Delta Electronics Programmable Logic Controller DVP-PLC - Manual (Page 439)

8 Application Instructions API 100-149
DVP-PLC Application Manual 8-37
API Mnemonic Operands Function
126 D LOG P
Logarithm of Binary Floating Point
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
1
* * *
S
2
* * *
D *
DLOG, DLOGP: 13 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
1
: Device for base S
2
: Device for operation source D: Device for operation result
Explanations:
1. See the specifications of each model for their range of use.
2. Flags: M1020 (zero flag); M1021 (borrow flag); M1022 (carry flag)
3. This instruction performs “log” operation of the content in S
1
and S
2
and stores the result in D.
4. Only positives are valid for the content in S
1
and S
2
. When designating D registers, the data should be 32-bit
and the operation should be performed in floating point system. Therefore, S
1
and S
2
should be converted into
floating point values.
5. S
1
D = S
2
, D = ? Log
S 1
S
2 = D
Example: Assume S
1
= 5, S
2
= 125, D = log
5
125 = ?
S
1
D = S
2
5 D = 125 D = log
5
125 = 3
6. If the absolute value of the result ＞ maximum floating point available, the carry flag M1022 = On.
7. If the absolute value of the result ＜ minimum floating point available, the borrow flag M1021 = On.
8. If the result = 0, the zero flag M1020 = On.
Program Example:
1. When M0 = On, convert (D1, D0) and (D3, D2) into binary floating points and store them in the 32-bit registers
(D11, D10) and (D13, D12).
2. When M1= On, perform log operation on the binary floting points in 32-bit registers (D11, D10) and (D13, D12)
and store the result in the 32-bit register (D21, D20).
3. When M2 = On, convert the binary floating point (D21, D20) into decimal floating point (D30 × 10 [D31] ) and store
it in register (D31, D30).
M0
RST M1081
M1
D10 D12
M2
DEBCD D20 D30
D2 D12
D20
DFLT
DFLT
DLOG
D0 D10
Remarks: