Parker TPDM User Manual page 125

Parker Hannifin Manufacturing Srl
FUNCTIONAL DESCRIPTION
The Pico-PLC program is scanned every 6.144 milliseconds. Based on this sampling, the
inputs are first read, then the two timers (Pr92, Pr93, b99.0 and b99.1) are updated, the user
program is scanned and finally outputs are updated. For this reason, both input reading and
output setting can vary by 6.144 ms with respect to the physical event. If the microprocessor
is overloaded with work (the operating mode is active, there are frequent serial requests and
the PLC program is long), it may take more than 6.144 milliseconds to scan the entire PLC
program (b231.5).
All the instructions of the Pico-PLC with the exception of the arithmetic instructions are
single bit instructions. The available stack has a depth of only one bit.
The LD (LDN) instruction loads the bit defined as an operand on the stack, while all the other
logical instructions work on the stack. Arithmetic instructions are executed only if the stack
bit is set to 1.
For user convenience, truth tables of logical operations are given below.
AND logical operation
bit A bit B
0 0
0 1
1 0
1 1
The respective negative operations ANDN and ORN follow the same logic except that the
negated value of the bit specified will be used.
9 bits from b90.7 to b90.15 are reserved on the PLC and can be stored. 14 additional bits from
b91.2 to b91.15 are available on the PLC but cannot be stored. They are always set to 0 when
the converter is powered on.
10 word parameters are also reserved. These are from Pr80 to Pr89. They can be stored and
used as 5 double word parameters just as the 13 parameters from Pr151 to Pr163. 7 of this 13
parameters can be reserved if the Encoder CAN function is actives (see par. "encoder CAN").
The pico-PLC includes 9 constants for arithmetic operations. These are from Pr71 to Pr79 and
can be the constants most used by normal applications.
Remember that the array of the parameters is increased to complete the new operative mode,
the parameters from Pr168 to Pr187 are available on the PLC but cannot be stored (N.B. the
parameters from Pr164 to Pr167 are reserved and the user can not modify these.
When the arithmetic operations (ADD, SUB, MUL, DIV) are used, the operators are assumed
to be words and are signed. If a double word operation is required, set b94.0 = 1 before the
operation itself. After the operation the PLC will automatically set this bit to 0. The
parameters Pr58...Pr69 and Pr110...Pr149 are treated as double words so that in an operation
such as [ADD 71 72 64] the result –1 will be written in the double word Pr64:65 without
having to set b94.0=1 before the operation. If Pr80=-1 and Pr81=0 the operation [ADD 80 72
64] will give the result Pr64:65=-1, while the same operation executed with b94.0=1 will
assume Pr81 as the high word of the double word Pr80:81 and the result will be
Pr64:65=65535. In the first case, operators other than Pr58...Pr69, Pr110...Pr149 are treated as
words, while in the second case they are treated as double words.
124
result
0
0
0
1
OR logical operation
bit A bit B
0 0
0 1
1 0
1 1
user's manual TPDM
result
0
1
1
1