Toshiba XLTR-200 사용자 설명서

 

  

44

This section will discuss topics that are specific to each of the available network 
selections. 
 
 

The gateway supports Modbus slave and master functionality via Modbus RTU.  
The slave implementations share common access methods, which is to say 
they support the same functions and reference the internal points via a 
common “Modbus Slave” holding register assignment.  Other notes of interest 
are: 
 
• 

Points are addressed by their assigned holding register (4X reference) via 
Modbus slave protocols. 

 
• 

Points can access both holding registers (4X references) and input 
registers (3X references) via Modbus master protocols. 

 
• 

Supported Modbus slave functions are indicated in Table 1. 

 

1 Read 

coils 

3 

Read multiple registers 

5 Write 

coil 

6 

Write single register 

15 

Force multiple coils 

16 

Write multiple registers 

 
 
• 

Register number entry radix is decimal (e.g. 10 = 10

10

) 

 
• 

Configuration tip: Improved network utilization may be obtained by 
appropriately grouping points into blocks having contiguous holding 
register assignments.  In this way, the “read multiple registers” and “write 
multiple registers” functions can be used to perform transfers of larger 
blocks of registers using fewer Modbus transactions compared to a 
situation where the read/write registers were arranged in an alternating or 
scattered fashion. 

 
• 

Because the transaction is handled locally within the gateway, write data 
checking is not available.  For example, if a write is performed to a register 
with a data value that is out-of-range of the corresponding “source port”