays or set the flashing of the display.
They can also be modified with
“Write Single Coil”, but function 0Fh is used
in the examples for simplicity.
5 coils are established that can be activated or deactivated, starting from
START
ADDRESS 1
. In order, the coils are used to establish the following parameters:
•
Coil 1.
Activates or deactivates relay 0.
•
Coil 2.
Activates or deactivates relay 1.
•
Coil 3.
Activates or deactivates relay 2. (Relay 2 is available as an option)
•
Coil 4.
Activates or deactivates relay 3. (Relay 3 is available as an option)
•
Coil 5.
Activates or deactivates blinking.
All the coils are activated at “1” and deactivated at “0”. It is possible that your display
model does not have coils 3 and 4, in which case their value will not affect any functionality.
Example:
You want an alarm to be activated for a given value and the display to start flashing the displayed
value. For this it is necessary to activate one of the relays and the flashing of the equipment. In
this case, COIL1 must be activated to switch RELAY0 and COIL5 to activate the flashing.
Fig. 106: Example of display coils activation.
Reading of registers and
coils
The described displays allow the reading of both registers and coils.
The system works identically to writing, the desired registers or coils and their address
are selected to read the status.
It can be read with the MODBUS functions
“Read Holding
Registers”.
