Instruction Manual

6.5.3 PCS MODBUS SLAVE CONTROL BYTES
The APB Setup Bytes, Control and Status Bytes, and applicable Error Code Bytes for Modbus
slave operation are provided in Tables 6-8 through 6-10. If any Control Byte is changed during
operation, it takes up to 10 seconds to become effective (there is a 10 second interval be-
tween PCS checks for setup changes.)
Table 6-8. APB Setup Bytes for PCS Modbus Slave
Title Definition Set
By
DDI-A DDI-B De-
fault
Mode It designates the APB communications functionality as
follows:
0 = Off, 3 = Modbus RTU Mode
This datapoint should be left at 0 and configured to
a 3 after all of the other control bytes are
configured because setting this datapoint causes
the Modbus PLC Interface functionality to start.
User B290 B456 0
Baud
Rate
It designates the data transfer rate as follows:
10 = 38400, 9 = 28800, 8 = 14400, 7 = 19200,
6 = 9600, 5 = 4800, 4 = 2400, 3 = 1200,
2 = 600, 1 = 300, 0 = 110
User B292 B458 0
Set-Up It designates the data format transfer protocol as
follows:
0 = 8 bits, 1 stop bit, no parity
1 = 8 bits, 1 stop bit, even parity
2 = 8 bits, 1 stop bit, odd parity
3 = 7 bits, 1 stop bit, even parity
4 = 7 bits, 1 stop bit, odd parity
5 = 7 bits, 2 stop bits, no parity
User B293 B459 0
Table 6-9. Control and Status Bytes for PCS Modbus Slave
Title Definition DDI-A DDI-B Set
By
De-
fault
Self
Address
It is the PCS slave address used to respond to all
messages.
B670 B646 User 0
Setup
Error
10 = Scan Time at 0. B684 B660 Soft-
ware
0
Scan
Time
It is the PCS time period for the read and write phases
of a PCS-PLC transaction. It is entered as a number
from 1 to 255 which represents 100 to 25,500 ms. (See
Section 3.7.)
B685 B661 User 0
Scan
Overruns
Counter*
This counter is incremented each time the read-write
phases exceed the specified Scan Time. It indicates the
Scan Time should be increased. (See Section 3.7.)
B686 B662 Soft-
ware
0
*User can reset by writing zeros into the datapoints.
53MC9015 53MC5000 PLC and Printer Interfaces
6-16
MODBUS2