Warning word, parameter 540:
States whether there is a warning on the frequency converter in Hex. See
Warning word, extended status word and alarm word.
Extended status word, parameter 541:
States whether there is a warning on the frequency converter in Hex
code. See
Warning word, extended status word and alarm word.
Pulse count, parameter 544:
This parameter can be read out via the LCP display (009–012). When you
run with counter stop, this parameter enables you, either with or without
reset, to read the number of pulses registered by the device. The highest
frequency is 67.6 kHz, while the lowest is 5 Hz. The counter is reset when
counter stop is restarted.
Pulse input 29[Hz], parameter 545:
Gives a pulse frequency in Hz connected to terminal 29.
561
Protocol
Value:
FC protocol (FC PROTOKOL)
[0]
Metasys N2 (METASYS N2)
[1]
Modbus RTU
[3]
Function:
There is a choice of three different protocols.
Description of choice:
Select the required control word protocol.
For further information about using the Metasys N2 Protocol see MG91CX
and Modbus RTU see MG10SX.
570
Modbus parity and message framing
Value:
(EVEN/1 STOPBIT)
[0]
(ODD/1 STOPBIT)
[1]
(NO PARITY/1 STOPBIT)
[2]
(NO PARITY/2 STOPBIT)
[3]
Function:
This parameter sets up the drive’s Modbus RTU interface to communicate
properly with the master controller. The parity (EVEN, ODD, or NO PAR-
ITY) must be set to match the setting of the master controller.
Description of choice:
Select the parity that matches the setting for the Modbus master con-
troller. Even or odd parity is sometimes used to allow a transmitted word
to be checked for errors. Because Modbus RTU uses the more efficient
CRC (Cyclic Redundancy Check) method of checking for errors, parity
checking is seldom used in Modbus RTU networks.
571
Modbus communications timeout
Value:
10 ms - 2000 ms
100 ms
Function:
This parameter determines the maximum amount of time that the drive’s
Modbus RTU will wait between characters that are sent by the master
controller. When this amount of time expires, the drive’s Modbus RTU
interface will assume that it has received the entire message.
Description of choice:
Generally, the value of 100 ms is sufficient for Modbus RTU networks,
although some Modbus RTU networks may operate on a timeout value
as short as 35 ms.
If this value is set too short, the drive’s Modbus RTU interface may miss
a part of the message. Since the CRC check will not be valid, the drive
will ignore the message. The resulting retransmissions of messages will
slow communications on the network.
If this value is set too long, the drive will wait longer than necessary to
determine that the message is completed. This will delay the drive’s re-
sponse to the message and possibly cause the master controller to time
out. The resulting retransmissions of messages will slow communications
on the network.
4 Programming
VLT
®
Decentral FCD 300 Design Guide
114
MG.90.S1.02 - VLT
®
is a registered Danfoss trademark
4
