RSTi-OM User Manual
Section 11
GFK-3212A
Jun 2021
Modbus/TCP Interface
114
•
Controller Read access:
-
The PDI data from one or more ports may be read with one message. (i.e.: If
addressing port 1, at address 1000, ports one to four may be read in one message.)
-
The PDO data from one or more ports may be read with one message. (i.e.: If
addressing port 1, at address 1050, ports one to four may be read in one message.)
-
Partial PDI and PDO data reads are allowed.
-
The length of the Read message can range from 1 to the total, configured PDI or
PDO length for all ports starting at the addressed port.
•
Controller Write (Output) access:
-
Only PDO data may be written.
-
The PDO data for one or more ports may be written with one Write Holding Registers
message.
-
Partial PDO data writes are not allowed.
-
The length of the Write message must be equal to the total of the configured PDO
lengths for all ports to be written. The one exception is that the data length of the last
port to be written must be equal to or greater than the device PDO length for that port.
