Serial Communications - Danfoss MCD3000 Series Manual

Serial communications

The MCD3000 has a non-isolated RS485 serial
communications link.
ATTENTION
Communications cabling should not be
located within 300mm of power cabling.
Where this cannot be avoided consideration should be
given to providing magnetic shielding to reduce
induced common mode voltages.
Data transmitted to and from the MCD3000 must be
in 8 bit ASCII, no parity, 1 stop bit.
Baud rate is set by Par. 22 Serial Communication -
Baud Rate.
The MCD3000 can be programmed to trip i f the
RS485 link fails. This is done by setting Par. 24 Serial
Communications - RS485 Time Out.
The starter address is assigned using Par. 23 Serial
Communications - Satellite Address.
The flow chart below shows how a host controller
would typically address the MCD3000.
MG.15.A2.22 – VLT is a registered Danfoss trademar
MCD3000 Series
The flow chart below shows how the MCD3000 would
typically respond to the host.
The following code sequences are used in the
communications between the host and the MCD3000
(network).
Address slave unit.
ASCII EOT [nn]
or 04h [n1]h [n2]h
Slave response.
ASCII ACK
or 06h
ATTENTION
If no MCD3000 starter is configured to the
specific slave address, no response will be
received by the host. The host software timeout
should be set to a minimum of 250 ms.
ATTENTION
Slave address must be two digit, addresses
less than 10 must have a leading zero (0).
LRC ENQ
[LRC1]h [LRC2]h 05h
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