HP 59309A HP-IB Digital Clock

[Vassilis Prevelakis]

The HP 59309A HP-IB Digital Clock allows access to a time of day clock via the HP-IB bus.

I have connected this thing to an HP-85 but have been unable to convince it to return a value.

I can send commends to the 59309A, (e.g. I can stop it and then restart it), but trying to read from it jams the bus, till I reset the bus (using the RESET 7 Basic command). The 59309A has a "ADDRESSED" LED that lights up when it sees its address on the bus. So when I send commands to it, the ADDRESSED LED briefly lights up, when I try to read from it, the ADDRESSED LED stays on till I reset the bus.

Assuming that the clock has address 17, the command I am trying is a simple:

ENTER 717; A

Behind an access cover under the display, are a few switches. The ones on the right serve to set the time and date, but the ones on the left are puzzling. There is a switch labeled INT/EXT, the clock works if it is set to INT, if the switch is set to EXT, the clock display goes out and the machine does not respond to commands sent over the HP-IB.

Another button labeled READ makes the display blink, but does not appear to do anything else.

BTW on the back of the machine there are 7 little switches, 5 are used to set the HP-IB address, and the other two are used to set the "MODE". On one setting the machine is configured only to talk (i.e. cannot accept commands over the bus). On the other setting the machine acts both as a listener and a talker. I have tried the ENTER command shown above in both modes (I even tried pressing the READ button), but so far the machine is mute.

Another thing that is strange with this clock is that the decimal dots of all the digits are always on. Does that mean something and how can I turn them off?

Any help really appreciated.

**vp

[Vassilis Prevelakis]

Oops, typo

I guess I cannot even write a one line program without making a mistake. The correct command is:

ENTER 717; A$

Since the 59309A should send a string terminated by a linefeed character.

**vp

[Andy]

You're in luck. I recently scanned the entire 59309a operating and service manual. I'll look up the commands tonight and post them.

I use a 59309a with my hp85. In the startup program, I call the time from the 59309a and use it to set the 85's clock. It works great.

I think the command is:

output 7??; "C"
input 7??;a

but like I said...I'll look it up tonight. There are also some dip switches inside the 59309a which set the format of data output.

Also, if you just got your 59309a, you should look inside and make sure noone installed an internal 9V backup battery since it could leak. I made a BNC-9V cable so I can utilize the 59309a's external 9V backup.

Its the perfect lab clock (except you need a magnifying glass to read it) 8^)

Andy