B&B Electronics GW-7553 - Manual - Manual (Page 36)

GW-7553 PROFIBUS/Modbus TCP Gateway User Manual (Version 1.00, Dec/2008) PAGE: 36
Table 12 Input data area
Module Byte Data Description
Input
module
0~127 Data Receive data
4.6.2 Output data area and communication command
The maximum length of output data is 131 bytes. Before arrange the output
module, the user must arrange and configure the system setting module. The
first three bytes belong to communication commands, as shown in table 13. The
user can change data and I/O state of Modbus Slave device or DI/DO/AI/AO
data of GW-7553 by modify data of output module.
Table 13 Output data area
Bit Position
Module Byte
7 6 5 4 3 2 1 0
Description
0 Data output command
1 - - - - - - SM DC Control bit
System
setting
module
2 Output module select
Output
module
3~130 Output data
●
Data output command(byte 0)
a. When Modbus type is Master
When this byte is changed, PROFIBUS Master device will send data
of output module to DO/AO data of GW-7553 and then GW-7553
will send query message to Modbus Slave device for change data or
output state of Modbus Slave device.
b. When Modbus type is Slave
When this byte is changed, PROFIBUS Master device will send data
of output module to DO/AO data of GW-7553.
PS: When the user use this byte to trigger “data output command”, the
user must increase this byte in order (ex: 0->1, 1->2,…, 255->0) or else