CIAT 1-PH HEE BOX, Руководство по управлению

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7.3.2 RS485 connection close-up
Pin Description
1 GND
2 RX+/TX+
3 RX-/TX-
The components required for connection to the remote and/or local ModBus supervision system are as follows:
- An asynchronous half duplex RS485 serial card (code: PCOS004850 ) in RTU mode, connected to each pCO
3 controller.
- A standard RS485/USB converter for connection to a PC (not supplied by CIAT). The converter can be connected to any network
RS485 card.
- An electrical network using an AWG20/22 shielded cable (not supplied by CIAT) comprising a twisted pair and shielding with a
maximum length of 1000 m. This network must never run parallel to power cables at a distance of less than 50 cm . These cables
may cross, but perpendicularly. You are requested not to form a loop with the network cable or the earth braid, and to properly
separate the various cable families (control, power, earth and communication bus).
- A supervision program installed on a PC (not supplied by CIAT).
An 120 Ω ¼ W electrical resistor must be connected to the RS485 serial card in the last position on the bus, as shown in the
connection diagram.
The format of the data frame, which cannot be modified, is as follows: 8 data bits, 2 stop bits and without parity on 2 words
(2 bytes), high-order, low-order.
The data format (16 bits, signed) is standard for Modbus except for analogue data which is in the format "Integer divided by 10".
The codes for the ModBus functions used are:
- 1 or 2: Read n bits
- 3 or 4: Read multiple registers (16 bits)
- 5: Write one bit
- 6: Write one register
- 8: Read diagnostics counters
- 11: Read event counter
- 15: Write n bits
- 16: Write multiple registers (16 bits)
NB: The JBus addresses are equal to the "ModBus address" - 1
1-PH HEE BOX EN-24