BEKA BA488C Operating instructions

Issue 6
5October 2009
Serial text display
Programming Guide
[Version 3.4 Firmware ]

This guide applies to the following models:
BA488C - Panel mounted, Intrinsically Safe
BA484D - Field mounted, Intrinsically Safe
BA688C - Panel mounted, Safe Area
BA684D - Field mounted, Safe Area

Contents
Introduction ...................................................................................................................................................................... 1
What’s in this Programming Guide............................................................................................................................. 1
What’s in the Instruction Manuals.............................................................................................................................. 1
What’s in the Modbus Interface Guide ....................................................................................................................... 1
Other sources of information....................................................................................................................................... 1
Enhanced Features ...................................................................................................................................................... 2
Instrument Features ......................................................................................................................................................... 3
Display .......................................................................................................................................................................... 3
Switch Inputs................................................................................................................................................................ 3
Switch Outputs ............................................................................................................................................................. 3
Afew words about Modes… ............................................................................................................................................ 4
Display Features ............................................................................................................................................................... 5
Write Modes.................................................................................................................................................................. 5
Background Modes ...................................................................................................................................................... 6
Frames ............................................................................................................................................................................... 7
Active and Visible Frames ........................................................................................................................................... 7
Saved Frame Locations................................................................................................................................................ 8
The BEKA Protocol.......................................................................................................................................................... 9
Command format ....................................................................................................................................................... 10
Response format......................................................................................................................................................... 10
Key Mode 0 (Default) ........................................................................................................................................ 10
Key Mode 1........................................................................................................................................................ 10
Key Mode 2........................................................................................................................................................ 11
Operational Modes ..................................................................................................................................................... 11
CRC Generation ......................................................................................................................................................... 11
Multidrop Operation: ................................................................................................................................................. 12
Graphics Transfers......................................................................................................................................................... 13
File Format ................................................................................................................................................................ 13
Downloads .................................................................................................................................................................. 13
Uploads ....................................................................................................................................................................... 14
Standard Screens ............................................................................................................................................................ 15
Cyclic Data ...................................................................................................................................................................... 16
Basic Concepts ........................................................................................................................................................... 16
Updating using ASCII values .................................................................................................................................... 17
Updating using Binary Data...................................................................................................................................... 17
Data Timeout.............................................................................................................................................................. 17
Mapped Variables........................................................................................................................................................... 18
Scripting & Pattern Matching....................................................................................................................................... 18
Command Summary ...................................................................................................................................................... 19
Screen Handling & Text ............................................................................................................................................ 19
Attributes .................................................................................................................................................................... 20
Pixel Graphics ............................................................................................................................................................ 20
Line Graphics ............................................................................................................................................................. 21
Mapped Variables....................................................................................................................................................... 21
System ......................................................................................................................................................................... 22
Scripting ..................................................................................................................................................................... 23
Command Reference ...................................................................................................................................................... 24
<..> Command ............................................................................................................................. 25
<AFn> Active Frame........................................................................................................................ 26
<BDy,x,l> Box Draw ............................................................................................................................. 27
<BMn> Background Mode................................................................................................................ 28
<CA> Centre Align ......................................................................................................................... 29
<CCn> Check Code .......................................................................................................................... 30
<CD> Cyclic Data .......................................................................................................................... 31

<CE> Configuration Enable........................................................................................................... 32
<CI> Command Implement ........................................................................................................... 33
<CLn> Clear Line ............................................................................................................................ 34
<CMy,x> Cursor Move ........................................................................................................................ 35
<CP> Configuration Prohibit......................................................................................................... 36
<CRn,m> Cyclic Redundancy Check.................................................................................................... 37
<CS> Clear Screen......................................................................................................................... 38
<CTn> Cyclic Data Timeout ............................................................................................................ 39
<CVn,string> Cyclic Variable .................................................................................................................... 40
<CW> Clear Window ...................................................................................................................... 41
<DBn,m,p,q,r> Define Bargraph .................................................................................................................. 42
<DDn,m> Define Decimal .................................................................................................................... 43
<DFn> Download Font .................................................................................................................... 44
<DG> Download Graphic............................................................................................................... 45
<DLn,m,p> Define Limit ......................................................................................................................... 46
<DS> Download Screen ................................................................................................................. 47
<DTn,string> Define Tag............................................................................................................................ 48
<DUn,string> Define Units ......................................................................................................................... 49
<DVn,m,p,q,r> Define Variable.................................................................................................................... 50
<DWyt,yb,xl,xr> Define Window..................................................................................................................... 51
<EBn> Erase Bargraph.................................................................................................................... 52
<EF> Enable Flashing ................................................................................................................... 53
<EL> Erase Line ............................................................................................................................ 54
<EVn> Erase Variable ..................................................................................................................... 55
<F1> Font 1................................................................................................................................... 56
<F2> Font 2................................................................................................................................... 57
<F3> Font 3................................................................................................................................... 58
<F4> Font 4................................................................................................................................... 59
<F5> Font 5................................................................................................................................... 60
<FL> Flashing ............................................................................................................................... 61
<FR> Font Restore......................................................................................................................... 62
<FS> Fill Screen............................................................................................................................ 63
<FW> Fill Window.......................................................................................................................... 64
<GBn> Graphic Block ...................................................................................................................... 65
<HBn,m> Horizontal Bargraph............................................................................................................ 66
<HC> Home Cursor........................................................................................................................ 67
<HRn,m,p> Horizontal Rotate................................................................................................................. 68
<HSn,m,p,q,r,s,t> Horizontal Scroll .................................................................................................................. 69
<IF> Inhibit Flashing.................................................................................................................... 70
<KF> Keep Fonts ........................................................................................................................... 71
<LA> Left Align.............................................................................................................................. 72
<LF> Line Feed ............................................................................................................................. 73
<LHx,l> Line Horizontal .................................................................................................................... 74
<LN> Line New .............................................................................................................................. 75
<LVy,l> Line Vertical......................................................................................................................... 76
<MCn> Make Connection ................................................................................................................. 77
<NA> No Align ............................................................................................................................... 78
<NL> No Linefeed .......................................................................................................................... 79
<NS> New Screen........................................................................................................................... 80
<NU> No Underline........................................................................................................................ 81
<ODn> Output De-energised............................................................................................................ 82
<OEn> Output Energised ................................................................................................................. 83
<PM> Pixel Mode ........................................................................................................................... 84
<RA> Right Align ........................................................................................................................... 85
<RB> Reboot .................................................................................................................................. 86
<RC> Release Connection.............................................................................................................. 87
<RFn> Restore Frame...................................................................................................................... 88
<RLn> Restore Logo ........................................................................................................................ 89
<RM> Row Mode ............................................................................................................................ 90
<RS> Request Status ...................................................................................................................... 91
<SAn> Speed Adjust......................................................................................................................... 92
<SBn> Set Backlight ........................................................................................................................ 93
<SD> Screen Defaults .................................................................................................................... 94

<SFn,m> Save Frame .......................................................................................................................... 95
<SHn> Status Hide ........................................................................................................................... 97
<SL> Save Logo............................................................................................................................. 98
<SOn> Screen Option....................................................................................................................... 99
<SSn> Screens to Scroll ................................................................................................................ 100
<ST> Steady................................................................................................................................. 101
<SVn> Show Variable.................................................................................................................... 102
<SW> Smart Wrap ........................................................................................................................ 103
<TOn> TimeOut ............................................................................................................................. 104
<TW> Text Wrap........................................................................................................................... 105
<UE> Upload Enable ................................................................................................................... 106
<UL> UnderLine .......................................................................................................................... 107
<US> Upload Screen.................................................................................................................... 108
<VBn,m> Vertical Bargraph .............................................................................................................. 109
<VFn> Visible Frame..................................................................................................................... 110
<VLn> Variable Last...................................................................................................................... 111
<WMn> Write Mode......................................................................................................................... 112
<WSn> Write Soft character ........................................................................................................... 113
<WTstring> Write Text........................................................................................................................... 114
Advanced Commands................................................................................................................................................... 115
Scripting Control Commands .................................................................................................................................. 115
Script Commands ..................................................................................................................................................... 115
Pattern Matching Commands .................................................................................................................................. 116
Scripting ........................................................................................................................................................................ 117
Overview ................................................................................................................................................................... 117
Downloading and controlling scripts....................................................................................................................... 117
Operation with BEKA protocol................................................................................................................................ 117
Operation with Modbus RTU Protocol.................................................................................................................... 118
Script Flow ............................................................................................................................................................... 118
Key Handling............................................................................................................................................................ 119
Jump Register........................................................................................................................................................... 120
Delays and Waits ...................................................................................................................................................... 120
Events ....................................................................................................................................................................... 121
Script Event Update (Firmware 3.4 Onwards)........................................................................................................ 121
Timer Event (Firmware 3.4 Onwards) .................................................................................................................... 123
Script Errors ............................................................................................................................................................. 124
Script Timeout (Firmware 3.4 Onwards) ................................................................................................................ 124
Script Strings (Firmware 3.4 Onwards) .................................................................................................................. 124
Scripting Control Commands .................................................................................................................................. 126
Script Commands ..................................................................................................................................................... 127
Pattern Matching .......................................................................................................................................................... 129
Overview ................................................................................................................................................................... 129
Pattern Capture ........................................................................................................................................................ 129
Pattern Processing ................................................................................................................................................... 131
Responding to the host ............................................................................................................................................. 135
Packet Matching Commands ................................................................................................................................... 136

1
Introduction
This guide describes the BEKA Mode Protocol for the BA488C, BA484D, BA688C and BA684D Serial Text Displays.
This information is only required when programming a host to communicate with these displays; it is not required by
the end user. The target audience for this guide are software programmers with some experience in communicating with
ASCII devices. As the Modbus protocol is now natively supported (RTU slave only), connection to standard PLCs and
industrial computers is greatly simplified.
•For hardware installation information, please refer to the separate instruction manuals available for each
model.
•For an overview of how to use these displays on a Modbus system, please refer to the “Serial Text Display -
Modbus Interface Guide”.
The BEKA protocol is very straightforward, being loosely based on the principals of HTML. Simple text messages can
be displayed by using only a handful of commands. However, with a bit more perseverance, some quite advanced
displays can be created.
What’s in this Programming Guide
•Adescription of the instrument display
•An overview of the protocol
•Specific information on more advanced features
•Acommand summary, where the commands are grouped together by function and presented in a series of
tables
•Acommand reference, where each command is listed in alphabetical order and covered in detail. The
information is presented in a consistent layout and examples given to demonstrate the use of the command in
context.
What’s in the Instruction Manuals
•An overview of the instrument
•Intrinsic Safety Certification information
•System Design and Installation
•Configuration
•Programming Overview
•Maintenance
What’s in the Modbus Interface Guide
•An overview of the instrument
•Adescription of the memory map for the Modbus protocol
•Adescription of the various data types that are used
•Instructions on how to use the instrument in its standard non-programmed modes
Other sources of information
Our website at www.beka.co.uk has several files available to download:
•All of the examples in this guide
•Demonstration programs showing the capabilities of the display
•A‘Virtual Instrument’ – a PC based simulator that behaves exactly like the real thing. This can be used during
program development or to demonstrate the application to end users

2
Enhanced Features
This product is an enhanced version of our original Serial Text display (BA488C / BA484D) . It is compatible with all
existing applications as none of the existing commands have been altered.
The following features have been added as standard in the Version 3 firmware, released in July 2005:
Modbus Protocol
(RTU Slave Only)
This allows a display to easily be attached to most process control systems and
PLCs as a Modbus Slave. Registers are provided to control the display without
using the BEKA protocol commands and show the process variables on a
series of standard screens. However, more complex applications can be
implemented by using BEKA commands over the Modbus protocol.
Please see the “Serial Text Display – Modbus Interface Guide” for details.
Cyclic Data & Mapped Variables For ASCII serial devices without Modbus, a set of commands has been added
to allow the standard screens to be easily used. The addition of Mapped
Variables within the product makes it much easier to update displayed values
automatically, without the need for screen redraws.
Standard Screens A set of standard screens is included to display up to 8 parameters - no
programming is necessary.
Scripting The display can run through a set of commands independently of the host it is
attached to. This allows an application to be loaded into the display only once,
leaving the host free to perform other tasks.
Pattern Matching A fixed format data string from a dumb instrument can be decoded by the
display and the results shown on screen. This feature allows a local display to
be incorporated anywhere on the installation without using host resources.
Speed Increase A command has been added (SA) to increase the internal speed of the
Intrinsically Safe versions of the display at the expense of a reduction in
backlight intensity. Screen redraws are much faster, and more complex pattern
matching can be achieved.
Soft fonts storage There is now the ability to save Font 5 soft fonts.
The following features have been added as standard in the Version 3.4 firmware, released in September 2009:
Integer Variables Modbus variables can now be input as 16 or 32 bit integers in addition to
floating point format. This makes the display easier to interface to simpler
devices.
Script String Variables String variables have been added to make it easier to display operator
information.
Standard Screens Two more standard screens have been added to display 8 parameters - no
programming is necessary.
The following existing commands are now permitted in standard screen mode:
<CE>, <CP>, <OEn>, <ODn>, <SBn>.
Hide Unused Variables In applications where fewer than 8 variables are required, it is now possible to
hide unused values making it more intuitive for the operator.
Status visibility The ability to show or hide the data status has been added. This is useful when
the context of that information has the potential to confuse the operator.
Scripting Several more scripting commands have been added.
The safe area versions of the product are not limited by Intrinsically Safe power limitations, and will execute commands
approximately four times faster. They are also able to communicate with the host at speeds up to 115KBaud via RS485,
or up to 19.2KBaud via RS232
After reading through this guide, if you still have a problem getting the results you need then email us at
[email protected] and we will do our best to help you.

3
Instrument Features
Adetailed overview of the instrument is given in the instruction manual for each product. This should be read before
implementing any system using this instrument. However it is useful to summarise the main features of the display
before attempting to design any controlling software application.
Display
The instrument display is organised as 120 pixels horizontally by 64 pixels vertically. Each pixel is approximately
0.7mm square which makes it ideal for displaying text and simple graphics. The size of the pixels improves the contrast
and hence the readability at greater distances.
The display is also backlit by an ultra-efficient green LED module which enables the screen to be viewed in all
conditions, from bright sunlight to total darkness.
Switch Inputs
There are six switches on the front of the panel mounted instrument, and four on the field mounted instrument. Both
models have the option of overriding these with up to six external switches which can be sized and labelled to suit the
application.
Switch Outputs
There are two switch outputs available, which are under total control of the host. These are totally isolated and can be
energised or de-energised independently of each other.

4
Afew words about Modes…
It is worth reviewing the different modes that are referred to in this manual - these can become confusing if taken into
the wrong context!
Operational Modes Refers to the communication protocol between the host and the instrument
These can range from Mode 0 (the simplest) to Mode 4 (the most complex). This mode
essentially determines how much error checking is applied to the data during transmission.
See the Protocol section (Page 9) for a detailed explanation
Row and Pixel Modes Refers to the way text and graphics are positioned on the screen
The simplest and quickest mode is Row Mode – think of it as being able to position objects
on a page with ruled lines. In this mode the screen is split up into eight horizontal rows each
eight pixels high. Text is then aligned with these rows
Pixel Mode allows objects to be placed anywhere – but the drawback is that it takes a bit
longer for the display to be updated
See the <RM> Row Mode and <PM> Pixel Mode commands for further information
Write Modes Refers to the way text and graphics are written on the screen
Mode 0 is normal : objects appear as a black image on a clear background
Mode 3 is inverse : objects appear as a clear image on a black background
Modes 1 and 2 are more complex and are used for special effects
See the Write Mode section and also the <WM> command
Background Modes Refers to the image that appears when the screen is flashed
Atext or graphic object can be flashed against a clear background, a black background or an
inverse of that image
See the <BM> Background Mode, <FL> Flashing and <EF> Enable Flashing commands
Key Modes Refers to the format of the key-press data that is returned to the host.
Mode 0 is the simplest, where data is returned as a single byte describing the last key pressed.
Mode 1 also returns a single byte, but this time individual key status is returned as the six
least significant bits of this byte.
Mode 2 returns 6 individual bytes showing the status of each key as an ASCII 0 or 1
See the Response format section (Page 10)
The “Command Reference” section (Page 24) shows which modes are applicable to each command.

5
Display Features
Some powerful features are built into the display that allow relatively complex visual effects to be generated with only a
few simple commands. The command reference section of this programming guide has many examples of what can be
achieved with a little creativity and lateral thought.
One of the most important concepts to understand is the mechanism of writing to the display.
The display has a foreground and a background. Objects are written to the foreground by sending commands to the
instrument. The background is updated automatically, although commands are available to control what is actually
written there. These choices are described as the “Background Modes”
When an object needs to be written to the foreground there are a number of choices available that affect the appearance
of that object. These choices will also effect what is written to the background, so these choices are described as the
“Write Modes”
Write Modes
Anew object can be added to the screen in four ways, each being associated with a particular Write Mode. However,
the write mode is ignored in two cases where it is not considered appropriate, namely restored frames and bargraphs. In
these cases, changing the appearance of such items may render them meaningless.
The four modes are:
Write Mode 0 is the ‘normal’ method of updating the screen. The object is written to the screen where it over-writes
the current screen contents i.e. if a pixel is set on the new object being written, then the corresponding
pixel is set on the screen. If a pixel is not set on the new object, it is cleared on the screen
For example:
Existing NewObject Resultant
Screen tobewritten Screen
Display Display
Write Mode 3 is almost the same as Mode 0, except that the resulting image is the inverse of the new object. The object
is written to the screen where it over-writes the current screen contents i.e. if a pixel is set on the new
object being written, then the corresponding pixel is cleared on the screen. If a pixel is not set on the
new object, it is set on the screen
For example:
Existing NewObject Resultant
Screen tobewritten Screen
Display Display