Temex LPFRS-01 analog frequency adjustement

[Mark Spencer]

Greetings.  I'm wondering if any one has any insight (or wishes to speculate) as
to how the external analog frequency adjustment on a Temex LPFRS-01 Rubidium
standard functions. 

 
From experimenting with one over the last few days there seems to be a step
function to the adjustment.   I'm wondering if frequency adjustment voltage is
read by an  ADC which is monitored by the CPU which adjusts the frequency ?  
(Or perhaps I'm just not adjusting the multi turn trimmer properly.)   

Regards
Mark Spencer
VE7AFZ

[Magnus Danielson]

Greetings. I'm wondering if any one has any insight (or wishes to speculate) as
to how the external analog frequency adjustment on a Temex LPFRS-01 Rubidium
standard functions.
From experimenting with one over the last few days there seems to be a step
function to the adjustment. I'm wondering if frequency adjustment voltage is
read by an ADC which is monitored by the CPU which adjusts the frequency ?
(Or perhaps I'm just not adjusting the multi turn trimmer properly.)

There is a CPU in there with ADC and DACs. You also have serial
interface to it, so you could hook it up to RS-232. Don't recall from
the top of my head if the levels is RS-232 or CMOS, but I can check...
as I have one.

Cheers,
Magnus

[Mark Spencer]

This post might be inappropriate. Click to display it.

[Magnus Danielson]

Thanks. I recall seeing documentation that more or less said that directly
connecting these units to an RS232 port will typically work but is not
guaranteed. If you are able to easily check your unit that would be great but I
will likely try connecting mine to an RS232 port in the next few weeks.

It's easy enough to access. But much easier is it to go to Spectratime
website and download the manual:
http://www.spectratime.com/products/isource/
http://www.spectratime.com/documents/lpfrs_manual.pdf

Already on page 1 I can read the label of the photo which says

6 : TXD (TTL)
9 : RXD (TTL)

Which is a good hint. Start reading at page 10 in the manual.

I wanted to get a sense of how well the unit is working prior to putting to much
effort into this. As it arrived with a circuit board that includes a frequency
adjust trimmer it was pretty simple to test.
The spec sheet indicates that the smallest frequency step for RS 232 control
is 1X10-11, and I was also curious if finer frequency control was possible via
the analog frequency adjust input. I suspect that 1 x 10-11 is the limit but
I'm not 100 percent sure of this.

See page 13 of the manual and you fill find your confirmation.

As for status, the serial interface should give you a bunch of status
report. I just haven't taken the time to hook it up.

Cheers,
Magnus

[Mark Spencer]

Thanks

The doccumentation regardings RS232 controll looks usefull.   (I had not seen
this before, and in case any one else is following this thread here is a link..)
http://www.spectratime.com/documents/lpfrs_rs_232.pdf


Regards
Mark S

 


----- Original Message ----
From: Magnus Danielson <magnus-0aYeopylZ8Qi5CQI31g/s0B+***@public.gmane.org>
To: time-nuts-***@public.gmane.org
Sent: Mon, March 7, 2011 11:10:13 AM
Subject: Re: [time-nuts] Temex LPFRS-01 analog frequency adjustement

Thanks.  I recall seeing documentation that more or less said that directly
connecting these units to an RS232 port will typically work but is not
guaranteed.  If you are able to easily check your unit that would be great but
I
will likely try connecting mine to an RS232 port in the next few weeks.

It's easy enough to access. But much easier is it to go to Spectratime website
and download the manual:
http://www.spectratime.com/products/isource/
http://www.spectratime.com/documents/lpfrs_manual.pdf

Already on page 1 I can read the label of the photo which says

6 : TXD (TTL)
9 : RXD (TTL)

Which is a good hint. Start reading at page 10 in the manual.

I wanted to get a sense of how well the unit is working prior to putting to much
effort into this.  As it arrived with a circuit board that includes a

frequency

adjust trimmer it was pretty simple to test.
  The spec sheet indicates that the smallest frequency step for  RS 232 control
is 1X10-11, and I was also curious if finer frequency control was possible via
the analog frequency adjust input.  I suspect that 1 x 10-11 is the limit but
I'm not 100 percent sure of this.

See page 13 of the manual and you fill find your confirmation.

As for status, the serial interface should give you a bunch of status report. I
just haven't taken the time to hook it up.

Cheers,
Magnus

_______________________________________________
time-nuts mailing list -- time-nuts-***@public.gmane.org
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

[Arthur Dent]

“Greetings. I'm wondering if any one has any insight (or wishes to speculate)
As to how the external analog frequency adjustment on a Temex LPFRS-01
Rubidium standard functions.”
++++++++++++++++++++++

The spec sheet says 0-5 volts for analog adjustment. The unit supplies a 5V
hi-stability reference voltage to feed the pot you are using. An external
10kΩ variable resistor wired between the 5V reference supply and ground with
the wiper connected to the frequency adjust pin can provide this adjustment.

-Arthur



_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailm