NDAQ Serial / Analog Interface Panel Layout:

This document is a combination of notes taken related to interfacing the Maxstream Radios to the Campbell CR10X loggers as well as Operations Notes relevant to TREX-06. Some of the contents are informational only and will not apply for operational considerations.

For TREX-06, the radiometer stands are connected via a wireless (Maxstream) link to the NDAQ at each of the 3 tower installations. A solar panel / charger inside the logger boxes provide power for the logger, radio and sensors. The NIDS have a separate gray ‘radio box’ that connects via a standard Bulgin cable assembly. These boxes include a switch and LED indicating when power is applied. They are configured to remain powered up full time (ie no pin/port-sleep) so that they receive data continuously from the loggers. The logger radios are configured for ‘port-sleep’ in the case of the 9Xtend and Xstream radios. Each of the tower sites will have different Maxstream radios (due to inventory limits): Central has XBee radios which ultimately will have Zigbee firmware installed in the future, but not presently. The West/South have a pair of 9Xtend and Xstream radios respectively (I believe). The maxstream radios are interfaced to the loggers using standard RS232 communications via Campbell’s SC32A converter module attached to the ‘Radio Modem’ version of the Maxstreams. Comments below concerning the ‘+5 Volt’ interfacing do not apply.

Operational Considerations:

1) Maxstream Setup Program: ‘X-CTU’

This is a Windows XP program that lives on both the Panasonic Toughbook and Bison Latitude PC. On the bench you need to connect a power supply and a straight DE-9 serial cable to the maxstream radio. These can be found in the ‘spares’ box. At the station you need to use the ‘DE9 to Bulgin’ cable to the logger box and do two things: disconnect the CR10X logger (best to just unplug it’s power), and move the toggle switch next to the radio to the ‘radio’ position. This allows the console port to talk to the radio instead of to the CR10X. Don’t forget to put the switch back and power to the CR10X when you’re done interacting with the radio.

2) Talking to the CR10X Remotely

It is possible to start a ‘minicom’ or ‘rserial’ session through the NIDS to the CR10X to look at its program and/or calibration table. If needed it is probably better to do this directly rather than via the wireless link because of the ‘sleep’ considerations’ of the radios. It is possible to lock up the CR10X via the wireless method although I did confirm that the logger will automatically restart ‘eventually.’ What happens is if you don’t type commands fast enough, the radio will not get any activity on it’s receive line and will decide to go to sleep; meanwhile the logger is waiting for more commands from you.

3) Battery Power

The solar panels are fairly closely matched to the expected load. Since the battery voltage is reported by the loggers, it is recommended to monitor how the solar charging system vs load is performing.

4) RF Power / Range / Antennas

To save power the 9Xtends have been set to 10mW-RF which is the lowest of the sets. The XBee’s are at 60mW (I recall) and the Xstreams are set at 100mW-RF. This should be adequate for ranges up to 300-feet without any difficulty assuming the antennas are visible to each other. Note the position of the antennas during setup and try to keep them on the same side of the boxes/towers.

Logger / Radio Power Measurements:

Measured Loads at 12.5VDC:

.25W 20mA Logger running simulated code

.29W 23mA Logger/232 running simulated code

.35W 27mA QuasiEstimated level with sensors (paritally

measured with 1pyg,1psp,1tsoil,1tp01)

.80W ~60mA Logger/232 + Radio Modem (10mW-RF,port-sleep 'D'*100mS)

1.2W 90mA Logger/232 + Radio Modem (100mW-RF), port-sleep

OEM Radio Option, 5V See notes about how to interface the OEM module directly.

.15W 30mA OEM Radio alone (10mW-RF), using CR10X +5

.45W 90mA ditto, except with full-time receive enabled

.53W 105mA ditto, with inverting hex buffer (pick another!)

0.5mA pin shutdown of OEM

Estimated

.50W OEM estimated with 1.5 sec. receive on, then sleep

.88W OEM on full time receive.

9Xtend modem: measured	12.5V at	10mW-RF	100mW-RF	1W-RF
	9600bps RF	105mA	160mA
	115kbps RF	88mA	115mA	220mA
	Receive	73mA
9Xtend OEM : specification	5V at	140mA	270mA	730mA
XBee	12.5	240mA
Xstream	12.5 – Rcv	74mA
	12.5 – Xmit	140mA
CR10 w/ port sleep 0x14	Avg	63mA

A nominal 7AH battery has been placed in the logger boxes and a 5-10W solar panel should be placed flat on top of the box/stand where it will not be seen by the radiometers. Panel sizes are not much larger than the logger box itself.

If the average power consumption remains below 1W, small panels presuming roughly 4W output during 5 sun-hours should maintain the battery. From measurements above it appears the load may remain under .8W total average power for 5-sec. messages. For safety if we assume a 1-1.5W load the 10W panels would be better, at the 'expense' of size.

Inventory of Radios:

2 Maxstream 9XTend modems (high-power units)

4 Maxstream Xstream (19.2) modems (1 set = spare)

6 XBEE (1 = spare)

Interfacing CR10X - Maxstream:

NOTE of Interest: Campbell already sells a maxstream product to their loggers: RF400 and RF401 for ~$400. These are specially built maxstream products limited to 100mW-RF using 75mA-xmit / 25mA-rcv; and 9600bps (i believe).

Interfacing the Maxstream RF modem to the 10X / SC23A RS232 module is trivial. Power for the modem is available using the +12 taps on the logger. The disadvantage is the added power used for converting to RS232 levels and the +12 supply.

Interfacing directly to the CR10X DE-9 I/O port: the 5-Volt Option.

Interfacing a Maxstream OEM module directly to the 10X is more involved. Power savings would be roughly .3W at 10mW-RF. There are 3 issues: +5V supply, handshaking and protocol. The +5 on the logger de9 can handle the OEM at 10mW-RF (200mA supply for specified 150mA load max), however cannot run the radio at higher RF levels. For short distances the 10mW-RF should be adequate.

The logger uses handshaking but this should be easily addressed. The CR10X sets pin-3 (RI) high indicating it wants to initiate communications and the modem should set pin-5 (ME) indicating it is ready to receive. The opposite procedure is needed for the radio to initiate incoming comms; ie analagous to typical hardware RTS/CTS. During prelim. test, the radio was set to disable handshaking and the result was incoming communications did not function although outgoing messages did flow. A bit more problematic, the logger uses inverted logic signals. During prelim. test this resulted in 'garbage' characters being received.

To run the 10X to OEM radio a separate interface is needed. This would provide +5 for the EOM via the logger 12V supply, allowing higher RF power levels, and would incorporate an inverting buffer to translate characters back to normal logic. Handshaking should be accomplished via maxstream setup. For the XBee OEM, the same is true except using 3.3V logic.

Setup of the Maxstream:

To save power I set the 9Xtend and Xstream maxstreams to use its port-sleep function which turns off the radio if nothing is received at the Rx for a certain period. If this time is set too quickly, then talking to the CR10X can become problematic because if you type too slowly the logger will not reply within this period and will appear to lock up. Using setting of 'D' (~2-sec) appeared to be the best compromise to save power and still worked for normal interaction with the logger. If we never need to communicate back to the logger this value can be set lower and there are some other 'pin-sleep' options that may be better as well. The pin-sleep option could be incorporated into an OEM interface module. The XBee doesn't have port-sleep so we would need to use the cyclic sleep or pin-sleep to save power.

Notes & brief Comparison of Maxstream 9Xtend / XBee

XBee will have true mesh networking software: due 1stQ.06 (maybe jan-06)

Xtend has some beta software coming that is a quasi repeater function, using the source/destination address. Any radio in the network mask that hears a broadcast that is not for it, will rebroadcast it until it reaches the dest. Any radio having done a rebroadcast, will ignore echoes of the same query, but will wait to receive the 'reply-string' coming back and resend that. ie probably 25% efficiency loss in small network, 90% in large.

XBee 250kbps RF rate

Zigbee mesh networking

2.4MHz band (has some ability to occupy alternate freqs in presence of wifi)

.06,.1W RF output (1-mile outdoors, 100m indoors)

3.3V operation and cmos i/o

no sio port sleep option, but has pin&cyclic sleep + pin shutdown

9Xtend 115kbps / 9600 RF rate

quasi-repeater rebroadcast source-destination addressing.

900MHz band

.001-1W RF output (up to 20Miles@115k, 40@9600)

2.8-5V operation

sio-port sleep option + pin/cyclic sleep + pin shutdown

Wiring for 5V Option: CR10X – 9Xtend OEM direct:

CR10X DE-9			9Xtend 2x10 header
Desc.	Pin		Pin	Desc.
+5V at 200mA	1		2	Vcc (2.8-5.5)
Gnd	2		1	Gnd
RI	3		10 (optional RTS)	GPIn1, RTS, Command Port
Rx, (5V level input)	4	Invert Reqd	6	DO data out
ME modem enable	5		9 (optional CTS)	GPOut1, CTS, RX485 tx-enable
PE sync.dev. enable for buss ops	6
Clock / handshake	7
+12V	8
Tx, (5V level output)	9	Invert Reqd	5	DI data in
			7 (+5 or cr10 dio)	Pin shutdown, active low
			8 (optional pin-sleep)	GPIn2, Pin Sleep
			11	Config (pwr-up), RSSI-pwm
			12-20	Reserved

Wiring for RF Modem Option: CR10X SC23A – 9Xtend, Xstream or XBee modems:

CR10X SC23A DB-25			RF Modem DE-9 (male)
Desc.	Pin		Pin	Desc.
+5V at 200mA	1			Vcc (2.8-5.5)
Gnd	7		5	Gnd
Rx, (To …)	2	Invert Reqd	6	DO data out
+12V	8
Tx, (To …)	9	Invert Reqd	5	DI data in

Wiring for RF Modem Option: NDAQ – 9XTend, Xstream or XBee modems:

NDAQ Bulgin		RF Modem DE-9 (male)
Desc.	Pin	Pin	Desc.
+12	1	9	Optional Power, Vcc (2.8-5.5)
CTS	3	8 (optional CTS)	Optional flow ctrl not needed or used
RTS	4	7 (optional RTS)	Optional flow ctrl not needed or used for optional binary commands
Rx (to NDAQ)	5	2
Tx (to modem)	6	3
DTR	7	4 (DO NOT CONNECT)	Optional Shutdown pin. Can only be used w/ViperCom1/4
Gnd	8	5

For Xbee RF Modems: Setup

Maxstream Pin-Sleep Function:

Maxstream requirements:

9Xtend:

Hardware sleep is available on the OEM module but not the RF modem: <1microA

Pin-Sleep, SM=1 is available on the RF Modem: DTR DE-9 pin-4, <17mA, off= logic high

Port-Sleep, SM=2, serial port sleep after ST=x*mS of inactivity, easy-probably best to use.

XStream:

Pin-Sleep, SM=1 is available on the RF Modem: DTR DE-9 pin-4, <6mA, off= logic high

Port-Sleep, SM=2, serial port sleep after ST=x*mS of inactivity, easy-probably best to use.

XBee:

Hardware sleep is available on the OEM module but not the RF modem: <10microA

Pin-Sleep, is available on the RF Modem: <25mA,

SM=1 is for pin-hibernate that takes least power and wakes up in 13.5mS

SM=2 is for pin-doze that takes more power but wakes up in 2mS

Logic Level: DTR DE-9 pin-4=high=awake, DTR=low=sleep (opposite others)

Port-Sleep, not available.

CR10 Logger code to toggle pin-sleep:

Add this command at the beginning of the main program table just as it starts execution:

; go to turn on the maxstream line
1: Do (P86)
1: 7        Call Subroutine 7

Subroutine 7 looks like this:
----------------------------
; Let's use subroutine 7 for delaying for the maxstream radio to turn-on
16: Beginning of Subroutine (P85)
1: 7        Subroutine 7

17: Do (P86)
1: 43       Set Port 3 High      ; this turns on port C3 to +VDC

18: Beginning of Loop (P87)
1: 0000     Delay
2: 2000     Loop Count

19: Do (P86)
1: 17       Set Flag 7 High

20: Do (P86)
1: 27       Set Flag 7 Low

21: End (P95)

22: End (P95)

---------------------------
with these simple toggles of the flags (which i couldn't see you using anywhere) the loop count of 2000 is very close to 2-seconds.   i tried this all the way up to 9999~=10 seconds.   then within your 5-second processing loop the first 2 seconds turns the maxstream on, then goes to process and send the data, maintaining the 5-second loop timing. Finally at the end of the serial output statement add a turn-off of the line to put the maxstream back to sleep.

ASTER at 9600 baud
    84: Serial Out (P96)
     1: 52       Printer Comma/9600 Baud ;

85: Do (P86)
1: 53       Set Port 3 Low

Components:

XBee OEM: Maxstream zigbee networking 2.4Ghz module data sheet

XBee RF Modem: bundled modem data sheet

9Xtend OEM: Maxstream long-range radio 900Mhz module data sheet

9Xtend RF Modem: bundled modem data sheet

10W Solar Panel:

Morningstar SG4 PV controller: Proper charging of the batteries may not be necessary. For comparison sake we will try two sites with a controller instead of a simple blocking diode.