Controlli W500H, Руководство пользователя

Страница: 16 / 42

Rev. d 01/1 16 DMP052E
MODBUS COMMUNICATION
Through the ModBus protocol it is possible to supervise up to 255 groups of 4 equipments, for a
total of 1020 devices. The ModBus connection is carried out on the equipment with
IDL = 1
(Master) through the RS485 serial port. The values managed by supervision and those managed
by the controller menu are the same. The Bus Supervision address IBS (ModBus address) of the
single device must be set manually on the configuration menu. The default ModBus address is
i b S
= 1. The devices connected via LinkBus must have the same ModBus address of the
Master. For ModBus data address see the relevant Database documents supplied on demand.
The wiring path between the two most distant devices connected to RS485 serial must not exceed
1000 m.: we recommend to use a 24AWG or 26AWG twisted-pair cable and not to carry out star
connections.
The first and the last device must be terminated by a 120-Ohm ¼-Watt resistance.
If devices from different manufacturers are present on the same communication Bus, it is
necessary to respect the limits imposed and to be careful not to use the same ModBus addresses
of other devices. We recommend using a shielded cable for RS485 Bus if on the plant or inside the
switchboard are present power devices, always keeping the suitable distances and precautions
regarding signal wiring and power cables.
For ModBus address set up and outside compensation from supervision, see page 21.
USE OF SUPERVISION OUTSIDE SENSOR FOR COMPENSATION
If outdoor sensor on (USE=ON) is enabled, it is possible to perform compensation through a value
sent by communication bus (supervision). Practically it is a virtual sensor which can be used
instead of a physical sensor connected to SC terminals.
If, for example, on the whole plant there is only one sensor outside the building, this function allows
using its value on all controllers connected to the supervision. Likewise from supervision it is
possible to set a unique set point to the various devices connected.
Attention: parameter USE = ON disables SH humidity sensor on SSE channel (see page 15).
For outside compensation setup from supervision, see page 21.
ERROR SIGNALLING
The controller is able to signal two anomaly conditions, one depending from communication and
the other from Sensors. If a Communication ERROR is present, the Anomaly Led
@
blinks. It is
possible to have a communication fault when, for example, two equipments connected via LinkBus
use the same IDL address or in case of high noise on communication, which provokes faulty data
transmission. Inside switchboards, in presence of power devices (contactors, Inverters, UPS,
reactors, etc.),
we recommend to use shielded cables (both for sensors and Bus) to reduce
anomaly probability.
If a sensor anomaly occurs, the Anomaly Led
@
lights up. If both anomaly conditions occur, the
Led blinks. Once the Communication anomaly is cancelled, the Led remains on indicating the
Sensor ERROR.
For a correct operation the anomaly Led must be switched off.
The conditions, which most frequently produce anomalies, are:
- Sensor is no more present with enabled function
- Sensor outside the controller (shared with LinkBus) is not present
- Multiple devices have the same IDL address