Running an HP7475A plotter on the HP-IL Loop

[Richard L. Taylor]

Hi; I am working on a computer project. It involves the Hewlett Packered HP41cx handheld computer. I would like to use my HP41CX to drive my HP7475A plotter that has an HP-IB interface. I have the following items:

1.  HP41CX

2.  HP 5061-5238 PLOTTER MODULE

3.  HP 82160A HP-IL I/O MODULE

4.  HP 82183A EXTENDED I/O MODULE

5.  HP 82169A HP-IL / HP-IB INTERFACE UNIT

6.  HP 9114B  3.5 INCH FLOPPY DRIVE

7.  HP 82161A DIGITAL CASSETTE DRIVE WITH MINI CASSETTES

8.  HP 82162A THERMAL PRINTER

9.  A NUMBER OF HP-IL CABLES

10. HP 7475A PLOTTER WITH AN HPIB INTERFACE

11. L-com CMP SERIES - IEEE - 488 GPIB CABLE TO CONNECT THE PLOTTER TO THE HP-IL / HP-IB INTERFACE UNIT

The HP-IL loop works just fine with the floppy drive, cassette drive and the printer. I just can't get any response from the plotter. The plotter is on the end of the HP-IL loop

3.5 INCH FLOPPY DRIVE                    =  HP-IL address 1

DIGITAL CASSETTE DRIVE                 = HP-IL address 2

THERMAL PRINTER                             = HP-IL address 3

HP-IL / HP-IB INTERFACE UNIT      = (HP-IL ?) address 4 ---- Here I set the dip switches

PLOTTER                                              = (HP-IL ?) address 5 ---- Here I set the dip switches

I have tried every thing that I can think of to get the plotter to responed to the HPGL commands sent through the HP41cx and no luck. I tried Sending the HPGL commands with or with out an ESC character (ascii no. 27) with the HP-IL command OUTA. Can any one help me with this? I would be very greatful.

[Garth Wilson]

I have done tons of I/O with the 41cx through multiple instruments on the other side of the 82169A HPIL-to-HPIB interface converter, although not in recent years, and not with the plotter. Can you post some 41cx code? Did you put it in MANIO and use SELECT to select the plotter's address? Does the plotter seem to respond to the IN (initialize) command? Do you have the plotter manual?

As I remember, setting the DIP switches on the 82169A is only necessary if the controller is on the HPIB side. I don't think I ever touched them for controlling it from the HPIL side. If the plotter is at address 5, its DIP switches will be set to 00101. The plotter can have any address above the 82169A's address though. It does not have to be 5. After you get onto HPIB, the addresses do not have to be consecutive.

This is a continuation of the topic on TOS --> forum --> HPIL --> "Using an HP7475 plotter that has an HPIB interface."

[Tony Duell]

I think the problem may be the DIP switch settings on the HP82169 interface.

What you want to do is set the 82169 to 'translator' mode, not 'mailbox' mode. The latter is for use when you have a controller (such as a computer or calculator) on both the HPIL and HPIB sides.

The simplest configuration has the 82169 as the last device on the HPIL loop -- that is the 'output' connector of the 82169 goes back to the calculator. Then set the plotter (or other HPIB devices) address switches to a number higher than the number of HPIL devices (here, you need to set it to 5 or higher). And then simply address the plotter as that device from the HPIL side.

I've never tried a 7475 plotter, but I've had no problems runnign a 7440 Colorpro plotter this way, using the HP41 plotter ROM.

[Richard L. Taylor]

Tony, I wonder if my plotter problem is with the plotters handshake parodical. I have the plotters HP-IB manual. I don't understand the handshake parodical commands
Also, I wonder if it has something to do with the HP41cx flag 53 the I/O flag. I can"t work on this project to much because of my health ( chronic pain) in my shoulders.