Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
If you use the offset command, you can correct this bias but it will be at the cost of moving your hardware 1pps output off an equivalent amount in the opposite direction. Greg, that's understandable. I don't use the PPS output from these boxes so that isn't really a concern for me. Besides being a NTP server for my little network I use the IRIG signal to feed to an old NTS-100, which in turn converts UTC time to local 12 hr time for my IRIG clocks. Even though the NTS-100 is very old (you have to set version 3 explicitly if you want modern NTP to recognize it), it's very customizable in relation to daylight savings start/end and 12/24 hr display. :) If the TS-2100's were my only time servers, I probably wouldn't even mess with it because the time is so close, certainly better than what could be achieved syncing over the Internet. I think an offset of -4000 on the ts2100 seems to be pretty close to my other time servers. remote refid st t when poll reach delay offset jitter == *NET4501-1 .GPS. 1 u 22 64 3770.7440.027 0.099 +NET4501-2 .GPS. 1 u 66 64 3770.825 -0.009 0.107 +PRAECIS .GPS. 1 u7 64 3770.7610.043 0.061 +TS2100-1.GPS. 1 u 26 64 3775.0390.023 0.034 +TS2100-2.GPS. 1 u 50 64 3775.142 -0.015 0.037 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
Greg, I guess I had to wait until my coffee kicked in this morning before it clicked that it was in nanoseconds... I'm trying -3000 to see where that gets me, it seems to be nudging the time more in-line with my other NTP servers. As others have asked, how do we get this value to be persistent across reboots? Is there a way to write it to the eeprom or nvram or whatever? Is there any documentation on all the various commands in the eng/ directory? I want to tinker but I don't want to break my unit! Thanks as always, Jason ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
I'll try to take a look and see if there is a way to set an arbitrary value that is stored across boot cycles. I would have thought it would work that way already but if it's not, I'll have to check. And you are correct that any offset you program into the offset field should show up if you compare a baseline GPS pps against the output 1pps from the device. I would caution against using the lock light if you are playing with different control values. The lock light is a simple aggregation indicator of signal source available + phase offset x microseconds + phase offset / time x nanoseconds / second. I think the values of x and y were set based on reference source but there isn't much in the way of hysteresis and I've occasionally had tests where I tweaked variables which resulted in large overshoot and the lock light toggling for a while. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Robert Watzlavick.com Sent: Thursday, March 31, 2011 9:58 AM To: Discussion of precise time and frequency measurement Cc: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO Thanks-that explains it. But I can't make an arbitrary offset value stick across a power cycle. Is that what the info field does? I was trying to compare the 1 PPS from my ts2100 to the Thunderbolt but my HP 5316 only has 100 ns resolution. I would think the offset should show up as a skew on the PPS output. -Bob On Mar 31, 2011, at 11:44 AM, Greg Dowd gd...@symmetricom.com wrote: The offset command in the TS2100 is just a phase stepper in 100ns steps. Usage was originally targeted at compensating for the GPS antenna cable length (~ns/ft). As it turned out, we used it for another purpose as well. The very first models of the 2100 used an external GPS receiver (Trimble Acutime) which had an open collector 1PPS. Because of that, we triggered the phase capture on the falling edge of the input signal. When we migrated the design to support an internal receiver (CM3 IIRC), somebody forgot that and we didn't have an extra inverter available at the right spot. What I ended up doing was some conniptions inside the box where we would still trigger on the falling edge and I would use the different default values of offset as compensation for the pulse width. Unfortunately, as we changed GPS modules (CM3-Ace-AceII), the pulse width changed and I don't think anyone ever went back and fixed it. So, between all the different models, and due to the availa bility of add-on GPS conversion kits, many of these units ended up with different values of info which corresponded to difference GPS receivers and some phase offsets. I'd say just set it to whatever works. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Robert Watzlavick Sent: Thursday, March 31, 2011 6:24 AM To: Discussion of precise time and frequency measurement Cc: Jason Rabel Subject: Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO I changed the root/eng/timing/offset parameter from -100 to 0 on my unit and let it sit overnight. This morning, it is locked and without a frequency offset. So I wonder why my unit would have had a 100 ns offset programmed into it? I cannot figure out how to get the 0 value to stick though. When I power cycle it, it returns back to -100. I programmed various values into to the info field, restarted the unit, and read the following results for the offset parameter: 0x -5 0x0010 -5 0x0021 -5 0x0022 -5 0x0024 -100 0x0028 -5 This is interesting for a couple of reasons. First, it matches what Jason is seeing in his units with the -5 ns value for offset. However, a different TS2100-IRIG unit I looked had an info value of 0 and its offset was also 0. Maybe the presence of the GPS unit makes it think it needs an extra offset? We know that bit 6 is used for GPS vs. UTC for the NTP time (from the manual). I suspect bits 2 and 5 are for GPS since my unit was delivered that way. I would think at least 2 bits would be for the osc type but which ones? And if Jason's unit came delivered as an OCXO, why aren't any bits set to signify that? Maybe the TCXO/OCXO is one configuration and the Rubidium is another. It someone had a factory configured Rubidium unit, it would be interesting to know if there are any bits that correspond to it. -Bob On 03/30/2011 08:40 PM, Robert Watzlavick wrote: My unit (TCXO/GPS originally) has the root/eng/timing/offset set to -100. A TCXO-IRIG unit that I looked at has an offset value of 0. When I was first bringing up my unit with the OCXO, I was comparing the 10 MHz output against a stabilized Thunderbolt and I noticed the TS2100 EFC voltage seemed to stabilize
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
Well the units are 100ns each so if you set offset to 3, it should shift the 1pps output by 300ns. Another point is that there is significant asymmetry in the ntp packet processing if you are looking at accuracy. For the 1996 time of day requirement of 100ms, it was moot. If you set the box up in GPS mode and look at the 1pps output from the box, and set the offset so that the 1pps is within 1 usec of a known UTC reference, you will see that the transmit timestamps on ntp replies are a few ms late due to the tx latency in the device. The rx timestamps errors are more interrupt latency (10-100 microseconds). The net result is that your network clients will see a bias in the TS2100 clock (bias = rt/2). If you use the offset command, you can correct this bias but it will be at the cost of moving your hardware 1pps output off an equivalent amount in the opposite direction. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Jason Rabel Sent: Friday, April 01, 2011 10:21 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO Greg, I guess I had to wait until my coffee kicked in this morning before it clicked that it was in nanoseconds... I'm trying -3000 to see where that gets me, it seems to be nudging the time more in-line with my other NTP servers. As others have asked, how do we get this value to be persistent across reboots? Is there a way to write it to the eeprom or nvram or whatever? Is there any documentation on all the various commands in the eng/ directory? I want to tinker but I don't want to break my unit! Thanks as always, Jason ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
The offset command in the TS2100 is just a phase stepper in 100ns steps. Usage was originally targeted at compensating for the GPS antenna cable length (~ns/ft). As it turned out, we used it for another purpose as well. The very first models of the 2100 used an external GPS receiver (Trimble Acutime) which had an open collector 1PPS. Because of that, we triggered the phase capture on the falling edge of the input signal. When we migrated the design to support an internal receiver (CM3 IIRC), somebody forgot that and we didn't have an extra inverter available at the right spot. What I ended up doing was some conniptions inside the box where we would still trigger on the falling edge and I would use the different default values of offset as compensation for the pulse width. Unfortunately, as we changed GPS modules (CM3-Ace-AceII), the pulse width changed and I don't think anyone ever went back and fixed it. So, between all the different models, and due to the availability of add-on GPS conversion kits, many of these units ended up with different values of info which corresponded to difference GPS receivers and some phase offsets. I'd say just set it to whatever works. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Robert Watzlavick Sent: Thursday, March 31, 2011 6:24 AM To: Discussion of precise time and frequency measurement Cc: Jason Rabel Subject: Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO I changed the root/eng/timing/offset parameter from -100 to 0 on my unit and let it sit overnight. This morning, it is locked and without a frequency offset. So I wonder why my unit would have had a 100 ns offset programmed into it? I cannot figure out how to get the 0 value to stick though. When I power cycle it, it returns back to -100. I programmed various values into to the info field, restarted the unit, and read the following results for the offset parameter: 0x -5 0x0010 -5 0x0021 -5 0x0022 -5 0x0024 -100 0x0028 -5 This is interesting for a couple of reasons. First, it matches what Jason is seeing in his units with the -5 ns value for offset. However, a different TS2100-IRIG unit I looked had an info value of 0 and its offset was also 0. Maybe the presence of the GPS unit makes it think it needs an extra offset? We know that bit 6 is used for GPS vs. UTC for the NTP time (from the manual). I suspect bits 2 and 5 are for GPS since my unit was delivered that way. I would think at least 2 bits would be for the osc type but which ones? And if Jason's unit came delivered as an OCXO, why aren't any bits set to signify that? Maybe the TCXO/OCXO is one configuration and the Rubidium is another. It someone had a factory configured Rubidium unit, it would be interesting to know if there are any bits that correspond to it. -Bob On 03/30/2011 08:40 PM, Robert Watzlavick wrote: My unit (TCXO/GPS originally) has the root/eng/timing/offset set to -100. A TCXO-IRIG unit that I looked at has an offset value of 0. When I was first bringing up my unit with the OCXO, I was comparing the 10 MHz output against a stabilized Thunderbolt and I noticed the TS2100 EFC voltage seemed to stabilize but there was an offset in the 10 MHz output. The lock LED wasn't turning on either. I got impatient and started poking around and that's when I noticed the offset parameter was set to -100. I changed it to 0 and the lock LED immediately turned on but then the EFC started heading the other direction. I put it back at -100, let it sit for a few hours, and it eventually locked without a frequency offset. I'll set my offset back to 0 and see where it ends up overnight. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
To all: I ran the root eng ee info on my two TS2100s, both were originally IRIG units but I upgraded them myself to GPS models... Both my OCXO unit and TCXO unit reported As for the parameters in my timing / utils directory, here's both models: OCXO (MTI 240-0530-D) - gain = -20 filter = 0.9995000 low = 0.000 (Manual says this isn't used, but figured I would post it) d/a = 0xa05d tfp 0 = 0xa005 tfp 6 7 = 0.9994965 TCXO --- gain = 2 filter = 0.950 low = 0.000 d/a = 0x85c0 tfp 0 = 0x85a4 tfp 6 7 = 0.9499970 My OCXO model came from Yahoo!, it still has the asset sticker on the side. It was in free-run mode when I got it. As mentioned above, the OCXO is a MTI with the following info: Model: 240-0530-D PN: 010285-0530 If you want to see some hi-res images: http://www.rabel.org/archives/Images/TS2100/ Time to poke around the eng directory and see if I can fix that pesky offset compared to my other time servers... There used to be a command in the earlier firmware versions but it appears they removed it. remote refid st t when poll reach delay offset jitter +NET4501-1 .GPS. 1 u 37 64 170.714 -0.029 0.087 *NET4501-2 .GPS. 1 u- 64 770.820 -0.022 0.129 +PRAECIS.GPS. 1 u 61 64 370.7120.052 0.058 -TS2100-1 .GPS. 1 u 63 64 374.937 -0.406 0.025 -TS2100-2 .GPS. 1 u- 64 774.976 -0.366 0.046 The root / eng / timing / offset shows: Current offset : -5 at offset unit (100ns) I wonder if that might do the trick? Hmmm... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
There are some hidden configuration parameters in the TS2100 that vary by oscillator type (between TCXO,OCXO, and Rb), and include some control loop parameters. It matters a lot that the firmware uses the correct algorithm and parameters. The Rubidiums are quite far from the crystals, but I assume that there is a smaller difference between crystal types. Joe From: Robert Watzlavick roc...@watzlavick.com To: time-nuts@febo.com Date: 03/25/2011 12:39 AM Subject: [time-nuts] Upgrading TS2100 from TCXO to OCXO Sent by: time-nuts-boun...@febo.com I've been able to successfully upgrade my Datum TS2100 to an OCXO from the stock TCXO. I didn't see it in the archives so I thought I'd post my findings. I noticed that the same firmware was used regardless of oscillator configuration so there must either be jumpers or a hidden set of commands. The newer versions of the ET6000 have jumpers to select the oscillator but I couldn't find anything similar on the TS2100. However, in the back of the manual, 8500-0033 Rev K, Appendix I describes how to reconfigure the unit to output GPS instead of UTC for NTP. I'm not interested in that but there are some hints about a hidden menu structure (root eng ee) which allows you to change EEPROM settings. Here's the hidden menu items: root eng: start net interface timing tools / serial tools / eeprom tools / spi tools / flash tools / display tools / memory tools / intrinsic help Going further into one of them, root eng eeprom: ethernet address board serial number gain default filter constant low filter constant precision set eeprom get eeprom read serial eeprom write serial eeprom tx 16 bits to eeprom location for image info value eeprom_select intrinsic help So that's where the default gain and filter constants are set. You have to jumper across J4 on the PC board to allow EEPROM writes or you get an error. Not sure what the precision setting is for (it's currently -19). I don't have the proper OCXO (yet) but I do have an MV89A OCXO that I was able to wire into the circuit temporarily. There is 12V on the board and the 0.5-4.5V EFC range works well with the MV89A. I used a gain of +20 and a filter setting of 0.9994965 based on Jason Rabel's post from 9/26/2010 (note the sign change on the gain). The EFC algorithm had a pretty good overshoot during the first adjustment cycle and took over an hour to completely settle in but eventually the front panel Locked LED turned on. I couldn't find a way to change the starting value for EFC (d/a) value. I *think* an Abracon AOCJY1A-10.000MHz-E-SW part will be pin compatible on the board. Unfortunately nobody has that one in stock and it's a 10 week lead time so I may end up installing one off-board. The MV89A is too tall to fit with the lid on so it's not a long term option. I traced out the two SMA pads on the board and they are for the EFC out and RF in so I could always run them to the back of the unit and put the OCXO outside the unit. -Bob K5RLW ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
I think a couple of those bits do correspond to the oscillator type installed but I think you can ignore them. If I remember right, those oscillator bits were only used to calculate the dispersion update for ntp packets when flywheeling through a loss of signal. As far as I recall, you just need to change gain and filter. And the setting for the current d/a value should have been accessible in root tim utils as d2a. As someone pointed out, the default ovenized for those boxes was the MTI 240 low profile. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Robert Watzlavick Sent: Sunday, March 27, 2011 3:54 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO If anybody has a TS2100 that came from the factory with an OCXO, can you telnet into the unit and run the following command? root eng ee info This appears to be some sort of factory-configured personality of the board. My TS2100-GPS unit with a TCXO has an info value of 0024. A TS2100-IRIG unit (no GPS) with a TCXO has a value of . I'm curious whether any of those bits correspond to the oscillator type or if all that needs to be changed is the gain. Thanks, -Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
I have MTI 240s if you need one. Greg On 3/28/2011 6:28 PM, Greg Dowd wrote: I think a couple of those bits do correspond to the oscillator type installed but I think you can ignore them. If I remember right, those oscillator bits were only used to calculate the dispersion update for ntp packets when flywheeling through a loss of signal. As far as I recall, you just need to change gain and filter. And the setting for the current d/a value should have been accessible in root tim utils as d2a. As someone pointed out, the default ovenized for those boxes was the MTI 240 low profile. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Robert Watzlavick Sent: Sunday, March 27, 2011 3:54 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO If anybody has a TS2100 that came from the factory with an OCXO, can you telnet into the unit and run the following command? root eng ee info This appears to be some sort of factory-configured personality of the board. My TS2100-GPS unit with a TCXO has an info value of 0024. A TS2100-IRIG unit (no GPS) with a TCXO has a value of . I'm curious whether any of those bits correspond to the oscillator type or if all that needs to be changed is the gain. Thanks, -Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
That's good to know. I've been running the TS2100 for a few days with a Morian MV89A (too big to fit into the case though) and it seems to work well, definitely more stable than the TCXO. A test that I haven't run yet is to pull the GPS antenna and see how long the NTP server reports Stratum 1 performance and what the dispersion values are. You're correct about the d/a setting - it seems all you have to is set it and it stores it in NVRAM. -Bob On 03/28/2011 07:28 PM, Greg Dowd wrote: I think a couple of those bits do correspond to the oscillator type installed but I think you can ignore them. If I remember right, those oscillator bits were only used to calculate the dispersion update for ntp packets when flywheeling through a loss of signal. As far as I recall, you just need to change gain and filter. And the setting for the current d/a value should have been accessible in root tim utils as d2a. As someone pointed out, the default ovenized for those boxes was the MTI 240 low profile. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Robert Watzlavick Sent: Sunday, March 27, 2011 3:54 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO If anybody has a TS2100 that came from the factory with an OCXO, can you telnet into the unit and run the following command? root eng ee info This appears to be some sort of factory-configured personality of the board. My TS2100-GPS unit with a TCXO has an info value of 0024. A TS2100-IRIG unit (no GPS) with a TCXO has a value of . I'm curious whether any of those bits correspond to the oscillator type or if all that needs to be changed is the gain. Thanks, -Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
If anybody has a TS2100 that came from the factory with an OCXO, can you telnet into the unit and run the following command? root eng ee info This appears to be some sort of factory-configured personality of the board. My TS2100-GPS unit with a TCXO has an info value of 0024. A TS2100-IRIG unit (no GPS) with a TCXO has a value of . I'm curious whether any of those bits correspond to the oscillator type or if all that needs to be changed is the gain. Thanks, -Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
Not sure what the precision setting is for (it's currently -19). That's probably for NTP. Roughly, it's how many useful bits of data you get when you read the clock. I can probably find a description if anybody is curious. -19 is 2 microseconds which is a reasonable ballpark for an embedded system. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
Ok, thanks. I was so focused on the IRIG and 10 MHz parts I didn't think about the NTP function (which is what the unit is for after all). BTW - I had some misinformation in my original post. The Abracon AOCJY1A is probably pin compatible with the TS2100 but it's not voltage compatible. The OCXO supply voltage on PC board pads is 12 not 5 volts. So unless I can get the same MTI 240 OCXO, then I'm looking at just putting one in the case somewhere and running wires to it. I'd prefer not to cut traces. Anybody know of an inexpensive OCXO that meets the following criteria? 10 MHz sine output 12V or 5V supply voltage (either will work since it will be installed off board) 5V EFC (TS2100 DAC is 0.5-4.5V) Small enough to fit in a 1U rack enclosure (the Morion MV89A is too tall) I'm not striving for perfection, just some that is significantly better than the stock TCXO. -Bob On 03/25/2011 02:11 AM, Hal Murray wrote: Not sure what the precision setting is for (it's currently -19). That's probably for NTP. Roughly, it's how many useful bits of data you get when you read the clock. I can probably find a description if anybody is curious. -19 is 2 microseconds which is a reasonable ballpark for an embedded system. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO
I have MTI 240 OCXOs Greg On 3/25/2011 10:02 PM, Robert Watzlavick wrote: Ok, thanks. I was so focused on the IRIG and 10 MHz parts I didn't think about the NTP function (which is what the unit is for after all). BTW - I had some misinformation in my original post. The Abracon AOCJY1A is probably pin compatible with the TS2100 but it's not voltage compatible. The OCXO supply voltage on PC board pads is 12 not 5 volts. So unless I can get the same MTI 240 OCXO, then I'm looking at just putting one in the case somewhere and running wires to it. I'd prefer not to cut traces. Anybody know of an inexpensive OCXO that meets the following criteria? 10 MHz sine output 12V or 5V supply voltage (either will work since it will be installed off board) 5V EFC (TS2100 DAC is 0.5-4.5V) Small enough to fit in a 1U rack enclosure (the Morion MV89A is too tall) I'm not striving for perfection, just some that is significantly better than the stock TCXO. -Bob On 03/25/2011 02:11 AM, Hal Murray wrote: Not sure what the precision setting is for (it's currently -19). That's probably for NTP. Roughly, it's how many useful bits of data you get when you read the clock. I can probably find a description if anybody is curious. -19 is 2 microseconds which is a reasonable ballpark for an embedded system. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Upgrading TS2100 from TCXO to OCXO
I've been able to successfully upgrade my Datum TS2100 to an OCXO from the stock TCXO. I didn't see it in the archives so I thought I'd post my findings. I noticed that the same firmware was used regardless of oscillator configuration so there must either be jumpers or a hidden set of commands. The newer versions of the ET6000 have jumpers to select the oscillator but I couldn't find anything similar on the TS2100. However, in the back of the manual, 8500-0033 Rev K, Appendix I describes how to reconfigure the unit to output GPS instead of UTC for NTP. I'm not interested in that but there are some hints about a hidden menu structure (root eng ee) which allows you to change EEPROM settings. Here's the hidden menu items: root eng: start net interface timing tools / serial tools / eeprom tools / spi tools / flash tools / display tools / memory tools / intrinsic help Going further into one of them, root eng eeprom: ethernet address board serial number gain default filter constant low filter constant precision set eeprom get eeprom read serial eeprom write serial eeprom tx 16 bits to eeprom location for image info value eeprom_select intrinsic help So that's where the default gain and filter constants are set. You have to jumper across J4 on the PC board to allow EEPROM writes or you get an error. Not sure what the precision setting is for (it's currently -19). I don't have the proper OCXO (yet) but I do have an MV89A OCXO that I was able to wire into the circuit temporarily. There is 12V on the board and the 0.5-4.5V EFC range works well with the MV89A. I used a gain of +20 and a filter setting of 0.9994965 based on Jason Rabel's post from 9/26/2010 (note the sign change on the gain). The EFC algorithm had a pretty good overshoot during the first adjustment cycle and took over an hour to completely settle in but eventually the front panel Locked LED turned on. I couldn't find a way to change the starting value for EFC (d/a) value. I *think* an Abracon AOCJY1A-10.000MHz-E-SW part will be pin compatible on the board. Unfortunately nobody has that one in stock and it's a 10 week lead time so I may end up installing one off-board. The MV89A is too tall to fit with the lid on so it's not a long term option. I traced out the two SMA pads on the board and they are for the EFC out and RF in so I could always run them to the back of the unit and put the OCXO outside the unit. -Bob K5RLW ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
