Delta Electronics Programmable Logic Controller DVP-PLC - Manual (Page 421)

8 Application Instructions API 100-149
DVP-PLC Application Manual 8-19
API Mnemonic Operands Function
108 CRC P Checksum CRC Mode
Controllers
ES/EX/SS SA/SX/SC EH/SV
Bit Devices Word Devices Program Steps Type
OP X Y M S K H KnX KnY KnM KnS T C D E F
S *
n * * *
D *
CRC, CRCP: 7 steps
PULSE 16-bit 32-bit
ES EX SS SA SX SC EH SV ES EX SS SA SX SC EH SV ES EX SS SA SX SC EH SV
Operands:
S : Start operation device for RTU mode checksum n: Number of calculated bits D: Start device for storing the
operation result CRC checksum: See remarks.
Explanations:
1. Range of n: K1 ~ K256
2. Flags: M1161 (switching between 8/16-bit modes)
3. If n does not fall within its range, an operation error will occur, the instruction will not be executed, M1067,
M1068 = On and D1067 will record the error code H’0E1A.
4. In 16-bit conversion mode: When M1161 = Off, S divides its hex data area into higher 8 bits and lower 8 bits
and performs CRC checksum operation on each bit. The data will be sent to the higher 8 bits and lower 8 bits in
D . n = the number of calculated bits.
5. In 8-bit conversion mode: When M1161 = On, S divides its hex data area into higher 8 bits (invalid data) and
lower 8 bits and performs CRC checksum operation on each bit. The data will be sent to the lower 8 bits in D
and occupy 2 registers. n = the number of calculated bits. (All higher 8 bits in D are “0”.)
Program Example:
When PLC communicates with VFD-S series AC motor drives (In RTU mode, M1143 = On), (In 16-bit mode, M1161 =
On), the sent data write in advance H12 into H2000 of VFD-S.