Chapter 17

LXY Family of Graphics Line­printers

Overview

The versatile LXY12 and LXY22 are medium-duty printing devices that combine the benefits of a dot-matrix printer and a plotter on many of Digital’s UNIBUS PDP-11 and VAX systems. When used as lineprinters, the LXY family is compatible with Digital’s other lineprinters, need no special software, and are supported by the RT-11, RSX-11, RSTS/E, and VMS operating systems. When used with Digital’s PLXY-11 and BCP graphics software packages, you have full access to all the LXY plotting capabilities. PLXY-11 is currently supported by Digital’s RT-11, RSX-11M, RSX-11M-PLUS, RSTS/E, and VME operating systems, while BCP is supported by the RSX-11M and VMS operating systems.

Designed for use during a standard eight-hour shift in scientific, industrial, and commercial marketplaces, the LXY family of graphics lineprinters accommodates complex, intricate designs. In addition, the LXY12 and LXY22 provide hardcopy output of designs formulated on a graphics terminal, combine text and graphics in a single report, and produce simple forms.

Plotting capabilities, made possible with the PLXY-11 graphics software package, include standard line drawings, (for example, graphs, histograms, and charts) along with plots requiring shaded or solid areas (for example, bar graphs). The BCP Barcode/Block Character software is ideally suited to industrial and distributive applications where products must be coded and labeled using preprinted stationery and/or gummed labels.

The freestanding LXY12 and LXY22 systems include a controller if required by the configuration, a cable for connecting the controller to the graphics lineprinters, a pedestal with basket and paper guide, and a choice of two software package – the PLXY-11 graphics software and the BCP barcode package.

The LXY12 produces high-quality output at speeds of up to 300 lines per minute when printing and up to 42.4 centimeters per minute when plotting. The LXY22, a higher-speed device than the LXY12, prints up to 600 lines per minute and plots up to 84.6 centimeters per minute. The PDP-11 and VAX Systems and Options Catalogs contain ordering information for different versions of the LXY family.

The following LXY series models are available.

After selecting the appropriate model graphics lineprinter, choose your software from the chart below.

Major Features

The LXY family’s main features are:

• Printing and plotting capabilities – Allows you to combine both text and graphics within a single document
• Overlapping dot-print technology – Creates excellent, uniform density print quality
• PLXY-11 graphics software package – Provides unique plotting capabilities for graphics, histograms and charts
• BCP Barcode/Block Character software package – Permits coding and labeling on preprinted stationery and gummed labels, as well as the creation of forms
• Standard programmable vertical forms unit – Operates under program control and allows slewing to top of form and slewing within a form to a preselected line
• Hammer bank print mechanism – Eliminates wear that occurs with single printhead printers

Printing and Graphics Features

In both the LXY12 and the LXY22, printing is accomplished by a bank of spring hammers. The LXY12 hammer bank has 44 hammers, while the LXY22 has 66. These hammers, mounted on a shuttle, are positioned horizontally at every third character position for the LXY12 and every second position for the LXY22. As the shuttle sweeps the hammers back and forth across the character positions, the hammers are activated at each position in which a dot is required. Each hammer prints a single dot.

Printing

The LXY family of graphics lineprinters achieves excellent print quality by overlapping dots of 0.05 centimeters (0.02 inches) in diameter, on a dot matrix of nine-by-seven dots or nine-by-nine dots, anywhere on a page. The nine-by-seven matrix enables the printer to overlap dots both horizontally and vertically resulting in solid-looking characters and lines produced with uniform density. The nine-by-nine matrix is used for lower case letters with descenders, such as the letters “p”, “q” and “y”.

Double-height characters, as well as underlining are standard features with the LXY12/LXY22.

The LXY12 produces high-quality print at speeds of up to 300 lines per minute, 240 lines per minute when underlining or printing lowercase characters with descenders, and 170 lines per minute for double-height characters.

High-speed output of 600 lines per minute is provided by the LXY22 and is suitable for draft and data printing. When underlining or printing lowercase characters with descenders, the output is 465 lines per minute. The LXY22 prints double-height characters at the rate of 320 lines per minute.

When used as plotters, the LXY plots up to 42 centimeters per minute (16.7 inches per minute), while the LXY22 plots up to 84.6 centimeters per minute (33.3 inches per minute). Since the LXY12 and the LXY22 print overlapping dots anywhere on the page, plots are always sharp and uniformly dense.

Character Sets

The LXY12/LXY22 prints the full 94-character printable ASCII set. Character form is electronically determined by codes stored in PROM devices, which are accessed by the received character codes. Up to 160 different characters may be printed by installing additional PROM devices. Optional character set PROMs includes EBCDIC, Katakana, Farsi, Arabic, Hebrew, Greek, Cyrillic and special character sets, such as OCR.

Characters are printed in a line up to 132 characters wide.

Paper

The LXY12/LXY22 accept continuous fanfold edge-perforated paper between 11.4 centimeters (4.5 inches) and 40.6 centimeters (16 inches) wide. They accept single- or multipart carbon forms and can produce up to six copies of multipart carbon forms, up to a maximum thickness of 0.06 centimeters (0.025 inches).

Operator Features

Controls and Indicators

Six controls and indicators are found on the front panel of the LXY family of graphics lineprinters.

Power On/Off Toggle Switch

This switch controls application of all power to the graphics lineprinter.

Power Indicator

When the POWER toggle switch is set to ON, power is applied to the graphics lineprinter and the indicator goes on.

Paper Advance Pushbutton

While held down, this button advances the paper at the slew rate.

Check Pushbutton/Indicator

When lit, this button indicates one of the following error conditions.

• Paper is not loaded properly.
• Paper has run out.
• Paper is jammed.
• Paper is torn.
• Cover is left open.
• Forms thickness adjustment lever is left up.
• Any internal supply voltage is abnormal.

The light goes out when the fault is cleared. After reloading paper, press the CHECK button and the light will go out.

Top of Form Pushbutton/Indicator

This advances the paper to the top of the next form, or to the top of the form specified by the EVFU, if loaded. This switch operates only when the printer is off-line.

8LPI Pushbutton/Indicator

This switch selects either eight lines per inch (lit), or six lines per inch (unlit). This button operates only when the printer is off-line.

On-Line Pushbutton/Indicator

This switch enables or disables printer control through the interface. When the switch is lit, the interface is enabled. The printer cannot not go on-line if the CHECK indicator is lit.

Operation

The LXY12 and the LXY22 have two internal registers: the Control and Status Register (LXCS) and the Data Buffer Register (LXDB). (Refer to Appendix J.)

When the READY bit in the control and status register is set, the graphics lineprinter is ready to accept a character from the processor.

The processor loads characters one by one into the data buffer register in the controller. The controller then transfers the characters to a 132-character data buffer in the graphics lineprinter. The line length of 132 characters corresponds directly to this 132-character data buffer.

The current data buffer register (LXDB) contents are automatically printed out whenever either of the two control codes (Line Feed, Form Feed) is recognized. The Line Feed (LF) code advances the paper one line while the Form Feed (FF) code advances the paper to the top of the next page. If neither of these control codes is recognized, the contents of the data buffer will automatically be printed out when it is full.

An Elongate code (010₈) anywhere in a line of characters, causes the entire line to be printed double-height. To underline certain characters in a line, a Carriage Return (CR) code (015₈) is sent following the line of characters, which causes the lineprinter to wait for a line of control characters specifying which of the characters in the line already sent are to be underlined. Unlike the Elongate code which causes an entire line to be printed double-height, the Carriage Return code causes only those characters specified to be underlined.

The Electronic Vertical Format Unit (EVFU) allows you, under program control, to use a variety of form lengths. By specifying a number of lines at the slew speed, you can skip to a preassigned point in the form specified by the VFU channel number. Forms may be as long as 132 lines at six lines per inch.

A Plot Mode code (005₈) anywhere in a line of characters causes the lineprinter to plot the entire line instead of print. When plotting, only one row of dots is printed at a time, and the paper advances only one dot row with each Line Feed code (012₈). The characters are printed as a stream of binary bits; that is each 1 bit prints as a dot and each 0 bit prints as a blank dot space.

Special Nonprinting ASCII Control Codes

More information on this subject can be found in Appendix A.

Elongate (010₈)

The Elongate code, sent anywhere in a line of characters, causes the entire line to be printed double-height.

Carriage Return (015₈)

The Carriage Return code is used for underlining. It causes the lineprinter to wait for a line of control code characters (Underline, Delete or Space) before printing out the line of characters already in the data buffer register. Each control code character sent corresponds to a data character currently in the data buffer register. An Underline (137₈) control code character causes the lineprinter to underline the corresponding data character. A Delete (177₈) control code character causes the lineprinter to replace the corresponding data character with a blank space, and a Space (040₈) control code character causes the lineprinter to print the corresponding data character unchanged.

Shift Out (016₈)

The Shift Out code causes all subsequent characters to be selected from the optional character set on the PROM currently in use.

Shift In (017₈)

The Shift In code causes all subsequent characters to be selected from the ASCII character set. A Shift In is automatically generated at the end of every line.

Shift to 8 LPI (006₈)

The Shift to 8 LPI code causes the next Line Feed code (012₈) to advance the paper one-eighth of an inch for eight lines per inch spacing instead of the standard six lines per inch. The lineprinter automatically resets itself to 6 LPI after the Line Feed operation. Shift to 8 LPI is only operational when the 8 LPI switch on the lineprinter is set to 6 LPI.

Plot Mode (005₈)

The Plot Mode code (005₈) sent anywhere in a line of characters causes the lineprinter to plot the entire line instead of printing ASCII characters. There are 1,583 dot positions across the width of the paper, that is, 12 dot positions for each of the 132 characters. Plot Mode allows the printing of only the odd-numbered dots or six dots per character. Bits 0-5 of each character correspond to the six printable dots of that character space. The characters are printed as a stream of binary bits; that is each 1 bit prints as a dot and each 0 bit prints as a blank dot space. For instance, printing 101₈ (01 000 001₂) causes only dot number 1 to be printed for that character; printing 102₈ (01 000 010₂) prints dot number 3; and printing 055₈ (00 101 101₂) prints dot numbers 1, 5, 7 and 11. Codes 100₈-137₈ must be used instead of codes 000₈-037₈, which cannot be used to plot data because they are control codes and will be interpreted as such, that is, Line Feed (012₈).

Double Density Plot Mode (004₈)

The Double Density Plot Mode (DDPM) code allows printing of all of the even dot positions. A DDPM code sent anywhere in a line of characters causes the lineprinter to plot the entire line instead of printing ASCII characters. Double Density Plot Mode allows the printing of only the even-numbered dots or six dots per character. Note that the Line Feed code at the end of the line of characters does not cause the paper to advance. The DDPM code must always be followed by a Plot Mode Code (005₈), which fills in all of the odd-numbered dot positions.

Start Load (036₈)

The Start Load code initializes the EVFU and causes all subsequent characters to be loaded into the EVFU buffer.

Stop Load (037₈)

The Stop Load code indicates the end of the characters to be loaded into the EVFU buffer. The EVFU buffer allows storage of a Vertical Tab Stop code (channel) for each line of the form. Forms may be up to 132 lines long. Vertical Tab Stops are codes 020₈-035₈. A Vertical Tab Stop code sent anywhere in a line of characters causes the paper to advance to the next PVFU line indicated by that Vertical Tab Stop code at the next Line Feed code. Top of Form code 020₈ is always loaded into line 1 in the PVFU buffer.

Interrupts

The LXY12/LXY22 system controller uses bus request (BR) interrupts to gain control of the UNIBUS to perform a vectored interrupt, which causes the program to branch to an interrupt service routine. A BR interrupt can occur only if the INTERRUPT ENABLE bit in the control and status register is set. Once the INTERRUPT ENABLE bit is set, an interrupt request is generated whenever either the READY or ERROR bits in the control and status register is set.

When the READY bit is set, the graphics lineprinter is ready to accept a character to be loaded into the data buffer register (LXDB). When the ERROR bit is set, it indicates that some error condition exists. In this case, an interrupt is generated to cause the program to branch to an error-handling routine.

The interrupt priority level is 4 and the interrupt vector address is 200. Note that the priority level can be changed with a priority plug, and the vector address can be changed by jumpers in the interrupt control logic. However, any of Digital’s programs or other software referring to the priority level or interrupt vector address must also be changed if the priority plug or the vector address is changed.

Maintenance

Quality assurance means long life expectancy, high-quality output, and continuous smooth performance by your LXY graphics lineprinter. Special design features of the LXY family of lineprinters give these systems qualities of high reliability as well as ease of maintenance.

• The LXY12 and the LXY22 use hammer-bank print mechanisms and are therefore not susceptible to the wear of single-head matrix printers.
• The hammers seldom require adjustment or alignment. The hammer-bank module can be easily removed since it is held in place by two screws.
• Less chance of paper jams than with charaband printers since the paper moves as it prints. As the paper advances each successive line of dots overlaps to form solid-looking characters.
• Fewer moving parts than charaband and drum printers and 50 percent fewer components than mechanical font printers.
• Modular construction enables parts to be quickly removed and replaced during routine servicing and maintenance.
• The LXY12 and the LXY22 freestanding unit is designed to give stable, quiet operation below 65 dB.

Self-test procedure

Depressing the CHECK and PAPER ADVANCE buttons simultaneously causes the LXY series of graphics lineprinters to print lines of “E”. This continues as long as you hold the buttons down. If lines of “E” fail to print, contact your local Digital field service representative for assistance.

Additional Documentation

The following documents contain more detailed information about the LXY family of graphics lineprinters.

LXY Printer User’s Guide (EK-LXY22-UG)

tells you how to use, maintain, troubleshoot and configure the LXY family.

LXY Installation Guide (EK-LXY22-IN)

tells you how to install, maintain, troubleshoot and configure the LXY family.

Also of interest are:

PDP-11 and VAX Systems & Options Catalogs

Provide you with the most accurate and up-to-date information on currently available PDP-11 and VAX systems, options, and software products. This document is designed to help you select the right Digital product. European versions are also available.

If you require information not contained in these documents, contact your local Digital representative, dealer, or distributor.

Specifications

Performance Characteristics

Paper

Communications

Power Requirements

Operating Environment

Physical Characteristics