HP Pen Plotters - HP-IB History and Troubleshooting
What is HP-IB?
The Hewlett-Packard Interface Bus (HP-IB) provides mechanical, electrical, timing, and data compatibility among all devices adhering to the 1978 ANSI/IEEE-488 standard. You can connect several HP-IB devices and assign them unique "addresses."
HP-IB is similar to Centronics parallel in that data is sent 8 bits (1 byte) at a time. However, HP-IB uses software and dipswitch addressing techniques to ensure that each device on the bus receives only the data specifically intended for it. Using this addressing technique, alternate devices can be instructed to talk (send) or listen (receive). More than one device can listen at the same time, but only one device can be designated as a talker at any given time.
There are basically two modes of addressing the plotter: addressable and listen-only. In addressable mode, the plotter can function as a talker or as a listener, depending on the commands it receives from the computer. In listen-only mode, the plotter hears all activity on the bus, but it cannot talk.
ISSUE: Trouble communicating via HP-IB.
Follow the procedure below:
Perform a demo plot. If it does not work, have the plotter serviced.
Do you have an HP-IB interface connections and an HP-IB cable? If yes, check all connections to make sure there are no loose connections. Check to see if the plotter is daisy chained. The number of devices daisy chained should not exceed eight. If necessary, disconnect devices to be under the limit.
Do the addresses on the plotter and the sending device match? If the plotter works in "listen mode" (address 31) only, it is probably an address problem. The plotter is factory set to an address of 05. Be sure the plotter's address is different from the computer or other peripherals.
Try a different HP-IB cable to see if it is a cable problem. t
Try a different HP-IB device to see if it is a port problem.
Have the plotter serviced.
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