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Is there any way to recover if one messes up serial port on settings on HP GPS receivers?

DD
Dr. David Kirkby
Wed, Jun 17, 2020 11:55 AM

My HP 58503A is using the default 9600 8N1 for serial communication. It
would be nice to run the connection faster, and there are commands to
change the serial port speed, as well as reset the serial port settings to
the defaults. What concerns me is that if I try to run the serial port
faster, but have problems communicating with the receiver for whatever
reason, then there will be no way to reset the receiver - I could not run
the command to reset it. There's not an easily accessible "reset to factory
defaults" button on the receiver like there is on many devices. It seems
like one could get into a catch-22 situation, but perhaps there's a
solution I am unaware of.

Dave

My HP 58503A is using the default 9600 8N1 for serial communication. It would be nice to run the connection faster, and there are commands to change the serial port speed, as well as reset the serial port settings to the defaults. What concerns me is that if I try to run the serial port faster, but have problems communicating with the receiver for whatever reason, then there will be no way to reset the receiver - I could not run the command to reset it. There's not an easily accessible "reset to factory defaults" button on the receiver like there is on many devices. It seems like one could get into a catch-22 situation, but perhaps there's a solution I am unaware of. Dave
TV
Tom Van Baak
Wed, Jun 17, 2020 12:43 PM

Hi Dave,

My HP 58503A is using the default 9600 8N1 for serial communication. It
would be nice to run the connection faster

Sure, but running faster is usually a red flag. What is the actual
problem? Is it merely latency and timing or something else.

and there are commands to change the serial port speed,
as well as reset the serial port settings to the defaults.

Yes, from 1200 to 19200.

What concerns me is that if I try to run the serial port faster,
but have problems communicating with the receiver for whatever reason,

What do you mean by "problems", or "whatever reason"? The SCPI protocol
is well designed. You send a command and you wait for the response. As a
talker you stay synchronized with the responses. Are you writing your
own code? Post a sample.

then there will be no way to reset the receiver - I could not run the

command to reset it.

I'm not following. There is a reset at power up. You can also simulate a
reset with *rst. Under what conditions are you unable to send commands
to the receiver? Is it locked up? Did it crash? Are you using
flow-control? Is it your PC or the 58503 that's not responding?

There's not an easily accessible "reset to factory defaults" button

on the receiver like there is on many devices.

Pull the AC or DC power cord. I'm curious why you ask. What state is
your 58503A that you have to resort to this?

/tvb

Hi Dave, > My HP 58503A is using the default 9600 8N1 for serial communication. It > would be nice to run the connection faster Sure, but running faster is usually a red flag. What is the actual problem? Is it merely latency and timing or something else. > and there are commands to change the serial port speed, > as well as reset the serial port settings to the defaults. Yes, from 1200 to 19200. > What concerns me is that if I try to run the serial port faster, > but have problems communicating with the receiver for whatever reason, What do you mean by "problems", or "whatever reason"? The SCPI protocol is well designed. You send a command and you wait for the response. As a talker you stay synchronized with the responses. Are you writing your own code? Post a sample. > then there will be no way to reset the receiver - I could not run the command to reset it. I'm not following. There is a reset at power up. You can also simulate a reset with *rst. Under what conditions are you unable to send commands to the receiver? Is it locked up? Did it crash? Are you using flow-control? Is it your PC or the 58503 that's not responding? > There's not an easily accessible "reset to factory defaults" button on the receiver like there is on many devices. Pull the AC or DC power cord. I'm curious why you ask. What state is your 58503A that you have to resort to this? /tvb
DD
Dr. David Kirkby
Wed, Jun 17, 2020 3:49 PM

On Wed, 17 Jun 2020 at 13:45, Tom Van Baak tvb@leapsecond.com wrote:

Hi Dave,

There's not an easily accessible "reset to factory defaults" button

on the receiver like there is on many devices.

Pull the AC or DC power cord. I'm curious why you ask. What state is
your 58503A that you have to resort to this?

/tvb

Thank you Tom. I had assumed that the serial port settings would be
preserved in the event of a power failure.

As I reported a week or two ago, Lady Heather will not communicate well
with the receiver. I wondered if there was any point in trying a faster
serial port speed.

Lady Heather gets the time from the GPS receiver once, but then either

  1. Windows reports the program is not responding.

  2. The clock runs backwards.

I thought it might be worth trying different serial port settings.

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@kirkbymicrowave.co.uk
https://www.kirkbymicrowave.co.uk/
Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

On Wed, 17 Jun 2020 at 13:45, Tom Van Baak <tvb@leapsecond.com> wrote: > Hi Dave, > There's not an easily accessible "reset to factory defaults" button > on the receiver like there is on many devices. > > Pull the AC or DC power cord. I'm curious why you ask. What state is > your 58503A that you have to resort to this? > > /tvb Thank you Tom. I had assumed that the serial port settings would be preserved in the event of a power failure. As I reported a week or two ago, Lady Heather will not communicate well with the receiver. I wondered if there was any point in trying a faster serial port speed. Lady Heather gets the time from the GPS receiver once, but then either 1) Windows reports the program is not responding. 2) The clock runs backwards. I thought it might be worth trying different serial port settings. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom