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<< Click to Display Table of Contents >> SpecView: Write Line to file/printer |
  
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<< Click to Display Table of Contents >> SpecView: Write Line to file/printer |
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This is also known as 'The Line Writer'.
This Button/Strategy Controller Action will write a line of text allowing the writing of fixed text and SpecView variables into files. Files can be appended to or recreated each time.
Click the Visual Editor button to edit the line to be printed:
Either specify a filename to write to in the Filename box or use a SpecView Text variable from the list of currently defined Text variables for the filename.
NOTE: The filename must not contain spaces.
To write to a filename which is specified by the date, see below.
On some printers it is possible to print directly to the printer by setting the filename to the name of the printer, for example, 'LPT1:', or for a network printer '\\print server\epson' a Form Feed can be added to the end of the text using the Control Codes drop down menu, described below.
It is also possible to write to a COM port by setting the filename to, for example 'COM2:'.
Check the Append box to append to an existing file, or check the Replace box to overwrite or create a new file.
The Command box defines the line(s) to be written to the file. Any text can be entered together with variable names, which are added using the Choose button. These will be enclosed in a pair of percent signs, such as: %%varname%% and will be substituted at runtime. These enclosed strings are called Variable Substitutions.
The number of decimal places to be used for Numbers (with decimals) is specified in Preferences - Runtime under Line Writer DP. This setting will then apply to all Numbers (with decimals).
NOTE: The Line Writer requires that any variables you include in the %% items are on a screen (GDW) that is always open.
Otherwise the name of the variable followed by 'Val not found' will be displayed.
If instead of the value of a variable the file contains the error: Val not found then the problem is likely to be that the variable needs to be on an open GDW.
Certainly all SpecView Pre-defined variables or User Variables that are to by written to a file by the Line Writer need to be on an open GDW.
For instrument variables this is also important because the last known value for the variable must be available at the time the Line Writer needs to write the line. The Line Writer cannot read the value over comms because this may take several seconds (or minutes in cases of timeouts with bad comms). By putting the value on a GDW, SpecView will usually have the value available.
The line written always has a <CR> and <LF> automatically added to the end, but these can also be added at any point in the line to generate multiple lines.
Use the Control Codes drop down menu to add typical control codes such as <HT> (Horizontal Tab) but for the more obscure codes, type the decimal code into the Special Characters box and click Add Code. These codes may be required, for example, for printer control or for other non-SpecView software to pick up and process such as Visual Basic programs.
See below for a list of ASCII special characters (or search the web for 'ASCII character codes')
Dec Code Dec Code
00 NUL 16 SLE
01 SOH 17 CS1
02 STX 18 DC2
03 ETX 19 DC3
04 EOT 20 DC4
05 ENQ 21 NAK
06 ACK 22 SYN
07 BEL 23 ETB
08 BS 24 CAN
09 HT 25 EM
10 LF 26 SIB
11 VT 27 ESC
12 FF 28 FS
13 CR 29 GS
14 SO 30 RS
15 SI 31 US
To specify the Decimal Places written by the Line Writer
The default setting for decimal places for values written to a file using SpecView's Line Writer is specified using Line Writer DP on Preferences - Runtime
To set the decimal places for specific values written to a file using SpecView's Line Writer (if the default setting above is not appropriate for a value), then use CVTSETTINGS.INI
To write to a filename which is specified by the date
As already stated; the filename used by the Line Writer must not contain spaces, commas or colons.
The filename would contain spaces and commas if the date format was left as: '%A, %B %d, %Y' the date would be, for example: 'Wednesday, 7 January, 2014' and the spaces and commas would cause problems.
Therefore, in order to use the date for the filename, for example: %%SpecView.Date%%.CSV
to create, say: 14_006.CSV then the date format needs changing to: '%y_%j' from Preferences - Display.
To add some text as a prefix or suffix to the filename copy SpecView.Date into a Text User Variable and create another Text User Variable containing the prefix or suffix then use the Strategy Action Parameters: Math Function to add (concatenate) the Text variables together.
Making your own 'Log Files'
Making a form of .CSV file is easy with the Line Writer. These three separate Line Writer commands illustrate the concept - note the commas between the %% to cause commas to be output in the file.
Call the file, for example LOG.CSV, and append to it each time:
+LOG.CSV Time,Zone1,Zone2
+LOG.CSV %%SpecView.Time%%,%%Zone1.PV%%,%%Zone2.PV%%
+LOG.CSV %%SpecView.Time%%,%%Zone1.PV%%,%%Zone2.PV%%
Provided that the last 2 lines are done independently by the Strategy Controller, the file may look like this:
Time,Zone1,Zone2
12:10:34,560.1,580.0
12:11:34,560.2,579.9
The above example shows writing a CSV (Comma Separated Values) format file, just like SpecView's Log Reports.
The reason for using the Line Writer instead of Log Reports would be if a line was required to be written to the file only occasionally, for example, when a fault occurred.