Modbus control frame – CIRCUTOR computer SMART III-Fast Series User Manual
Page 70
4�10�1� MODBUS CONTROL FRAME
The
Computer SMART III FASTcontrolstheCPC3iboardsusingtheMODBUSprotocol�
Inparticular,itsendsaframeevery200ms,using
Function 15:Nbitswrite�
Themessageisa"broadcast"message,i�e�,itwillbereadbyallboards,inanyaddress�
Theformatoftheframeisasfollows:
Address
Func-
tion
Direction
of 1st bit
No� of bits
No� of
bytes
Bits value
CRC
00
0F
0064
0040
08
DD0 to DD7 XXXX
Address: 00,Broadcast,alltheCPC3iboardsreceivealltheframes�
Function: 0F,Writefunction�
Direction of 1st bit: 0064,thedirectionofthe1stbitintheCPC3iboardis0x0064�
No� of bits: 0040,theframehas64bits�
No� of bytes: 08,groupedinto8byes�
Bits value: Themeaningofthe8bytesisdetailedin
CRC: XXXX,CRCcharacter�
Table 39: Meaning of the 8 bytes, DD0 - DD7�
Byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
DD0
-
thy3_np2
thy2_np2
thy1_np2
-
thy3_np1
thy2_np1
thy1_np1
DD1
-
thy3_np4
thy2_np4
thy1_np4
-
thy3_np3
thy2_np3
thy1_np3
DD2
-
thy3_np6
thy2_np6
thy1_np6
-
thy3_np5
thy2_np5
thy1_np5
DD3
-
thy3_np8
thy2_np8
thy1_np8
-
thy3_np7
thy2_np7
thy1_np7
DD4
-
thy3_np10 thy2_np10 thy1_np10
-
thy3_np9
thy2_np9
thy1_np9
DD5
-
thy3_np12 thy2_np12 thy1_np12
-
thy3_np11 thy2_np11 thy1_np11
DD6
-
thy3_np14 thy2_np14 thy1_np14
-
thy3_np13 thy2_np13 thy1_np13
DD7
-
thy3_np16 thy2_np16 thy1_np16
-
thy3_np15 thy2_np15 thy1_np15
thyn_npxmeansthyristornoftheblockorperipheralx(Thisnumberofperipheral,x,isthe
oneprogrammedintherotatingselectorforeachboard)�
NB:Theframeasksforthetransmissionofdatatothyristorsinupto16differentsteps,phase
byphase�The
Computer Smart III FASTregulatorhasamaximumof12outputs,soitdoes
notusethelast4stepsoftheframe�
70
Computer SMART III FAST
Instruction Manual