Xylem 4046 User Manual

Model 4046 SDI Sensor

Instruction Manual 60-0004046-00

1.0 INTRODUCTION

1.1. General Description:

The model 4046 SDI Sensor provides an interface to convert inputs from two
(2) analog sensors and one (1) tipping bucket to an SDI serial data interface.
The 4046 also provides internal measurements of battery voltage and
ambient temperature.

1.2. Specifications:

Size 3.5”LX0.75”WX2.1”H
Weight 1.9 oz.
Operating Temperature -30-60Degrees Centigrade
Power requirements 12 VDC
<200 uA during sleep

<1 A for sensor power

Mounting: Din Rail
Connections: Screw Terminal
Wire Size #24-#14 AWG
Inputs: Gnd, + 12VDC, (2) Analog 0- 5VDC

Tipping Bucket (contact closure to ground

Communication: SDI -12 (version1.1 compliant)
Sensor Power: 12VDC or 5.00VDC (jumper selectable)

2.0 OPERATION
The 4046 responds to all basic SDI commands. The sensor power is switched

on after successfully decoding a “Start Measurement” command and switched off at
the completion of the measurement. The duration (sensor warm-up time is
programmable using SDI commands. The 4046 will go into low power sleep state
when it is not being polled. User values for Slope (multiplier) and Offset (adder) are
programmable for both analog channels and tipping bucket. The tipping accumulator
can be set to zero by SDI command.

2.1. Connections:

Analog inputs from the (2) external sensors are connected to ANA in1
and ANAin2 respectively with the common (ground reference) connection at
ANA Gnd. Take care to observe polarity and limit the voltage input to 5V dc.
The input ANAin1 corresponds to SDI parameter 0 (first) and its Slope and
Offset values correspond to “A”. Input ANAin2 corresponds to SDI parameter
1 (second) and its Slope and Offset values correspond to “B”. The EVNT In
corresponds to SDI Parameter 2 (third) and its Slope and Offset correspond
to “C”. Sensor Power (either 12VDC or 5.00VDC) is switched on before the
Analog measurement takes place. The sensor warm-up time is user
programmable. External power sources for the sensor other than the

switched power may cause problems with the Analog measurement if
they are energized before the internal switched power is activated.

3.0 SDI COMMANDS
All input and response characters are in ASCII format, 1200 baud, even

parity.

‘a’ denotes the sensor address.
Note: If second command is sent to the sensor after starting a measurement,

but before the measurement is ready, the sensor will abort the measurement.
Acknowledge Active:

Returns a response acknowledging that the sensor unit is

active.
command a! sensor response a<CR><LF>

Send Identification:

Returns SDI version, company name, sensor model #, sensor version#.

command aI! sensor response allccccccccmmmmmmvvv<CR><LF>

II= SDI version ccccccc=8 character vender ID mmmmmm=6 character model
ID vvv= 3 character sensor version

Address Query:

Returns address for sensor. (Note Only one sensor may be on

the buss for this query)
command ?! sensor response a<CR><LF>

Start Verification: Returns a string that imitates a checksum.
command aV! sensor response a0011<CR><LF>

Change Address:

Change the address of the sensor unit. Valid addresses are

those in the range ‘O’ to ‘9’, A to Z’.
command aAb! sensor response b<CR><LF>

b is the new sensor address.

Start measurement

: The unit reads five sensor devices: two external analog

sensors, a tipping bucket counter, a battery voltage sensor, and an on-board
temperature sensor. These are divided into two measurement groups.

Group 1 contains data from the two analog sensors and the tipping bucket.
Group 2 contains data from the internal temperature sensor and battery
voltage.

To collect data from the group 1 sensors: command: aM!
sensor response: attt3<CR><LF>
3 Measurements will be ready in ttt seconds. Upon completion of the measurements
a service request will be issued. a<CR><LF>
To collect data from the Group 2 sensors: command: aM1!
sensor response A0012<CR><LF
2 Measurements will be ready in 1 second. Upon completion of the measurements a
service will be issued.

Send Data

: The format of the data is determined by the preceding command. If

Group 1 measurement results are being returned then data can contain three
numbers. If Group 2 measurement results are being returned then the data will
contain two numbers. All numbers in a data group are preceded with the sign of the
number, either ‘+’ or ‘-‘.

command aDO! sensor response axxxx…xx<CR><LF>
xxx.xx up to 32 characters

The input ANAin1 corresponds to SDI parameter o (first) and its Slope and Offset
values correspond to “A”. Input ANAin 2 correspond to SDI parameter 1 (second)
and it Slope and offset values correspond to “B”. The EVNT IN corresponds to SDI
parameter 2 (third) and its Slope and Offset correspond to “C’