22.10.1 D-Script/Global D-Script
Restrictions
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When using CF card or USB storage, check the
restrictions identified in the following.
 5.5.3 Restrictions on
External Storage Usage
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In D-Script
programming, three addresses occupy the same amount of memory as
one Part. The maximum number of addresses available for a D-Script
is 255. Total number of devices used in trigger expressions and
script programs. Use the fewest possible addresses, since the more
devices that are used, the slower the response.
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D-Script cannot run calculations on floating
point values (Float Variables or Real Variables).
You cannot run calculations on structured variables either.
However, you can run calculations on individual elements from
structure variables.
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The size of a D-Script affects the Display Scan
Time. Note that using a large number of addresses may significantly
degrade the program performance.
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The interval for the trigger bit ON/OFF status or
true/false condition must be longer than the communication cycle
time*1 or display scan
time*2, whichever is longer.
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Do not specify [Continuous Action], [While Bit is
ON], [While Bit is OFF], [While Condition is True], or [While
Condition is False] in the Trigger Conditions for the script to
write to device/PLC addresses. An error will be displayed because
the communication processing cannot keep up with the large amount
of write instructions.
To enable these trigger conditions, use the display unit's internal
device or temporary address.
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When there are multiple scripts registered with
[While Bit is ON], [While Bit is OFF], [While Condition is True],
or [While Condition is False] trigger conditions, and communication
with a device/PLC is terminated while the scripts are running, new
scripts will not execute. After communication is re-established,
the scripts run from the beginning of all the registered
scripts.
Even if the process was working on scripts set up on Window
screens, after communication is re-established, the scripts restart
from the beginning of the Base screen scripts.
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When calling a
function from a function, the maximum number of nested levels is 9.
Please do not set up more.
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Up to 9 levels of nested calls can be
created.
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Up to 254 Functions can be created.
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When a value is assigned to an address for
switching screens while a D-Script command is being executed, the
screen switching operation is processed after all D-Scripts have
been processed
For example,
ID:00000
Data Format = Bin, Data Length = 16 Bit, Sign = None, Trigger = Bit
ON ([b:M0000])
[w:[PLC1]D0100]=0 // (1)
[w:[#INTERNAL]LS0008]=30 // (2) Change to Base Screen 30.
[w:[PLC1]D0101]=1 // (3)
[w:[PLC1]D0102]=2 // (4)
When the above D-Script is executed, processing of the screen
switch is performed after (3) and (4) have been processed.
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When data used in a D-Script is set up with a
display unit's touch operation, make sure the data write operation
is complete before running the D-script.
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There is no differenciation between upper and
lower case for text in the parameters.
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You cannot use the following symbols.
" * : < > ? [ ] | ~ , = +
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In a D-Script or Global D-Script, when using a
device address where you define the access type, the instructions
and operators you can use are as follows.
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Offset Address
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Addition (+), Subtraction (-), Modulus (%),
Multiplication (*), Division (/), and Assignment (=)
Trigger Condition Operation List When Using
Memory Link and Other Devices
Depending on the devices specified for trigger conditions, the
D-script operations activated by a trigger after the screen changes
or the power is turned on are as follows:
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When using Global D-Script, the operations
mentioned above are performed only when the GP power is turned ON.
At the screen change, the above table is not applied, and the
trigger conditions are continuously monitored.
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When the trigger condition in D-script is set to
[Timer], a timer starts counting when changing to a screen with a
D-script.
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When the trigger condition in D-script is set to
[Timer], a timer starts counting when the display unit is turned
on.
Restrictions Specific to Global D-Script
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Global D-Script operation is suspended during
screen changes or other GP operations.
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After the display unit is turned ON, Global
D-Script actions are not performed until all data reads are
completed for the initial screen.
After the initial screen changes, Global D-Script actions may be
performed before the data reads are completed.
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The maximum number of devices in the Global
D-Script is 255. (Total number of devices used in trigger
expressions and script programs.)
When this number is exceeded, the D-Script does not function. Since
these devices always read data regardless of the screens, be sure
to use only the minimum number of devices required by your
D-Script. Otherwise, operation performance can be degraded.
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The maximum number of Global D-Scripts is 32. The
currently used function also counts as one Global D-Script. When
the number of Global D-Scripts reaches 32, any subsequent Global
D-Scripts are ignored.
Restrictions
for SIO Port Operations
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Addresses designated in the Send/Receive
functions are not added to the D-Script address count.
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The Control is a write-only variable, while
Status and Received Data are read-only variables. Reading the
Control variable or writing data to the Status variable causes the
operation to fail.
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Create independent D-Scripts (or functions) for
Send and Receive operations.
For information about transfer flow charts
22.5.3.1 Flow
Chart
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The User area in the LS device (LS20 to LS2031
and LS2096 to LS8191) can store data for Send/Receive
functions.
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In the [System Settings] workspace [Script I/O
Settings] page, when the [Type] is not set to [D-Script/Global
D-Script], the bit 13 in address LS2032 turns ON when the
[D-Script/Global D-Script] runs the [SIO Port Operation]'s Label
Settings functions (Send, Receive, Control, Read Status, and
Receive Data Size).
For information about special relays
A.1.1.3
Special Relay (Direct Access Method) or A.1.2.3
Special Relay (Memory Link)
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When using the Send/Receive functions, set the
bit length of the D-Script to 16 bits. Note that the operation
fails if the bit length is set to 32 bits.
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The size of the Send buffer is 2048 bytes, while
the Receive buffer is 8192 bytes. The ER signal (output) RS signal
(output) is turned OFF after at least 80% of the Receive buffer is
full of received data.
Limitations on BCD Format Operations
If a value which cannot be converted into BCD format is found
during operation, the program stops running.
These values include A to F in hexadecimal format.
If the program halts, bit 7 in the display unit's common relay
information (LS2032) turns ON. This bit does not turn OFF until the
display unit is turned OFF or enters offline mode.
For example,
[w:[PLC1]D0200]=([w:[PLC1]D0300]<<2)+80
If D300 is 3, shifting two bits to the left results in 0x000C,
which cannot be converted into BCD format, and interrupts program
execution.
[w:[PLC1]D0200]=[w:[PLC1]D0300]<<2
Unlike the above example, 0x000C is the result of the operation
to be stored in the memory, and does not cause the program to
stop.
Limitations of Zero Operations
If you divide by zero in division (/) and modulus (%)
operations, execution will stop. Do not divide by zero.
If the program halts, bit 8 in the display unit's common relay
information (LS2032) turns ON. This bit does not turn OFF until the
display unit is turned OFF or enters offline mode.
Notes on Delay During Assign Operation
Using a device address in an assign operation may cause write
delay because the display unit has to read the address data from
the connected device. Consider the following:
For example,
[w:[PLC1]D0200]=[w:[PLC1]D0300]+1 // ...1
[w:[PLC1]D0201]=[w:[PLC1]D0200]+1 // ...2
Statement (1) assigns (D0300+1) into D0200. However, in
statement (2), the result of statement (1) has not been assigned in
D0200 because of time-consuming communication with the device/PLC.
In such cases, program so that the result of statement (1) is
stored in the LS area before it is executed, as shown below.
[w:[#INTERNAL]LS0100]=[w:[PLC1]D0300]+1
[w:[PLC1]D0200]=[w:[#INTERNAL]LS0100]
[w:[PLC1]D0201]=[w:[#INTERNAL]LS0100]+1
Notes on dealing with negative numbers
For functions where a negative number is entered for an argument
that does not accept negative numbers*3, the entered number operates
as unsigned*4.
Cautions When Reading the Same Device Address
in the Same D-script
Even when the same device address is used in the same
D-script/global D-script, values read from the device address may
differ depending on the processing timing of D-script or global
D-script.
To avoid this situation, please program scripts to temporarily
store data in internal devices or temporary addresses.
Example
When Using Internal Device (USR Area)
[w:[#INTERNAL]USR20000]=[w:[#MEMLINK]0100]
[w:[#INTERNAL]USR00000]=[w:[#INTERNAL]USR20000]
[w:[#INTERNAL]USR00001]=[w:[#INTERNAL]USR20000]
When Using Temporary Address
[t:0000]=[w:[#MEMLINK]0100]
[w:[#INTERNAL]USR00000]=[t:0000]
[w:[#INTERNAL]USR00001]=[t:0000]
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