Phonetics Sensaphone SCADA 3000, User Manual

Page: 177 / 336

Valid Sources Valid Destinations
Inputs Outputs
Outputs Ladder variables
Timers (preset & value) C Variables
Counters (preset & value)
Ladder variables
C variables
Diagnostics
Alarms
LADDeR LOGIC PROGRAm DeVeLOPmeNT
The SCADA 3000 Ladder Logic editor allows you to build, save, and load complex ladder
programs for use with the SCADA 3000 main unit and expansion modules. The ladder
program can run by itself or in combination with the C-Program. Specifications of the Ladder
Program include:
• 32K of Program memory (about 1000 instructions—note that Windows NT is
required if you plan to write programs of 500 or more instructions)
• 64 Timers
• 64 Counters
• 128 Floating Point variables
• 4096 bit variables
Note
: Remember that Bit variables are stored as part of a 16 bit word. There are
256 words.
The real-time status of Timers, Counters, Bits and Variables can be viewed and changed on the
C and Ladder Variables form
(Programming>Variables)
.
The unit will support up to 32K of compiled code. You may also store up to 32K of source
code (optional) in the unit. However, note that compiled code is usually about half the size of
the source code. Thus, if you have a ladder program which exceeds 16K compiled, you will
most likely not be able to upload its source code.
Conserving memory with Windows 95 and 98
From the main menu, select File and then Conserve WinResources . This feature conserves
Windows resources to allow large programs (more than 500 instructions) to be used. Under
Windows 95 and 98 it’s recommended that you select this, especially if you have a large ladder
program. Under Windows NT, deselecting Conserve WinResources will speed up program per-
formance.
STARTING A NeW LADDeR PROGRAm
To run the Ladder Editor, click on Control , then Ladder Editor from the Control Center menu
bar, or click on the Ladder button from the Control Center toolbar. To edit a program using
Input and Output descriptions from a specific SCADA unit, select the
OnLine
Program Mode
and choose a unit from the list. Click OK . This will allow the program to intelligently allow
you to select data points and check for invalid I/O addresses based on the programming in the
selected unit.
15-17
Chapter 15: Ladder Logic Programming