Carrier 42AM Regelungshandbuch Seite 42

7 - MONITORING
7.3.2 - RS485 connection close-up
The components required for connection to the remote and/or local ModBus supervision system are as follows:
- An asynchronous half duplex RS485 serial card in RTU mode, connected to each controller.
- A standard RS485/USB converter for connection to a PC (not supplied by the manufacturer). The converter can be connected to any
network RS485 card.
- An electrical network using an AWG20/22 shielded cable (not supplied by the manufacturer) comprising a twisted pair and shielding
with a max 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 the manufacturer).
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
42
XX7515390-03_CONTROL_11_2019_BOX_MONO_EC_42AM.indb 42 XX7515390-03_CONTROL_11_2019_BOX_MONO_EC_42AM.indb 42
Pin Description
1 GND
2 RX+/TX+
3 RX-/TX-
03/12/2019 11:11:29 03/12/2019 11:11:29