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Technical Note: TN214-2

Setting the baud rate on the RTU8171

1200/2400 baud modification on Rev. 4 Boards only
(no modifications are needed for 4800/9600)

Open the RTU8171 enclosure and change capacitor C7 to .1uf 25V (104).

Rev. 5 Boards. Jumper E4

1-2 - 4800 / 9600 baud

2-3 - 1200 / 2400 baud

Modbus Protocol modifications

1. Up-load memory contents of S7-214/216 using MicroDOS or MicroWIN programming tools.

2. Edit the following line of code in SBR 63:

movb 16#8,smb30 9600 baud

(code already implemented)

 

movb 16#14,smb30 1200 baud

movb 16#10,smb30 2400 baud

movb 16#C,smb30 4800 baud

*Note- If using port 1 on the S7-216, edit the line of code movb 16#8,smb130 and set bit V1343.1

3. From the file menu compile/load memory to the PLC.

4. From the CPU menu copy program to memory cartridge.