New 2413S LED Actions?

[Brian H]

I have a question for anyone who may have a recent revision 2413S PLM.

 

I am trying to determine if the Red-Green Dual Color LED actions have changed.

 

Comparing a V1.0 Firmware v.92 with a V1.5 Firmware v.98.

Older one. LED is Dim Green. New one. LED is Bright Green.

Communications test:

Older one. Communicating on same phase. Flashing Red.

Newer one. Communicating on same phase. Flashing Red but every few seconds Bright Green.

 

I don't remember when I first started using the new one. That the LED was Bright Green and I am

wondering if something in the LED circuit may have failed.

The RF range also seems to have gotten shorter than I originally though it was.

[LeeG]

I see the same results between v92 and v98.

 

The v98 has always been a brighter green than the v92.

 

The green blink on the v98 happens at the 8/9/10th red blink (varies). Sometimes starts as a red blink and then switches to green, sometimes all green. At times I think it is just returning to the normal bright green rather than an explicit green blink.

 

Range on the v98 is less than the v92.

 

EDIT: an access point on the other end of the house in test mode is received by a v92 but not the v98 which is actually 2' closer to the source than the v92. Had to bring the access point being used for test to the middle of the house before both PLMs received the RF signal from the access point.

[Brian H]

Thank you for the tests and findings.

Looks like mine is normal for a v.98

If I look real CLOSE I can see the Green LED flicker on message handling. Unlike the v.92 that is more evident.

[ELA]

I got the same results also Brian,

 

My V1.5 hardware has a brighter green LED also.

 

I believe that there is an internal timer set at about 10 seconds.

When I was doing some testing a while back , sending "standard Broadcast phase A/B commands", I could see this "timeout" very pronounced.

If you sent the message a few times and then stopped, the LED would continue blinking until the internal timer- timed out.

 

It appears that the "green blip" is probably occurring at the timeout point. Might be confusing to some I think.

 

I could not recognize any difference in RF receive capability between my two units. They both worked at about 80ft away, both stopped in another location at about the same distance but at a different angle from the sender.

Too many variables in the home to judge that accurately (and too darn cold for an open field test).

[Brian H]

ELA, Thanks for the reports on how yours acted.

 

Yes RF can be strange. Learned that while I was a Two Way Radio Technician with Motorola.

[ELA]

Hi Brian, LeeG,

 

I had a little spare time this morning so I investigated the 4 tap comm test a little deeper. I wanted to be able to measure how often the access point was sending out an RF signal.

I had previously traced some circuitry on a PLM and today looked even deeper into the SI4420 transceiver chip used inside.

At pin 15 of this chip is an analog output that is RSSI (Received Signal Strength Indication).

I soldered a wire to this pin and brought it out of the case.

 

Seems to make a nice little signal strength meter. The output is only present for 35 msec , and the access point sends once every 1.0 seconds.

 

So you need a scope or circuit to measure the pulse amplitude.

I did a few quick measurements and got the following values:

 

distance between devices : Peak pulse amplitude

6" : 0.84Vp

4 ft : 0.7Vp

10ft : 0.58Vp

40ft : 0.34Vp

[Brian H]

Thank you for the tests and data.

Maybe time to get out a scope. Though all of mine not in use are v1.0-v1.6 Access Points and I believe they have a different chip on the RF Daughter Board.

[ELA]

I modified my Rev 1.5 (ver98) 2413U for this test.

 

It would be easy enough for me to feed this signal to the microcontroller on the ELAM to then present signal strength data to the display.

[Brian H]

OH. OK now I have a better understanding of what you did.

[ELA]

I found that my Fluke 87 can measure 1msec min/max and a fast enough meter could also work on this output.

There is a ~0.5vdc offset on the output and then the pulse rides on top of that.

[Brian H]

Thank you again for all the data you have accumulated.

I did discover my old v1.0-v1.6 Access Points also have the same transceiver chip in it.

I guess Silicon Labs also had a Integration division. One is an IA4420 and yours is a Si4420. Yet both have exactly the same data sheets.

 

I may take one of the v1.0R {refirb. from SignalLincRF swap offer} Access Points and mess around with it. To see if I can observe the signal you are pointing out. It has the older Linear Power Supply in it.