EVCO S.p.A. EVDRIVE03 | User manual ver. 3.7 | Code 144EPDE374
Page 53 of 76
8 SERIAL COMMUNICATION
8.1 Preliminary information
It is possible to control the EVDRIVE03 driver by connecting it to a controller.
The controller sends information to the driver necessary for its correct functioning, and the driver responds with its
internal states, such as (for example) the pressure and temperature measurements, alarms, certain parameters, etc.
The connection methods available on the EVDRIVE03 are CANBUS, MODBUS RS-485, and MODBUS on the setting and
programming port, according to the model.
The protocol to be used for communication with the controller must be selected via parameter Enabling mode (Pr06).
See the “Errore. L'origine riferimento non è stata trovata.” section.
The EVDrive03 behaves as an expansion to read the analog inputs AI1 and AI2, read digital inputs and write the relay.
(Note that driving the relay by the controller completely bypasses its function set by parameter.)
8.2 CANBUS serial communication
The EVCO controllers primarily use a protocol based on CANbus for communication with controllable systems.
The exchange of data is based on a list of variables or parameters that the controller may send to the driver, and a list
of variables the driver sends to the controller to provide its state data, using the CAN Master tool.
The variables and parameters to be monitored should be selected from lists proposed by SW development according to
their own needs.
The protocol performs one send request every second and one receive request every second, which does not occur
simultaneously. Each send/receive request is done on a different node, thru the nodes on the network.
You can give a different timing of the individual entities. The levels selected are:
• Level INIT: the value is written (or read) only once when the controller detects a new node in the network. If
the node is disconnected and then reconnected the initialization is done again.
• Level LO: every 10 seconds is written (or read) one of the entities with this priority.
• Level HI: each 1 second is written (or read) one of the entities with this priority.
When you connect a device to the network, the controller read and write all entities without differentiating the
priorities. Once this step is completed for each node, entities with priority INIT will no longer be requested.
The refresh time of the single entity depends, therefore, both on its level and on the number of entities of the same
level and type (read / write).
The EVDrive03 status variables are:
AI1 type
AI2 type
Ai error timeout
FSM status (Stat)
Used SH control parameters set (SetS)
Measured SH (SH)
Used SH set-point (SpSH)
Measured aspiration temperature (Ts)
Measured evaporator pressure (Pe)
Calculated evaporator temperature (Te)
Unit uf measure in use (UdM)
Working hour (Pr40)
Control algorithm status (AlgS)
Alarm status (AlSt)
Configuration warning (CoWa)
Enable valve status (EnaS)
Request a reset status (ParS)
Resynchro request status (ResS)
Target position (Psp)
Current valve position % (PAtt)
Communication alarm enable status(Pa01)
Communication alarm delay (Pa02)
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