Group 52: Standard Modbus - ABB ACS 400 User Manual

Group 52: Standard Modbus

The ACS 400 can be connected to Modbus fieldbus system. Parameters of this group are used to set
up station number, communication speed and parity. Parameters 5206 - 5215 are diagnostic
counters that can be used to debug the fieldbus system. Refer to "Standard Serial Communication"
on page 115 for more information.
Modifications of parameters in this group take effect on the next power-up.
Code Description
5201 STATION NUMBER
Sets the slave number for the ACS 400 in Modbus network.
Range: 1 - 247
5202 COMM SPEED
Defines the communication speed of the ACS 400 in bits per second (bits/s).
3 = 300 bits/s
6 = 600 bits/s
12 = 1200 bits/s
24 = 2400 bits/s
5203 PARITY
Defines the parity to be used with the Modbus communication. Parameter also defines the number of stop
bits. With Modbus communication, the number of stop bits is 2 with no parity bit, and 1 with even or odd
parity.
0 =
NONE
1 =
EVEN
2 =
ODD
5206 BAD MESSAGES
This diagnostics counter increases by one every time the ACS 400 finds any kind of communication error.
During normal operation, this counter hardly ever increases.
5207 GOOD MESSAGES
This diagnostics counter increases by one every time a valid Modbus message has been received by the
ACS 400. During normal operation, this counter is increasing constantly.
5208 BUFFER OVERRUNS
Longest possible message length for the ACS 400 is 32 bytes. If a message exceeding 32 bytes is received,
this diagnostic counter increases by one every time a character which cannot be placed in the buffer is
received.
5209 FRAME ERRORS
This diagnostic counter increases by one every time when a character with a framing error is received from
the bus.
• Communication speed settings of the devices connected in the bus differ.
• Ambient noise levels may be too high.
5210 PARITY ERRORS
This diagnostic counter increases by one every time when a character with a parity error is received from
the bus.
• Parity settings of the devices connected on the bus differ.
• Ambient noise levels may be too high.
ACS 400 User's Manual
48 = 4800 bits/s
96 = 9600 bits/s
192 = 19200 bits/s
103