Campbell 21X User manual

21X MICROLOGGER
OPERATOR'S MANUAL
REVISION: 8/95
CopynlcHT (c) 1994, 1995 CAMPBELL sclENTlFlc, lNc.

WARRANTY AND ASSISTANCE
The 21X MICROI-OGGER is warranted by CAMPBELL SCIENTIFIC, lNC. to be free from defects in
materials and wofkmanship under normal use and seruice for thifty-six (36) months from date of shipment
unless specified {thenrvise. Batteries have no warranty. CAMPBELL SCIENTIFIC, lNC.'s obligation under
this warranty is liririted to repairing or replacing (at CAMPBELL SCIENTIFIC, lNC.'s option) defective
products. The cugtomer shall assume all costs of removing, reinstalling, and shipping defective products
to CAMPBELL S0lENT|FlC, lNC. CAMPBELL SCIENTIFIC, lNC. will return such products by surface
carrier prepaid. {his warranty shall not apply to any CAMPBELL SCIENTIFIC, lNC. products which have
been subjected t{ modification, misuse, neglect, accidents of nature, or shipping damage. This warranty
is in lieu of all othtr warranties, expressed or implied, including warranties of merchantability or fitness for
a particular purp(se. CAMPBELL SCIENTIFIC, lNC. is not liable for special, indirect, incidental, or
consequential dafnages.
Products may nof be returned without prior authorization. To obtain a Returned Materials Authorization
(RMA), contact qAMPBELL SCIENTIFIC, lNC., phone [phone]. After an applications engineer
determines the n{ture of the problem, an RMA number will be issued. Please write this number clearly on
the outside of thN shipping container. CAMPBELL SCIENTIFIC's shipping address is:
CAMPBELL SCIENTIFIC, INC.
FtMA#_
815 West 1800 North
l*ogan, Utah 84321 -1 784
CAMPBELL SCIENTIFIC, lNC. does not accept collect calls.
Non-warranty pr{ducts returned for repair should be accompanied by a purchase order to cover the repair.
GAI\/|PEIELL SiCIEN'rIFIC, INC.
815 W. 1800 N.
Logan, UT 84321-1784
USA
Phone (8O1) 753-2342
FAX (8O1) 7sO-954O
Campbell Scientific Canada Corp.
I 1564 -149th Street
Edmonton, Alberta TsM 1W7
CANADA
Phone (4O3) 454-2505
FAX (4O3) 454-2655
Campbell Scientilic Ltd.
14-2o Field Street
Shepshed, Leics. LEl2 gAL
ENGLAND
Phone [phone]
FAX [phone]O91

21X OPERATOR'S MANUAL
TABLE OF CONTENTS
PAGE
WARRANW AND ASSISTANCE
SELECTED OPERATING DETA1LS............ .......'................ v
CAUTIONARY NOTES............. ...'..... vl
OVERVIEW
OV1. PHYSICAL DESCRIPTION
OV1.1 Arlalog Inputs .'..OV-2
OV1.2 Switched Excitation Outputs...... ........'.'... OV-3
OV1.3 Continuous Analog Outputs ' OV-3
OV1.4 Dibital Control Ports .......... '.. OV-3
OV1.5 PUIse Count lnputs ..'.'..........OV-3
OV1.6 14 Volts and Ground ..."......' OV-3
ov2. MEI/|oRY AND PROGRAMMING CONCEPTS
OV2.1 lniernal Memory '...........'.....'OV-3
OV2.2 2lX Instruction Types... .....'.. OV-s
OV2.3 P{ogram Tables and the Execution and Output Intervals ...-.-....... OV-5
OV3. PROGRAMMING THE 21X
OV3.1 Fdrnctional Modes ......'..'...'..' OV-7
OV3.2 Kbv Definition ................ ....." OV-7
OV3.3 Pfogramming Sequence .....' OV-7
OV3.4 lrlstiuction Format '...........'..' OV-8
OV3.5 Entering a Program '............. OV-8
OV4. PHOGRAMMING EXAMPLES
OV4.1 Shmple Program 1 ................ '.......'...'..... OV-g
OV4.2 ebiting an Existing Program OV-11
OV4.3 Sbmpie Program 2................ oV-12
ovs. DATA RETRIEVAL OPT1ONS............ ov-15
ov6. sPEclFlcATloNs ov-18

2.1
2.2
2.3
TABLE OF CONTENTS
PROGRAMMING
1. FUNCTIONAL MODES
Setting and Displaying the Clock - *5 Mode .................. 1-
Displaying and Altering Input.Mernory or Flags -*6 Mode ............-..1-
Compiling and Logging Data - *0 Mode ........................1
Memory Allocation - *A............. ..................'l
Memory Testing and System Status - *B Mode ............ 1
C Mode - Security.... ................1
*D Mode - Save or Load Program .............. 1-
On-Line Data Transfer - Instruction 96, *4 Mode ..........4-1
Manually lnitiated Data Output - "8 and *9 Modes ........4-2
Cassette Tape Option .............4-4
Storage Module (SM192l716) ................. ......................4-6
Printer Output Formats...... ......4-7
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
4.1
4.2
4.3
4.4
4.5
2. INTERNAL DATA STORAGE
Final Storage Areas, Output Arrays, and Memory Pointers .............2-1
Data Output Format and Range Limits .....,... ................2
Displaying Stored Data on Keyboard/Display - *7 Mode ..................2
3. INSTRUCTION SET BASICS
Parameter Data Types ............3-1
Repetitions. ...........3-1
Entering Negative Numbers .......................3-1
Indexing Input Locations ............... .............3-1
Voltage Range and Overrange Detection .....................3-2
Output Processing. ..................3-2
Use of Flags: Output and Program Control ..................3-3
Program Control Logical Constructions................. ........3-4
Instruction Memory and Execution Time...... .................3-6
Error Codes ..........3-9
DATA R ETRI EVAUCOM M U N ICATIO N
4. EXTERNAL STORAGE PERIPHERALS
5.1
5.2
5. TELECOMMUNICATIONS
6.
6.1
6.2
6.3
6.4
6.5
Telecommunications Commands. ..............5-1
Remote Programming of the 21X............. .....................5-3
9 PIN SERIAL INPUT/OUTPUT
Pin Description.............. ..........6-1
Enabling Peripherals ...............6-2
f nterrupting Data Transferto Storage Peripherals................ ...........6-2
Telecommunications - Modem Peripherals. ..................6-2
Interfacing with Computers, Terminals, and Printers ....6-2

TABLE OF CONTENTS
PROGRAMMING EXAMPLES
REMENT PROGRAMMING EXAMPLES
Voltage - Ll200S Silicon Pyranometer................. ..........7-1
and Sensor with a Common External Power Supply .....7-1
Temperatures Using 21X Reference.............. .........7-2
107 Temperature Probe ..........7-3
207 Temperature and RH Probe... .............7-3
Ademometer with Photochopper Output ....7-4
Tipping Bucket Rain Gauge with Long Leads ...............7-4
100 ohm PRT in 4 Wire Half Bridge. ..........7-5
100 ohm PRT in 3 Wire Half Bridge. ..........7-6
100 ohm PRT in 4 Wire Full Bridge.. .........i......... ..........7-7
Prlessure Transducer - 4 Wire Full Bridge.. ...................7-8
Llsimeter - 6 Wire Full Bridge.. ..................7-9
227 Gypsum Soil Moisture Block ............. 7-10
N$nlinear Thermistor in Half Bridge (CSl Model 101)............ ........7-11
Mtasuring 107 Temperature Probe with 60Hz Rejection.... ..,........7-12
PRObESSING AND PROGRAM CONTROL EXAMPLES
CQmputation of Running Average ..............8-1
Rdinfall Intensity ......................8-2
U$ing Control Ports and Loop to Run AM416 Multiplexer. ...............8-3
SIUB 1 Minute Output lnterval Synched to RealTime.......... ............8-5
SpM-AO4 Analog Output Multiplexer to Strip Chart ......... ............... 8-5
CQnverting 0-360 Wind Direction Output to 0-540 for Strip Chart.......... .............8-7
CQvariance Correlation Programming Example.. ..........8-8
FAst Fourier Transform Examples ........... 8-11
PAGE
7.
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
7.'to
7.11
7.12
7.13
7.14
7.15
7.16
8.
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
10.
INSTRUCTIONS
9. INPUT/OUTPUT INSTRUCTIONS..... ................... e-1
11. OUTPUT PROCESSING |NSTRUCT|ONS...,............ ......... 11-1
12. PROGRAM CONTROL INSTRUCTIONS .........12-1
MEASUREMENTS
13. 21X MEASUREMENTS
13.1 Fast and Slow Measurement Sequence .. 13-1
13.2 Single-Ended and DifferentialVoltage Measurements............ ....... 13-1
13.3 Tfre Effect of Sensor Lead Length on the Signal Settling Time.......... .............. 13-3
13.4 Tfrermocouple Measurements........... .... 13-10
13.5 Biidge Resistance Measurements.............. .............. 13-15
13.6 Rpsistance Measurements Requiring AC Excitation............. .......'t3-19
ill

TABLE OF CONTENTS
INSTALLATION
14. INSTALLATION AND MAINTENANCE
14.1
14.2
14.3
'14.4
14.5
14.6
14.7
14.8
14.9
14.10
Solar Pane1s................. ......... 1
Direct Battery Connection to the 21X............ .............. 1
Vehicle Power Supply Connections .......... 1
Use of DigitalControl Ports for Switching Relays...,.... ................... 14
Grounding.. .........14
Maintenance................. .........14
Calibration Procedures. ......... 1
APPENDICES
GLOSSARY................ ............A-1
PROM SIGNATURES AND SOFTWARE OPT|ONS............. ...............B-1
BINARY TELECOMMUNICATIONS
Telecommunications Command With Binary Responses. ...............C-1
FinalStorage Format..... ..........C-3
Generation of Signature ..........C-4
ASCII TABLE.... .....................D-1
CHANGING RAM OR PROM CHIPS
Disassembly of 21X...... ........... E-1
Installing New RAM Chips.......... ................ E-1
Changing PROM Chips......... .....................E-2
DOCUMENTATION FOR SPECIAL SOFTWARE............. .................... F-1
A.
B.
c.
c.1
c.2
c.3
D.
E.
E.1
E.2
E.3
F.
LIST OF TABLES.. ....... Lr-1
LIST OF FIGURES ....... LF-1
tv

I
I
I
I
I
I
I
l
i
I SELECTED OPERATING DETAILS
I
I
I
1. StorinolData - Data is stored in Final PROMs are available which have different
Storag-{ only by Output Processing combinations of instructions. Appendix B
Instruiiions and only when the Output Flag describes the options available and gives
is set. i(Sections OV2 and OV3.3) the signatures of the current PROMS.
3. Data Tians{er - On-line data transfer f rom INSTRUCTIONS
Final Qtorage to peripherals (tape, printer,
Storagp Mo.-dule,'etc.)occurs onty if enabied Case Statement (83 & 93, Section 12)
with Inptruction 96 in the datalogger
prografn or in the *4 Mode. (se-clion +.t) Arc Tangent (66 Section 10)
2. Storing Date and Trme Date and time are
stored in Final Storage ONLY if the Reat
Time lrlrstruclionTT is used. (Section 11)
Final $torage Resolution - All Input Storage
values]are displayed ("6 mode) as high
resolulion with a maximum value ol99999.
Howerier, the default resolution for data
stored in FinalStorage is low resolution,
maxin'lum value of 6999. Results
exceefling 6999 are stored as 6999 unless
InstruOtion 78 is used to store the values in
Final $torage as high resolution values.
(Sections 2.2.1 and 11\
Floatirlrg Point Format - The computations
pedorfned in the 21X use floating point
arithnletic. CSI's 4 byte floating point
numbFrs contain a 23 bit binary mantissa
and a16 bit binary exponent. The largest
and srinallest numbers that can be stored
and piocessed are 9 x 1018 and 1 x 10'1e,
respeptively. (Section 2.2.2)
Erasinrg Final Storage Data in Final Storage
can be erased without altering the program
by repartitioning memory in the'A Mode.
(Section 1.5.2)
ALL memory can be erased and the 21X
completely reset by entering 978 for the
numler of bytes left in Program Memory.
(Section 1.5.2)
The set of instructions available in the 21X
is delermined by the PROM (Programmable
Read Only Memory)that it is equipped with.
9. Significant changes in the current PROM
release (OSX-0.1 , OSX-1 .1 , and OSX'2.1)
include:
Wind Vector (69 replaces 76, Section 1 1)
Serial Output has an option to send a file mark
to a Storage Module (96, Section 12)
Low Pass Filter: on the first execution after
compiling, the input value is used for the filtered
result
Commands to set, toggle and pulse porls are
now available for Program Control Instructions
(Section 12)
Revision 3 of the above PROMS includes the
capability to sense status(O V low, 5 V high) on
the high side of a differentialchannel
(lnstruction 91 , Section 12).
FEATURES
Ports can now be manually toggled from the
keyboard or TERM (PC208 software)
The.B Mode now displays PROM version and
revision, execution overruns, and accumulated
error 8s in addition to signatures.
The capability of transferring programs via
cassette tape is no longer supported in the
standard PROM options.
4.
5.
o.
7.
8.

CAUTIONARY NOTES
2.
Damage will occur to the analog input
circuitry if voltages in excess of r16 V are
applied for a sustained period. Voltages in
excess of t8V will cause errors and
possible overranging on other analog input
channels.
There are frequent references in this
manualto Storage Modules. The Storage
Modules referred to are the SM192 and
SM716. The old SM16 and SM64 Storage
Modules cannot pedorm many of the
functions available with the SM192 and
sM716.
?The sealed lead acid batteries u
21XL are permanently damaged if
discharged below 11.76 V. The cel
rated at a 2.5 Ahr capacitv but
slow discharge even in storage. lt i
advisable to maintain a continuous
on the 21XL battery pack, whether
operation or storage (Section 14).
vl

21 X MICROLOGGER OVERVIEW
The 21X Mi ologger combines precision measurement with processing and control capability in a single
battery oper ted system.
Campbell SQientific, lnc. provides three documents to aid in understanding and operating the 21X:
1. This Overuiew
2. 1 The 21X Operator's Manual
3. I fne 21X Prompt Sheet
i
This Overui$w introduces the concepts required to take advantage of the 21X's capabilities. Hands-on
programmin! examples start in Section OV4. Working with a 21X will help the learning process, so don't
just read tha examples, turn on the 21X and do them. lf you want to staft this minute, go ahead and try
the exampldp, then come back and read the rest of the Overview.
The sectiong of the Operator's Manualwhich should be read to complete a basic understanding of the
appropriate are the Programming Sections 1-3, the portions of the data retrieval Sections 4 and 5
the method(s) you are using (see OVS), and Section 14 which covers installation and
Section 6details of serialcommunications. Sections 7 and I contain programming examples.
Sections 9- have detailed descriptions of the programming instructions, and Section 13 goes into
detailon 2 1 X measurement procedures.
The Sheet is an abbreviated description of the programming instructions. Once familiar with the
21X, it is to program it using only the Prompt Sheet as a reference, consulting the manual if
further is needed.
Read the SQlected Operating Details and Cautionary Notes at the front of the Manual before using the
21X.
OV1. PHYSIDAL DESCRIPTION
The 21X Mifrologger is shown in Figure OV1-1.
The 21X is powered with 8 alkaline "D" cells
and has onlf the power switch on the base.
The 21XL ig powered with rechargeable lead
acid cells add, in addition to the power switch,
has a chargpr input plug and an LED which
lights when fhe charging circuit is active. The
21XL shoulfl always be connected to a solar
panel or AC charger. The lead acid batteries
provide bacfiup in event of a power failure but
are permanpntly damaged if their voltage drops
below 11.74 volts. Campbell Scientific does not
warrant bafleries. The battery base is the only
difference between the 21X and the 21XL.
The 16 chafacter keyboard is used to enter
programs, qommands and data;these can be
viewed on tfie 8 digit display (LCD). FIGURE OV1-1. 21X Micrologger
ov-1

21 X MICROLOGGER OVERVIEW
The 9-pin serial l/O port provides connection to
data storage peripherals, such as the
SM192t16 Storage Module or RC35 Cassette
Recorder, and provides serial communication to
computer or modem devices for data transfer or
remote programming (Section 6). This 9 pin port
does NOT have the same pin configuration as
the 9 pin serial ports currently used on many
personalcomputers. An SC32A is required to
OVl.l ANALOG INPUTS
The terminals in the upper strip are for analog
inputs. The numbering on the terminals refers to
the diflerential channels; i.e., the voltage on the
Hl input is measured with respect to the voltage
on the LOW input. When making single-ended
measurements either the Hl or the LOW channel
may be used independently to measure the
voltage with respect to the 21X ground. Single-
ov-2
interface the 21X to a RS232 serial port
(Section 6).
The panel also contains two terminal strips
which are used for sensor inputs, excitation,
control outputs, etc. Figure OV1-2 shows the
21X panel and the associated programming
instructions.
ended channels are numbered sequentially, e
the Hl and LOW sides of differential channel2
are single-ended channels 3 and 4, respectively
(Section 13.2).
The analog input terminal strip has an insulated
cover to reduce temperature gradients across
the input terminals. The cover is required for
accurate thermocouple measurements (Section
13.4).
FfGURE OVl-z. 21X Wiring Paneland Associated Programming Instructions
SERI L I,/o
Tclccommunlcotlons
Progrom Control Instructlons
96 (Tcpe, Storog€ Module, Printer)
97 Initiotc Telecommunicotions
9E Print Chorocter
Input,/Output
Progrom Cont
91 lf
92 lf
Comqnd
'f2J15C7E
ETCITATION OI'TUTS
Input/Output Instructions
4. Ex-Dcl-Se
5. AC Holf Br
6. Full Br
7. 5W Holf Br
8. Ex-Del-Dlff
9. Full Br-Mcx
11.Temp(107)
12 RH (2o7)
22. Exclt-Del
EEE
tr1 EE
EE
rilE
ANAIOG INPIIIS
Input/Output Instructions
1. Volt (SE)
2. vott (uFF)
4. Ex-Del-Sc
5. AC Holf Br
6. Full Br
7. 5W Holf Br
E. Ex-Del-Dlff
9. Full Br-Mox
11 Temp (107)
12 RH-(2O7)
15. Tcmp-TC SE
14. Temp-TC DIFF
17. Tcmp-Poncl

ovl.2 EXCITATION OUTPUTS
The first fou numbered terminals on the lower
are the SWITCHED EXCITATION
terminal supply programmable
for resistive bridge
ts. The excitation channels are
only on during the rneasurement.
ovl.3 ANALOG OUTPUTS
The two Codtinuous Analog Output (CAO)
channels suSply continuous output voltages,
under program control, for use with strip charts,
X-Y plotters, or proportional controllers.
OV1.4 DIGITAI..J CONTROL PORTS
The six DIGI1TAL CONTROL PORTS (0 or 5
volt states) allow on-off controlof external
devices. Thfse control potts have a very
limited curreht output (5 mA) and are used to
switch solid State devices which in turn provide
power to rel{y coils (Section 14.4).
OV1.5 PULSE OOUNT INPUTS
The four PULSE COUNT INPUTS measure
contact clos{re, low levelAC, or high frequency
pulse signal$.
periods in the field.
OV2. MAND PROGRAMMING
coNc
The 21X be programmed before it will
A program consists
. 21X MICROLOGGER OVERVIEW*
table. The program table is given an execution
intervalwhich determines how frequently that
table is executed. When the table is executed,
the instructions are executed in sequence from
beginning to end. After executing the table, the
21X waits the remainder of the execution
interval and then executes the table again
starting at the beginning.
The interualat which the table is executed will
generally determine the intervalat which the
sensors are measured. The interval at which
data are stored is separate and may range from
samples every execution interval to processed
summaries output hourly, daily, or on longer or
irregular intervals.
Figure OV2-1 represents the measurement,
processing, and data storage sequence in the
21X and shows the types of instructions used to
accomplish these tasks.
OV2.1 INTERNAL MEMORY
The 21X has 40,960 bytes of Random Access
Memory (RAM), divided into five areas. The
five areas of RAM are:
1. Input Storage - Input Storage holds the
results of measurements or calculations.
The *6 Mode is used to view Input Storage
locations to check current sensor readings
or calculated values. lnput Storage defaults
to 28 locations. Additional locations can be
assigned using the "A Mode.
2. Intermediate Storage - Certain Processing
Instructions and most of the Output
Processing Instructions maintain
intermediate results in Intermediate
Storage. Intermediate storage is
automatically accessed by the Instructions
and cannot be accessed bythe user. The
default allocation is 64 locations. The
number of locations can be changed using
the *A Mode.
channels.
excitation
make any
of a group instructions entered into a program
connection tb the 21X power supply. The +12
and ground ferminals can be used to connect
an external f 2 volt battery to the 21X to
ov-3

INPUT/OUTPUT
INSTRUCTIONS
Specify the conversion of a sensor signal to a
data value and store it in Input Storage.
Programmable entries specify:
(1) the measurement type
(2) the number of channels to measure
(3) the input voltage range
(4) the Input Storage Location
(5) the sensor calibration constants used to
convert the sensor output to engineering
units
l/O Instructions also control analog outputs
and dioital control
Sensor
Control
21X MICROLOGGER OVERVIEW
PROCESSING INSTRU CTION S
Perform calculations with values in Input
Storage. Results are returned to Input
Storage. Arithmetic, transcendental and
are
FIGURE OV2-1. lnstruction Types and Storage Areas
INTERMEDIATE STORAGE
Provides temporary storage for
intermediate calculations required by the
OUTPUT PROCESSING
NSTRUCTIONS; for example, sums,
OUTPUT PROCESSING
INSTRUCTIONS
Perform calculations over time on the values
updated in Input Storage. Summaries for Final
Storage are generated when a Program
Control Instruction sets the Output Flag in
response to time or events. Results may be
redirected to Input Storage for further
processing. Examples include sums,
averages, ma)dmin, standard deviation,
set high
FINAL STORAGE
Final results from OUTPUT PROCESSING
INSTRUCTIONS are stored here for on-line or
interrogated transfer to e)dernal devices
(Figure OV5.1-1). The newest data are stored
over tn
ov-4

3. Final
stored
The use of
Storage in
processing
While the
constant,
the areas
Section 1
memory,
progranfs entered in Program Tables 1 and
2, and $ubroutine Table 3. (Sections OV3,
1.1)
state Module or for retrieval via
links. Values are stored
in Final only by the Output
Output
19,296
power
Instructions and only when the
is set in the users program. The
allocated' to Final Storage at
is reduced if Input or Intermediate
is increased.
Systeni Memory - used for overhead tasks
such as] compiling programs, transferring
data, etb. The user cannot access this
ge - Final, processed values are
for transfer to printer, tape, solid
Input, Intermediate, and Final
measurement and data
is shown in Figure OV2:1.
size of these three areas remains
may be reallocated between
accommodate different
t and processing needs (*A Mode,
The size of system and program
fixed.
21X MICROLOGGER OVER\NEW
used to develop high level algorithms to
process measurements prior to Output
Processing (Section 1 0).
OUTPUT PROCESSING INSTRUCTIONS
(69-82, Section 1 1) are the only instructions
which store data in Final Storage
(destination). Input Storage (source) values
are processed over time to obtain averages,
maxima, minima, etc. There are two types
of processing done by Output Instructions:
Intermediate and Final.
Intermediate processing normally takes
place each time the instruction is executed.
For example, when the Average Instruction
is executed, it adds the values from the
input locations being averaged to running
totals in lntermediate Storage. lt also keeps
track of the number of samples.
Final processing occurs only when the
Output Flag is high. The Output Processing
Instructions check the Output Flag. lf the
flag is high, finalvalues are calculaled and
output. With the Average, accumulated
totals are divided by the number of samples
and the resulting averages sent to Final
Storage. lntermediate locations are zeroed
and the process stafts over. The Output
Flag, Flag 0, is set high by a Program
Control Instruction which must precede the
Output Processing Instructions in the user
entered program.
PROGRAM CONTROL INSTRUCTIONS
(85-98, Section 12) are used for logic
decisions and conditional statements. They
can set flags, compare values or times,
execute loops, call subroutines, conditionally
execute portions of the program, etc.
OV2.3 PROGRAM TABLES AND THE
EXECUTION AND OUTPUT INTERVALS
Programs are entered in Tables 1 and 2.
Subroutines, called from Tables 1 and 2, are
entered in Subroutine Table 3. The size of each
table is flexible, limited only by the total amount
of program memory. lf Table 1 is the only table
programmed, the entire program memory is
available for Table 1.
Table 1 and Table 2 have independent
execution intervals. entered in units of seconds
ov2.2 21Xl
Figure 1 illustrates the use of the three
act on data. The
used to control
different iion types which
fouilh type, Control, is
output ti and vary program execution.
are identified by numbers.
1. rNPUT/OUTPUT TNSTRUCTTONS (1-
26,101-104, Section 9) controlthe terminal
strip inputs and outputs (the sensor is the
source, Figure OV1-2), storing the results in
Input Sprage (destination). Multiplier and
offset pBrameters allow conversion of linear
signals into engineering units. The Control
Ports and Continuous Analog Outputs are
also addressed with l/O lnstructions.
2. PROCqS$NG TNSTRUCTTONS (30-66,
Sectionr 1 0) perform numerical operations
on valups located in Input Storage (source)
and stofe the results back in Input Storage
(destin4tion). These instructions can be
4.
ov-5

Table 1.
Execute every x sec.
0.0125<x<6553
Instru ctions are executed
sequentially in the order
they are entered in the
table. One complete pass
through the table is made
each execution interual
unless program control
instructions are used to
or branch execution.
NormalOrder:
MEASURE
PROCESS
CHECK OUTPUT COND.
PUT PROCESSING
21X MICROLOGGER OVERVIEW
with an allowable range of 0.0125 to 6553
seconds. Intervals shorter than 0.1 seconds
are allowed only in Table 1. Subroutine Table 3
has no execution interval; subroutines are only
executed when called from Table 1 or 2.
OV2.3.1 THE EXECUTION INTERVAL
The execution interval specifies how often the
program in the table is executed, which is
usually determined by how often the sensors are
to be measured. Unless two different
measurement rates are needed, use only one
table. A program table is executed sequentially
starting with the first instruction in the table and
proceeding to the end of the table.
Each instruction in the table requires a finite
time to execute. lf the execution interval is less
than the time required to process the table, the
21X overruns the execution interval, finishes
processing the table and waits for the next
execution interval before initiating the table.
When an overrun occurs, decimal points are
shown on either side of the G on the display in
the LOG mode (.0). Overruns and table priority
are discussed in Section 1.1.
FIGURE OV2.2. Program and Subroutine Tables
OV2.3.2 THE OUTPUT
The interval at which oul
independent from the ex
than the fact that it must
executed (i.e., a table ce
execution interval and or
A single program table c
output intervals and conr
unique data set (output i
Instructions are used to
which determines when
Output Processing Instrt
instruction setting the Or
data output and its sequ,
output array is created b
Control Instruction settin
in response to an output
Output Processing Instrt
set to output.
OV3. PROGRAMMING
A program is created by
datalogger or on a PC ur
Datalogger Support Soft
This manualdescribes d
able 2.
Execute every y sec.
1 <v<6553
Table 2 r.s used if there is a
need to measure and
process data on a separate
interualfrom that in Table
1.
ov-6
Table 3.
Subroutines
A subroutine is executed
only when called from
Table I or 2.
Subroutine Label
lnstructions
End
Subroutine Label
Instructions
End
Subroutine Label
lnstructions
End
TPUT INTERVAL
ch output occurs is
the execution interval, other
I must occur when the table is
rble cannot have a 10 minute
and output every 15 minutes)
able can have many different
d conditions, each with a
utput array). Program Contro
ied to set the Output Flag
when output occurs. The
I Instructions which follow the
the Output Flag determine thr
i sequence. Each additional
ated by another Program
setting the Output Flag high
rutput condition, followed by
I Instructions defining the dati
MING THE 21X
ed by keying it directly into th,
PC using the PC208
rt Software program EDLOG.
'ibes direct interaction with thr

21X. Work the direct programming
examples in
and you will overuiew before using EDLOG
the basics ol21X operation as
wellas an ion for the help provided by Key
the Section OV3.5 describes options
for loading program into the 21X.
OV3.1 FUNCTIONAL MODES
User interaction with the 21X is broken into
different fun$tional MODES, (e.9., programming
the measurdments and output, setting time,
manually ini{iating a block data transfer to
*4 Efrable/disable tape and/or printer
output
21X MICROLOGGER OVERVIEW
TABLE OV3-2. Key Description/Editing
Functions
Action
0-9 Key numeric entries into display
* Enter Mode (followed by Mode
Number)
A Enter/Advance
B Back up
C Change the sign of a number or index
an input location to loop counter
D Enter the decimal point
# Clear the rightmost digit keyed into
the display
#A Advance to next instruction in
program table (-1 , *2, *3) or to next
output array in Final Storage (.7)
#B Back up to previous instruction in
program table or to previous output
array in FinalStorage
#D Delete entire instruction
OV3.3 PROGRAMMING SEOUENCE
ln routine applications, sensor signals are
measured, processed over some time interual,
and the results are stored in Final Storage. A
generalized programming sequence is:
1. Enter the execution interval, determined by
the desired sensor scan rate.
2. Enter the InpuUOutput Instructions required
to measure the sensors.
Enter any Processing lnstructions required
to get the data ready for Output Processing.
Enter a Program Control Instruction to test
the output condition and Set the Output
Flag when the condition is met. For
example, use lnstruction 92 to output based
on time, 86 to output each time the table is
executed, and 88 or 89 to compare input
values. This instruction must precede the
Output Processing Instructions.
Enter the Output Processing Instructions to
store processed data in FinalStorage. The
order in which the data are stored is
determined by the order of the Output
Processing lnstructions in the table.
Repeat steps 4 and 5 for output on different
intervals or conditions.
*5
*6 realtime clock
lnput Storage data,
flags
FinalStorage data
Storage data transfer to
tape
Storage data transfer to printer
allocation/reset
re tesVPROM version
*9
*A
*B
*c
*D 4.
velload P
OV3.2 KEY
Keys and
functions sequences have specific
using the 21X keyboard or a
ter in the remote keyboard state
(Section 5). Table OV3-2 lists these functions.
ln some the exact action of a key
depends the mode the 21X is in and is
described the mode in the manual.
etc.). The modes are referred
to as Star (") Modes since they are accessed by
first keying *, then the mode number or letter.
Table OV3-1 lists the 21X Modes.
OV3-1. * Mode Summary
data and indicate active Tables
ram Table 1
m Table 3, subroutines only
ov-7

21 X MICROLOGGER OVERVIEW
OV3.4 INSTRUCTION FORMAT
Instructions are identified by an instruction
number. Each instruction has a number of
parameters that give the 21X the information it
needs to execute the instruction.
The 21X Prompt Sheet has the instruction
numbers in red, with the parameters briefly
listed in columns following the description.
Some parameters are footnoted with further
description under the "lnstruction Option Codes"
heading.
For example, lnstruction 73 stores the
maximum value that occurred in an Input
Storage Location over the output interval. The
instruction has three parameters (1)
REPetitionS, the number of sequential lnput
Storage locations on which to find maxima, (2)
TIME, an option of storing the time of
occurrence with the maximum value, and (3)
LOC the first Input Storage Location operated
on by the Maximum Instruction. The codes for
the TIME parameter are listed in the "lnstruction
Option Codes".
The repetitions parameter specifies how many
times an instruction's function is to be repeated.
For example, four 107 thermistor probes, wired
to single-ended channels 1 through 4, are
measured using a single Instruction 11, Temp-
107, with four repetitions. Parameter 2
specifies the input channel of the first thermistor
(channel 1) and parameter 4 specifies the Input
$torage Location in which to store
measurements from the first thermistor. lf
Location 5 were used, the temperature of the
thermistor on channel 1 would be stored in lnput
Location 5, the temperature from channel2 in
Input Location 6, etc.
Detailed descriptions of the instructions are
given in Sections 9-12.
OV3.5 ENTERING A PROGRAM
Programs are entered into the 21X in one of
four ways:
1. Keyed in using the 21X keyboard.
2. Loaded from a pre-recorded listing using
the *D Mode. There are 2 types of
storage/input:
Stored on disl</sent from computer
(PC208 software TERM and EDLOG).
Stored/loaded f rom SM1 92t1 6
Module
3. Loaded from Storage Module or internal
PROM (special software) upon power-up.
A program is created by keying it directly into
the datalogger as described in the following
Section, or on a PC using the PC208
Datalogger Support Software.
EDLOG and TERM are PC208 Software
programs used to develop and send programs
to the 21X. EDLOG is a prompting editor for
writing and documenting programs for Campbe
Scientific dataloggers. Program files developed
with EDLOG can be downloaded directly to the
21X using TERM. TERM supports
, communication via direct wire, telephone, or
Radio Frequency (RF).
Programs on disk can be copied to a Storage
Module with SMCOM. Using the *D Mode to
save or load a program from a Storage Module
is described in Section 1.8.
lf the SM192/716 Storage Module is connected
when the 21X is powered-up the 21X will
automatically load program number 8, provided
that a program 8 is loaded in the Storage
Module (Section 1.8).
It is also possible (with special software) to
create a PROM (Programmable Read Only
Memory) that contains a datalogger program.
With this PROM installed in the datalogger, the
program willautomatically be loaded and run
when the datalogger is powered-up, requiring
only that the clock be set.
OV4. PROGRAMMING EXAMPLES
We willstart with a simple programming
example. There is a brief explanation of each
step to help you follow the logic. When the
example uses an instruction, find it on the
Prompt Sheet and follow through the
of the parameters. Using the Prompt Sheet
while going through these examples will help
you become familiar with its format. Sections 9-
12 have more detailed descriptions of the
instructions.
a.
b.
ov-8

OV4.1 SAMPLE PROGRAM 1
I
The 21X ha$ a thermistor built into the input
panelthat nieasures the paneltemperature and
provides a rlference for thermocouple
temperaturel measurements. In this example
21X MICROLOGGER OVERVIEW
the 21X is programmed to read the panel
temperature every 5 seconds and send the
results directly to Final Storage.
TURN ON THE POWER SWITCH AND
PROCEED AS INDICATED
Key Display Shows
(lD:Data) Explanation
HELLO On power-up, the 21X displays "hello" while it
checks the memory.
after a few seconds delay
11:111111 The result of the memory check. Each digit
represents a memory socket on the CPU board.
1's indicate good memory, 0's bad memory
(Section 1.5).
Select mode.
Enter Program Table 1.
Advance to execution interval (seconds).
Key 5 second execution interval.
Enter the 5 second execution interval and advance
to the first program instruction location. The 21X
prompts with a P when it is time to enter an
instruction number.
Key in l/O Instruction 17, measure the panel
temperature in degrees C.
Enter lnstruction 17 and advance to the first
parameter.
Key in the Input Storage location in which to store
the measurement; location 1.
Enter the location number. Note that the 21X
knows how many parameters are associated with
an instruction and will prompt for a new instruction
I number when parameter entry is completed.
Th4 21X is now programmed to read the panel temperature every five seconds and place
thetreading in lnput Storage location l. Before adding any more instructions, we will start the
propram and display the measurement in lnput Storage.
1
A
5
A
17
A
00:00
01:00
01:0.0000
01:5
01:P00
01:P17
01:0000
1 01:1
A 02:P00
ov-9

21 X MICROLOGGER OVERVIEW
Key
"0
"6
A
Explanation
Exit Table 1, enter *0 mode to compile table and
begin measurements.
Enter *6 mode to view Input Storage.
Advance to Input Storage location 1. Panel
temperature is 21 .234oC.
Explanation
Exit *6 mode. Enter Program Table 1.
Advance to 2nd instruction location; this is where
we left off. Note how we jumped to the 2nd
instruction instead of just advancing by keying A.
86 is the DO instruction; a Program Control
lnstruction which unconditionally executes a
command.
Enter instruction and advance to the first
parameter specifying the command.
10 is the command to set Flag 0, the Output Flag.
The command codes are listed in the lnstruction
Option Codes for Instructions 86-92 on the
Sheet and in Table 12.1-2.
Enter the command and advance to third program
instruction location.
The Output Processing Instruction, SAMPLE,
transfers values from Input Storage to Final
Storage when the Output Flag is set.
Enter 70 and advance to first parameter specifying
the repetitions.
There is only one value to sample so only one
repetition is entered.
Wait a few seconds:
O1:21.423 The measurement will be updated every 5
seconds when a new measurement is made.
At this point the 21X is measuring the temperature every 5 seconds and sending the value
to Input Storage. No data are being saved. The nert step is to have the 2lX send each
reading to Final Storage. (Remember the Output Flag must be set first.)
Display Shows
(lD:Data)
:LOG 1
06:0000
01:21.234
Display Shows
(lD:Data)
01:00
02:P00
02:P86
01:00
01:10
03:P00
03:P70
01:00
01:1
Key
*1
2A
86
A
10
A
70
A
ov-l0

21X MICROLOGGER OVERVIEW
Display Shows
Key (lD:Data) Explanation
A 02:0000 Enter repetition and advance to the second
parameter which specifies the first lnput Storage
location to sample.
1 O2:1 lnput Storage location 1, where the panel
temperature is stored.
A 04:P00 Enter location and advance to fourth instruction
location. Note that a value is not entered into
i memory untilA is keyed. lf *0 was keyed after the
] 1 in the previous step, the location would not be
] "ntered and would remain 0.
I *0 :LOG 1 Exit Table 1, enter "0 mode, compile program, and
] log data.
I
The 21X is fow programmed to measure the paneltemperature every 5 seconds and send each
reading to Ffalstorage. Values in Final Storage can be viewed using the *7 Mode (Section 2.3):
I Display Shows
Key (lD:Data) Explanation
*7 07: 13.000 Enter *7 Mode. The Data Storage Pointer (DSP) is
displayed showing the next available Final Storage
Location (location 13 in this example).
A 01: 0102 Advance to the first value, the output array
ldentifier (lD). The lD indicates the Output Flag
was set in Table 1 by the second instruction
(Section 2.1).
A 02:21.23 Advance to the first temperature stored. Note that
there are only 4 digits displayed (low resolution)
while the readings in Input Storage displayed 5
digits (Section2.2 and lnst.78).
A 01: 0102 Advance to the next output array. Same output
array lD.
A 02:21.42 Advance to 2nd stored temp.
*0 :LOG 1 Change to *0 Mode.
ln the abovq example, no time information is stored with the data. ln the second example,
lnstruction 77 is used to save the time of the measurements.
OV4.2 EDITING AN EXISTING PROGRAM
When editing an existing program in the 21X,
entering a npw instruction inserts the
instruction; fntering a new value for an
instruction flarameter replaces the previous
To insert an instruction, enter the program table
and advance to the position where the
instruction is to be inserted (i.e., P in the data
portion of the display) key in the instruction
number, and then key A. The new instruction
value.
ov-l1

21X MICROLOGGER OVERVIEW
will be insefted at that point in the table,
advance through and enter the parameters.
The Instruction that was at that point and al
instructions following it will be pushed down to
follow the inserted instruction.
An instruction is deleted by advancing to the
instruction number (P in display) and keying #D
(Table OV3-2).
To change the value entered for a parameter,
advance to parameter and key in the correct
value then key A. Note that the new value is
entered untilA is keyed.
The next example program uses the panel
temperature measurement but uses timed
intervals for output instead ol every execution.
To get ready for the example, we will delete
'fnstructions 86 and 70.
Display Shows
(lD:Data) Explanation
: LOG1
01:00
02:P86
O2:P7O
02:P00
:LOG1
OV4.3 SAMPLE PROGRAM 2
Our second example is more representative of
a data collection situation. This time the panel
temperature will be used as the reference
temperature for a type T (copper-constantan)
thermocouple (TC). Thermocouples measure
the temperature relative to their reference
junction temperature. To obtain the absolute
temperatu re, the refe rence j u nction temperatu re
must be known.
The 21X is shipped with a shorl thermocouple
wired to differentialchannel 5. The copper lead
is connected to the high input (H) and the
constantan lead is connected to the low input
(L). We'll read the sensor every 5 seconds, and
store one hour average temperatures along with
a daily maximum and minimum temperature
and the times at which they occur. The date
and time will also be stored with the data.
ov-l2
21X is in *0 Mode
Enter Program Table 1.
Jump to 2nd instruction in table; Instruction 86,
DO.
Delete Instruction 86. Second instruction is now
70.
Delete Instruction 70. Second instruction is now
vacant.
Return to *0 Mode
lnstruction 14 measures TC temperature with a
differential voltage measurement. The first
parameter is the number of times to repeat the
measurement. There is only one thermocouple,
so we enter a 1. lf there were several TCs.
could be wired to sequential input channels and
the number of TCs would be entered in
Parameter 1. The 21X would measure all of
TCs.
Parameter 2 is the full scale voltage input range
to use when making the measurement. Type T
TC signals are very small, approximately
4OuVPC difference in temperature between the
measurement and reference junction. lf we use
a range code of 1 (t5 mV full scale, slow
integration), the TC voltage will not exceed the
input range as long as the measurement
junction is within 125oC of the panel
temperature.
Key
2A
*1
#D
#D
*0