IC697ALG440
This Datasheet for the
IC697ALG440
Analog input Expander, Current, 16 Channels.
http://www.cimtecautomation.com/parts/p-14750-ic697alg440.aspx
Provides the wiring diagrams and installation guidelines for this GE Series 90-30
module.
For further information, please contact Cimtec Technical Support at
1-866-599-6507
[email protected]
1
Analog Modules
57
Base Converter Module - IC697ALG230, Current Expander Module - IC697ALG440
Voltage Expander Module - IC697ALG441
GFK-0385F
August 1997
Analog Modules
Analog Input System, High Level, 16 Channels
Analog Input System, High Level, 16 Channels Base Converter Module - IC697ALG230, Current Expander Module IC697ALG440
Voltage Expander Module - IC697ALG441
datasheet GFK-0385F
Features
D
Complete Analog subsystem includes Base Converter
and Expander modules
D
Base Converter module has eight differential inputs
individually configurable for voltage or current
D
Accepts unipolar or bipolar Analog Inputs up to " 10
volts full scale
D
D
Accepts 4 to 20 milliamp current loop signals
D
D
D
D
D
Individual user scaling on each input channel on Base
Converter module; scaling on a per module basis for
Expander modules
a44001
OK
EXP ACTIVE
OK
EXP ACTIVE
INPUT
ANALOG
INPUT
ANALOG
HIGH LEVEL
1
2
3
CHANNEL 1
+
5
2
6
Fast update rate for Base Converter module
Voltage and current Expander modules, each with 16
inputs, provides for additional inputs at a lower cost
per point
Complete subsystem can accept up to 120 inputs
1
4
7
CHANNEL 2
GND
9
10
11
+
3
12
13
4
CHANNEL 3
14
15
No jumpers or DIP switches to configure
Easy configuration with MS-DOSror Windowsr
programming software configuration function.
GND
8
GND
GND
16
17
CHANNEL 4
18
19
+
5
20
21
6
22
CHANNEL 5
23
GND
GND
24
25
26
27
CHANNEL 6
+
7
28
29
8
30
31
CHANNEL 7
GND
COM
GND
32
33
COM
35
GND
34
36
CHANNEL 8
3
4
37
E
E
38
39
COM
1
2
40
MODULE IC697ALG230
LABEL 44A726758–017R02
SLOT
Figure 1. Base Converter Module
r IBM and PS/2 are registered trademarks of International Business Machines Corporation.
r MS-DOS, Windows, Windows 95, and Windows NT are registered trademarks of Microsoft Corporation.
t
Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
57-1
Analog Modules
2
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
Functions
The High Level Analog Input subsystem for the Programmable Logic Controller (PLC) accepts analog inputs of up to Ç 10 volts full scale, or 4 to 20 milliamp
current loop signals. These inputs are converted to
digital form for use by the CPU or other controllers
accessing analog inputs via the VME backplane.
Converted data is presented as 2’s complement (sign
+ 15 bits). The basic converter is 14 bits resolution (1
part in 16384); an oversampling and averaging technique further enhances this resolution. Inputs are
protected against transient and steady-state overvoltage conditions.
Analog inputs use %AI references in the programmable controller. A maximum of 8K words of %AI
memory is currently available in the programmable
controller. Each input channel uses one word (16 bits)
of %AI memory.
Field wiring is made to a removable terminal board
and the module is mechanically keyed to ensure correct replacement with a similar module type in the
field. I/O references are user configurable without the
use of jumpers or DIP switches on the module.
Configuration is done using the configuration function of the MS-DOSr or Windowsrprogramming software running on Windowsr 95 or Windows NTr over
Ethernet TCP/IP or through the SNP port. The Programming Software configuration function is installed
on the programming device. The programming device can be an IBMr XT, AT,PS/2r or compatible Personal Computer.
a44002
OK
EXPANDER
ANALOG (V)
HIGH LEVEL
CHANNEL 1
CHANNEL 2
CHANNEL 3
CHANNEL 4
CHANNEL 5
CHANNEL 6
CHANNEL 7
CHANNEL 8
CHANNEL 9
CHANNEL 10
CHANNEL 11
CHANNEL 12
CHANNEL 13
CHANNEL 14
CHANNEL 15
CHANNEL 16
SLOT
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎÎ
Î
OK
EXPANDER
ANALOG ( )
+
1
+
1
2
3
2
4
+
5
+
3
6
4
7
8
+
9
+
5
10
11
6
12
+
13
+
7
14
8
15
16
+
17
+
9
18
19
10
20
21
+
12
+
11
22
23
24
25
+
+
13
26
27
14
28
29
+
+
15
30
31
16
32
GND
33
GND
35
GND
34
36
3
37
E
4
E
38
39
COM
1
2
40
MODULE IC697ALG441
LABEL 44A726758–019R02
Figure 2. Expander Module
57-2
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Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
Analog Modules
3
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
High Level Analog Input System Modules
Three module types are included in the High Level
Analog Input subsystem: a Base Converter module, a
Current Expander module, and a Voltage Expander
module. A typical subsystem will use a Base Converter module and (if required) one or more expander
modules.
D Expander Modules
Up to seven Expander modules can be daisychained off the Base Converter module to increase the number of inputs of the total subsystem up to a maximum of 120.
D Base Converter module - catalog number
The Base Converter module accepts any mix of
the two Expander module types.
IC697ALG230
A common user scaling factor applies to all inputs on each Expander module, however each
Expander module may be individually scaled as
required.
This module has eight differential inputs and
an expansion port. Each input can be individually configured for either voltage or current.
Each of the input channels also has individual
user scaling.
D Current Input Expander module - catalog number
IC697ALG440
On-board load resistors are included for normal
input current ranges up to Ç 40 mA. If other
current ranges or different resolution is required, external resistors may be used.
The Current Expander module has 16 current
inputs each accepting up to Ç 20 mA.
D Voltage Input Expander module - catalog number
IC697ALG441
Standard system configurations for Ç 10 volts
and 4 to 20 mA are available. These, and other
lower input ranges, can be scaled to engineering units with the user scaling feature.
The Voltage Expander module has 16 differential voltage inputs each accepting up to Ç 10V
signals.
a44003g
PROGRAMMABLE CONTROLLER
P
S
Î
C
P
U
o
r
B
R
M
B
A
S
E
E
X
P
E
X
P
E
X
P
(I)
(I)
(V)
E
X
P
E
X
P
(V) (I)
E
X
P
E
X
P
(V)
(I)
C
O
N
V
E
R
T
E
R
Î
UP TO 7 EXPANDER MODULES PER SUBSYSTEM
Figure 3. Example of High Level Analog Input System
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Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
57-3
Analog Modules
4
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
System Operation
The following illustration is a block diagram of the
High Level Analog Input system followed by an example of typical input connections.
a44004
A/D
LOW
PASS
FILTER
IN 1
BASE
CONVERTER
INPUTS
CONTROL
LOW
PASS
FILTER
IN 8
OPTO-ISOLATION
MUX
LOW
PASS
FILTER
IN 1
PLC BACKPLANE
AMP
EXPANDER
INPUTS
CONTROL
LOW
PASS
FILTER
IN 16
EXPANDER
CHANNEL
SIGNAL
MUX
EXPANDER
CHANNEL
ADDRESS
Figure 4. High Level Analog Input System Block Diagram
JMP
IN
Î
Î
Î
a44005
* * 250
10K
* 250
HIGH
IMPEDANCE
.1 µ fd
IN
10K
MUX
COM
(ANLGCOM)
GND
10K
* CURRENT EXPANDER ONLY
SIGNAL
COMMON
TO
EXPANDER
MODULES
** BASE CURRENT ONLY
Figure 5. Example of Input Connections
57-4
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Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
Analog Modules
5
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
addition to the information in this data sheet, circuit
wiring diagrams are printed on the inside surface of
the label inserted in each module’s hinged door.
User Wiring Connections
The following illustration shows the wiring assignments for the screw terminals on the terminal board
of the Base Converter and Expander modules. In
INPUT
ANALOG
EXPANDER
ANALOG ( )
1
3
+
7
GND
4
GND
11
13
15
8
GND
19
23
32
COM
34
35
3
4
2
40
MODULE IC697ALG230
BASE CONVERTER
GND
35
GND
36
3
4
2
40
37
E
1
E
38
39
COM
33
34
GND
37
E
1
E
39
COM
GND
36
38
31
GND
34
GND
37
E
16
+
15
30
32
33
GND
35
4
29
+
31
COM
36
3
+
32
33
27
14
15
30
16
GND
+
13
26
28
29
+
31
GND
25
+
27
29
23
+
28
30
+
11
22
12
13
26
14
7
28
8
21
+
24
25
+
27
+
+
11
23
25
19
10
24
26
9
18
20
22
12
GND
24
+
17
+
19
21
+
22
GND
+
9
20
21
6
15
16
18
10
5
20
7
14
8
17
+
+
13
+
15
17
+
+
7
16
18
11
12
14
16
5
10
6
13
+
+
9
+
12
14
GND
+
5
11
6
7
8
10
3
12
3
6
4
9
+
+
5
+
7
9
4
+
3
8
10
+
4
6
8
3
2
5
+
6
1
2
4
5
2
+
3
2
+
1
1
2
1
4
+
1
+
2
a44007
EXPANDER
ANALOG ( )
39
COM
1
E
38
2
40
MODULE IC697ALG440
MODULE IC697ALG441
CURRENT EXPANDER
VOLTAGE EXPANDER
JUMPER
CONNECTS AN INTERNAL 250 OHM LOAD FOR CURRENT INPUTS: LEAVE OFF FOR VOLTAGE
INPUTS (BASE CONVERTER ONLY).
GROUND (GND) IS CHASSIS GROUND.
COMMON (COM) IS ANALOG COMMON.
+ AND – SHOW POLARITY FOR DIFFERENTIAL INPUTS REFERENCED TO COM.
PINS 35 THROUGH 40 FORM THE ANALOG EXPANSION BUS.
Figure 6. Field Wiring Connections to I/O Terminal Boards (Base Converter and Expander Modules)
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Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
57-5
Analog Modules
6
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
Recommended Field Wiring Procedures
The following procedures are recommended when
connecting field wiring to the detachable terminal
board on an Analog Input Base Converter or Expander module. Module features referenced in the following procedures which are common to all IC697 I/O
modules are illustrated in the following figure.
a43855
JACKSCREW
HINGED
DOOR
TERMINAL
BOARD
CORD
TIE
ÎÎ
ÎÎ
CORD
TIE
CLEAT
ÎÎ
ÎÎ
JACKSCREW
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
Î
Î
ÎÎÎÎ
Î
Î
Î
Î
CORD
TIE
CLEAT
CORD
TIE
STRAP
CLEAT
Î
Î
Î
Î
STRAP
STRAP
Figure 7. I/O Module Features
1. Turn off power before removing or installing terminal boards. Open the hinged door on the module to access a jackscrew which holds the terminal
board securely in place. The detachable field wiring terminal board can now be removed from the
module by turning the jackscrew counter-clockwise until it is fully disengaged.
2. To remove the terminal board, grasp the top of the
terminal board and swing it outward.
Caution
Do not use the hinged door to remove the
terminal board. The hinged door could
be damaged if this is done.
57-6
3. The terminal board is designed to accept wire sizes
from AWG #22 (0.36 mm) through AWG #14 (2.10
mm). It is important that when using AWG #14
(2.10mm) wire for wiring all points, that a maximum insulation diameter of .135 inch (3.43mm)
not be exceeded. To ensure proper connection,
two wires may be terminated on any one terminal
only if both wires are the same size.
4. The terminal board is designed to accept a maximum of (40) AWG #14 (2.10mm) wires. If AWG
#14 (2.10mm) wires are to be used, then wire
markers should be placed at least 8 inches (203
mm) from termination end to provide sufficient
space for the hinged door to close.
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Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
Analog Modules
7
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
Î
ÎÎ
ÎÎÎ
ÎÎ
ÎÎÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎ
ÎÎÎÎÎ
ÎÎÎ
ÎÎ
Î
ÎÎÎ
ÎÎ
ÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
Î
ÎÎ
Î
ÎÎ
ÎÎÎ
JACKSCREW
a43747
ÎÎÎ
ÎÎ
ÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎÎÎÎ
ÎÎ
ÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
DO NOT
PULL
ON DOOR
WIRE BUNDLE CABLE TIE CLEAT
Figure 8. Removal of I/O Terminal Board
5. After completing connections to all modules in a
rack, the wire bundle must be secured. To ensure
that the wire bundle is secured properly, it is recommended that a cable tie be wrapped around the
wire bundle and tightly secured through the cable
tie cleat located at the lower right corner of the
terminal board. For extremely large wire bundles,
additional cable ties should be used.
6. A door label insert is included with each module to
indicate circuit wiring information and provide
space to record user circuit wiring identification.
A slot is provided on the hinged door to allow for
insertion of this label. If the label is difficult to insert, crease the scored edge before insertion. The
outside label has a color coded stripe to allow
quick identification of the module voltage type
(blue: low voltage; red: high voltage).
7. After field wiring is completed, the terminal board
should be securely fastened to the rack by inserting the terminal board strap (attached to each
module) into the small rectangular slots in the bottom card guide grill on the rack. This strap not
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Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
only secures the terminal board to the rack, it also
provides a way of identifying the wired terminal
board with its correct mating rack slot location.
8. For adequate module ventilation, it is recommended that at least a 5 inch (127mm) clearance be
allowed above and below the rack grill. Wire
bundles should not obstruct the rack grill work.
Removing an I/O Module
The instructions below should be followed when removing an I/O module from its slot in a rack.
D Grasp the board firmly at the top and bottom of
the board cover with your thumbs on the front of
the cover and your fingers on the plastic clips on
the back of the cover.
D Squeeze the rack clips on the back of the cover
with your fingers to disengage the clip from the
rack rail and pull the board firmly to remove it
from the backplane connector.
D Slide the board along the card guide and remove it
from the rack.
57-7
Analog Modules
8
GFK-0385F
August 1997
Field Wiring Considerations
Connections to Base Converter and Expander modules from user devices are made to screw terminals on
the removable 40-terminal connector block mounted
on the front of each module. All field connections to
the inputs should be wired to the I/O terminal board
using a good grade of twisted, shielded instrumentation cable.
The internal resistor for 20 mA current inputs on the
Base Converter module is connected by jumpering
the upper two terminals on the group for the desired
channel, for example, JMP 0 to IN 0+ (refer to Figure
5 for signal names for each group).
Ground connections, (GND), on the terminal board
are provided for connecting shields. This ground connection is made directly to the rack, resulting in superior rejection of noise caused by any shield drain currents. Actual selection of ground location may be
influenced by system power and ground considerations. However, best operation will be obtained
when system ground is physically close to the rack
containing the analog circuits. Normally, the shield is
grounded at only one end.
Analog Input System, High Level, 16 Channels
arate analog common, or if the system is grounded, a
separate (from power devices) quiet ground. It could
be limited in scope to only the base converter and
associated expander COM. The differential configuration reduces errors from DC or low frequency AC supply and ground currents by separating the signal
wires from the common which may carry these currents. High frequency and higher voltage spike noise
is reduced by filters at the module inputs.
Do not confuse these inputs with Isolated type inputs,
which have no reference to any common. Sources that
have high impedance isolation must not be left floating
since the high input impedance of the module may
allow common mode voltage to drift out of range.
This may cause noisy or erroneous data, possibly affecting other channels as well. The differential input
allows freedom with respect to location where the
signal is referenced to the supply. The differential input can be converted to single ended (referenced to
COM), by connecting IN(–) directly to COM at the
module terminal. Typical connections for differential
inputs are shown in the two figures on the next page.
The best advantage of the superior noise rejection of
the differential inputs is obtained by running both
input lines to the signal source (as shown in Figure 9),
regardless of where ground reference or power supply commons are located.
Current inputs require a connection between JMP and
IN+ terminals to connect the internal shunt. This converts the 4 - 20 MA current to a 1 to 5 volt signal.
Jumpers are arranged on adjacent terminals to permit
use of commercially available jumper strips, which
allows for both jumper and wire in the same terminal.
Isolated current sources should be referenced to COM
by jumpering IN– to COM. Non isolated loops usually should have the return side of the loop supply connected to the analog common. Usually one supply
sources several loops, and it is preferable to locate the
supply near the analog input. The IN(–) side is returned to COM, either at the module, or wired back
to the common side of the loop supply, if the supply is
remote.
Inputs are differential. This means the input converted
value is the result of the difference between the positive input (+) and the negative input (–), each with
respect to COM. Either input can be either polarity
with respect to COM. The voltage between the inputs is called Normal Mode, while the voltage between
inputs and COM is called Common Mode. All input
signals should have a reference to a system common
to ensure that common mode voltages remain within
the input range of the module. This is normally a sep-
Field wiring should be shielded wire. Twisted pair,
triad (3 wire twisted) or multiple pair cable may be
used. Shields are usually grounded at the end nearest
where analog signal ground or common is established. Ground at the module if in doubt. Ground
terminals are provided for convenience on the module. Variations in data caused by high noise environments are often reduced by additional AC bypass of
the shield to ground with a .01 to .1 microfarad capacitor at the ungrounded end.
For additional system grounding information refer to the
discussion on system grounding in chapter 3 of the applicable Programmable Controller Installation Manual.
The module provides electrical isolation of externally
generated noise between the input field wiring and
the backplane through use of optical isolation.
57-8
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Analog Modules
9
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
In extreme noise environments, the shield can be
grounded at both ends, provided the shield is not
used to carry any analog signal or analog supply voltages. For noise or surges conducted from sources outside the control enclosure, you should consider terminating the shield at the incoming location of the
enclosure, either using a ground bar or a collar clamp
which grounds the shield directly to the metallic enclosure. This gives a much lower ground impedance
than possible on the module. The shield is continued
up to the module but does not require connection at
the module.
Voltage Input Examples
{I}
Voltage
Source
(Grounded
at source)
{I}
+
IN
–
+
V
–
+
+
Voltage
Source V
–
(Isolated))
IN
–
GND
GND
{I}
{I}
+
IN
–
+
IN
–
GND
Bridge
Circuit
COM
Slide
wire
GND
ALG230
System analog common or low noise (quiet) Ground
(optional)
Local
System
Ground
Current Input Examples
{I}
I
{I}
+
IN
–
2 wire
loop powered
GND
+
IN
–
I
GND
Isolated
Source
{I}
+
– Out
{I}
+
IN
–
I
+
IN
–
I
GND
GND
3 wire source
Loop
Supply
Multiple
drops
COM
ALG230
System analog common or low noise (quiet) Ground
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Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
250 ohms max
(optional)
Local
System
Ground
57-9
Analog Modules
10
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
ANLGCOM is the reference level for all signal inputs.
For normal operation when the input signals are referenced to ground, the ANLGCOM terminal may be
left open since it is internally connected to ground
through an RC circuit as shown in Figure 9. Note that
all input signals must be within Ç 13 volts of ANLGCOM to obtain specified performances.
IN
15V
a44008g
IN
V
15V
ON-BOARD
POWER
SUPPLY
INPUT FROM
BACKPLANE
OUTPUT
ANLGCOM
COMMON
60V
TO
EARTH GROUND
ON PLC RACK
GROUND
Figure 9. ANLGCOM Connection to Ground
Note
For applications in which the input signals are
not referenced to ground, an offset voltage
may be introduced between ANLGCOM and
GND as shown in Figure 9 to ensure that the
input is within the common mode limits of
Ç 13 volts. Note that all inputs for a single
Base Converter/Expander subsystem are referenced to ANLGCOM on the Base unit. The
maximum offset voltage for ANLGCOM is Ç
60 VDC with respect to earth ground.
If any of the inputs appear to be fluctuating in values,
ensure that all terminal pairs are connected to COM
or GND.
57-10
Expansion Bus
The bottom six terminals (35 through 40) on the terminal board on the Base Converter and Expander
modules make up an expansion bus for connecting
input Expander modules to the Base Converter module. An analog multiplexer on the Expander module
acts as a switching circuit to connect analog inputs,
one at a time, to the A/D (Analog to Digital) converter
on the Base Converter module.
Input Sampling Techniques
The objective of the input sampling technique for the
analog subsystem is to provide 8 input channels on
the base module that have a fast (approximately 3 ms)
update rate and additional expander channels that are
updated less frequently, but have a lower cost per
channel.
Operation is such that the base module initially updates all eight channels plus one expander channel.
On each successive scan all eight channels of the base
converter are again updated - plus the next expander
channel in sequence. After 16 analog input scans all 16
channels of the first expander have been sampled; on
the next scan, all eight base converter channels plus
the first channel of the next Expander module are
scanned.
This sampling technique continues until all available
expander channels (16 x number of Expander modules) have been scanned, at which time the sequence
starts over. The number of analog scans required to
include sampling of all expander channels is equal to
the total number of Expander modules x 16 (16 channels per Expander module) in the system.
With no Expander modules present, each base converter channel is updated once every 2.4 milliseconds.
With one or more Expander modules present, this
update time increases to 2.8 milliseconds.
Each expander channel is updated every 2.8 x N ms
(where N = total number of Expander channels present). Note that the scan sequence is free running and
it cannot be synchronized with any external event.
Also note that all inputs of an Expander module will be
scanned even if they are not being used.
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Analog Modules
11
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August 1997
Analog Input System, High Level, 16 Channels
Table 1. Analog Input Channel Update Times
Number of Expander
Modules
Base Channel
Update Rate (ms)
Expander Channel
Update Rate (ms)
0
1
2
3
4
5
6
7
2.4
2.8
2.8
2.8
2.8
2.8
2.8
2.8
–
45
90
134
179
224
269
314
three-conductor shielded cable can be used, with the
third wire making the EXPSHLD connection, and the
shield connection to GND.
Connecting the Expander Bus
Terminals 36 and 38 connect the selected analog expansion signal to the Base Converter module. Terminal 40
provides the analog common connection between modules. These terminals should be bussed in parallel with
twisted, shielded wire, observing polarity on terminals
36 and 38. The shield must be connected at terminal 40
at both ends of all links between modules in order to
connect COM of all boards together. Alternately, a
NOTE:
Terminals 37 and 39 are the expander differential data
bus. This is a serial communications port which allows
the base converter processor to control the expanders.
They must be connected with twisted pair cable, observing polarity. Shielding is optional; if used, connect
the shield to GROUND at terminal 35.
SHIELDS MUST BE CONNECTED AT EACH END TO TB40
Î
BASE
CONVERTER
35
36
37
38
39
40
Î
Î
a44009
EXPANDER 1
Î
35
36
37
38
39
40
Î
EXPANDER 2
Î
Î
35
36
37
38
39
40
Î
Figure 10. Expander Bus Connections
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57-11
Analog Modules
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August 1997
Analog Input System, High Level, 16 Channels
Expander channel numbers are assigned by the system based on the physical location of the Expander
module relative to the base converter module. For
example, the Expander module in the slot to the immediate right of the base converter module is assigned channels 9 through 24, the next expander is
assigned channels 25 through 40, etc., as shown in the
following figure.
Module/R ack Configuration
A high level analog input system for the programmable controller can consist of any combination of
Base Converter modules and Expander modules up to
the I/O module capacity of the rack, or a maximum of
120 inputs for each Base Converter module.
Up to seven Expander modules may be interfaced to a
Base Converter module to attain the maximum of 120
inputs (7 Expander modules x 16 inputs = 112 + 8
inputs on Base Converter). Expander modules must be
physically located in the same rack as the Base Converter module, and must be installed in slots to the
right of the base converter module. These modules must
be adjacent to each other.
Expander modules should be located to the immediate right of the controlling Base Converter module,
with no empty slots or different module types located
between the Base Converter and Expander modules,
or between Expander modules.
PROGRAMMABLE CONTROLLER
P
S
Î
C
P
U
B
A
S
E
E
X
P
E
X
P
a44010g
E
X
P
Î
C
O
N
V
E
R
T
E
R
CHANNEL 41 THROUGH 56
CHANNEL 25 THROUGH 40
CHANNEL 9 THROUGH 24
CHANNEL 1 THROUGH 8
Figure 11. Example of Channel Number Assignments
Module Mechanical Keying
Each module includes a mechanical key that prevents
inadvertent substitution of one module type for
another in a given slot. The key fits a uniquely
shaped area on the board below the connector.
When the module is first installed, the key latches
onto the backplane center rail. When the module is
extracted, the key remains attached to the center rail,
thereby configuring the slot to accept only identical
module types.
57-12
If it is necessary to change the module location in the
rack after the key has been latched onto the center rail
of the rack, the key can be removed by pushing it upward to unhook the latch while pushing it off the rail.
It may then be reinserted into the rack in the desired
location.
Note that in an IC697CHS PLC rack only the power
supply can be placed in the leftmost rack position, and
slot 1 (adjacent to the power supply) must always contain a CPU (in rack 0 - the CPU rack), or a Bus Receiver
Module or Remote I/O Scanner (in expansion racks).
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Analog Input System, High Level, 16 Channels
Configurable Functions
D
The type selected (voltage or current) for each Expander module
You can configure certain functions through the MSDOS or Windows software configurator function using the programming device. These functions include input ranges, user scaling, and the alarm
comparator function. These functions and their definitions are listed in Table 2.
D
The number of channels used for all present Expander
modules
D
The high and low alarm settings for each main input
channel
Module Configuration Data
D
The input type (voltage or current) for each main input channel
When power is initially applied to the analog modules
the CPU will be updated, through backplane and
module software, with the following configuration
data:
D
CPU alarm interrupt, whether enabled or disabled on
a per channel basis (Base Converter module only)
D
CPU fault reporting, whether enabled or disabled on a
per channel basis for Base Converter module and per
board for Expander module
D
Number of main (Base Converter module) input channels used
D
Number of Expander modules present and their slot
location relative to the Base Converter module
After the CPU has been updated with this initial configuration data, the CPU provides the following module configuration data;
Each of the input channel values is checked for overrange, underrange, and open wire if configured for 4,
20 mA.
Table 2. Configurable Features for the Base Converter Module
Feature
Channel or Module
Selections
Default Setting
–10V, +10V
0, +10
Voltage/Current
Channel
–5V, +5V
–10V, +10V
0, +5V
4, 20 mA
t
Report Faults
Channel
Enabled/Disabled
Enabled
Scaling Points
Channel
User Value
" 32767 µA
+32000, –32000 µA
mV or mA
" 10000 mV
+10000 mV, –10000 mV
Enabled/Disabled
Disabled
Low
" 32767
–32767
High
" 32767
+32767
Report Alarms
Channel
Alarm Values
Channel
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Analog Modules
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Analog Input System, High Level, 16 Channels
Features of the Voltage Expander module that can be set-up during configuration are listed below.
Table 3. Configurable Features for the Voltage Expander Module
Feature
Channel or Module
Selections
Default Setting
–10V, +10V
0, +10
Voltage
Module
–5V, +5V
–10V, +10V
0, +5V
Report Faults
Module
Enabled/Disabled
Enabled
Scaling Points
Module
User Value
" 32767
+32000, –32000
mV
" 32767
+10000 mV, –10000 mV
Features of the Current Expander module that can be set-up during configuration are listed below.
Table 4. Configurable Features for the Current Expander Module
Feature
Channel or Module
Selections
Default Setting
Current
Module
4, 20 mA
4, 20 mA
Report Faults
Module
Enabled/Disabled
Enabled
Scaling Points
Module
User Value
" 32767
+32000, 0
mA
" 32767
+20000 mA, 4000 mA
Note
For detailed information on using the configuration function refer to the Programming
Software User’s Manual.
Input Ranges
The Base Converter input type (voltage or current)
can be individually programmed for each input point.
The range selected should match the input signal.
Current inputs require the use of the built-in or a user supplied external burden resistor. The Expander input
points are all the same on a module, either voltage or
current, determined by the module type.
57-14
User Scaling
The scaling feature allows you to define any linear
relationship between the sensed input voltage or
current and the value in engineering units that is
returned to the PLC. The default configuration, as
shown in Figure 12, provides values of –32000 to
+ 32000 corresponding to a voltage input range of
– 10 to +10 volts. If a channel (or Expander module) is configured for current, default scaling is 0 to
32000 for an input current range of 4 to 20 mA (see
Figure 13).
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August 1997
Analog Input System, High Level, 16 Channels
a44011
POINT
32000, 10000
INPUT
VOLTAGE
10000MV
32000
5000MV
30000
POINT
(16000,5000)
10000
0
10000
30000
USER
SCALING
32000
5000MV
10000MV
POINT
32000, 10000
Figure 12. User Scaling for Voltage Input
Scaling can be configured on a per channel basis for
the Base Converter module and on a per module
basis for Expander modules. Scaling is set by entering the desired voltage or current input value and
the corresponding engineering units for each of two
points. Engineering units are a 16-bit signed value
(– 32768 to +32767).
Note
Scaling to engineering units does not increase the resolution of the value, but does
transform it into more convenient units.
Scaling can be used to compensate for differences between actual and theoretical values due to inaccuracies encountered in field
devices.
When configuring scale factors, 0 mV or 0 mA must
correspond to an engineering units number between
+32767 and –32767.
INPUT
CURRENT
POINT 1
32000, 20000
a44012
20000 MA
(16000, 12000)
16000 MA
12000 MA
8000 MA
30000
POINT 2
(0, 4000)
4000 MA
10000
0
8000
10000
4000 MA
30000
USER
SCALING
8000 MA
12000 MA
16000 MA
20000 MA
Figure 13. User Scaling for Current Input
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Analog Modules
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Analog Input System, High Level, 16 Channels
Using Data Commands to Modify
Configuration
Communications Request
Function Block Format
The Data Command provides a mechanism which
allows you to modify some of the diagnostic configuration parameters of the Analog Input Base Converter
Module from ladder logic. The Data Command uses
the COMMREQ function block and a small block of
parameters to update certain configuration parameters on the fly.
The ladder logic representation of the COMMREQ
function block is as follows:
Sending Data Commands Using the
COMMREQ Function
The PLC ladder program sends a Data Command using the COMMREQ (Communication Request) function. The COMMREQ requires that all its command
data be placed in the correct order in the CPU
memory before it is executed. It should then be
executed by a by a one-shot to prevent sending the
data to the module multiple times. Successive
COMMREQs must be separated by at least 1 millisecond to guarantee correct processing.
A description of the COMMREQ function and its
command block data follows, along with a ladder example which uses registers %R0001 to %R0009 for the
COMMREQ command block. Refer to the applicable
Programmable Controller Reference Manual for additional
specific information on COMMREQs.
COMMREQ Function Block Description
%Q0200
+——————+
—] [———(enable)+ COMM_+—(ok)—
| REQ |
%Q0201
%R0001——+IN FT+————––––——————( )——
|
|
CONST ——+ SYSID|
0107
|
|
|
|
CONST ——+ TASK |
00001
|
|
+——————+
The Communications Request function block has four
inputs and two outputs. The first input is an enable
input. Generally a one-shot coil is used to enable the
COMMREQ function. This prevents multiple messages from being sent. The second input (IN) is the
starting location of the COMMREQ command block.
The SYSID input is used to indicate which rack and
slot to send the message to (physical location of Analog module). The last input (TASK) is set to the channel number to be configured. In the above example,
channel 1 of rack 1, slot 7 will be configured and the
COMMREQ command block starts at Register 0001.
Power is always passed to the ok output. The fault
output (FT) is enabled if the COMMREQ fails.
The Communications Request (COMMREQ) function
is a conditionally executed function that
communicates a particular request, through the
ladder logic program, to the Analog module.
57-16
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Analog Input System, High Level, 16 Channels
Command Block
The command block for Data Commands is made
up of nine words (all values in hexadecimal unless
otherwise indicated). Use the block move
command to move these values to the Register
tables (refer to the applicable Programmable
Controller Reference Manual, for information on using
the block move function).
Table 5. Command Block for Data Commands
Location
Data
Description
%R0001
0003
Length of data is three words
%R0002
0000
Not used (Always zero)
%R0003
0000
Not used
%R0004
0000
Not used
%R0005
0000
Not used
%R0006
0000
Not used
%R0007
nnnn
Data Command - Command Word - Word 0
%R0008
nnnn
Data Command - Command Word - Word 1
%R0009
nnnn
Data Command - Command Word - Word 2
Analog Input Data Command Parameters
The Data Command can be used to change the configuration of Fault Reporting, Alarm Interrupts, and Alarm
Thresholds for each channel of the Base Converter.
Each Data Command reconfigures all of the parameters
for the specified channel using the new data.
Table 6. Analog Input Data Command Parameters
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Location
Description
Command Word 0
Configuration Word
Data
Bit 8:
Bit 13:
Command Word 1
HighAlarm Threshold
Range +/– 32767 Engineering Units
Command Word 2
Low Alarm Threshold
Range +/– 32767 Engineering Units
Bits in the configuration word are numbered with bit
1 being the least significant bit. Note that changing
the configuration of the Alarm Interrupt will have no
t
0 - Fault Report Enable
1 - Fault Report Disable
0 - Alarm Interrupt Disable
1 - Alarm Interrupt Enable
Series 90 -70 Programmable Controller Data Sheet Manual
GFK-0600F
effect unless the channel has Alarm Interrupts enabled in the initial configuration folder created using
the IC641 configuration software.
57-17
Analog Modules
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August 1997
Example - Sending Data Commands
An example of ladder logic for sending a data command to an Analog Input module using COMMREQ
function blocks is shown below. In this example, the
COMMREQ command block is located in registers
%R0001 through %R0009. The command to send the
data is initiated by the conditional input %I0289
which sets output %Q0200 for one sweep. The Analog Input module is located in Rack 1, slot 7 (first expansion rack). This command will disable fault re-
Analog Input System, High Level, 16 Channels
porting, enable alarm interrupts, and set the high and
low alarm thresholds to +20000 and –20000, respectively.
If the COMMREQ command data is formatted incorrectly, or has an invalid command, the Analog Input
module will set the Error Status %I bit, and return an
error code in Module Status Code %AI word.
Note that the comments within /* . . . . */ have been included for information purposes only. They are not generated by the programming software.
|
|%I0289
%Q0200
+–—] [————————————————————————————————————————————————————————————(P)——
|
|%I0290
%Q0201
+——] [————————————————————————————————————————————————————————————(P)——
|
|%Q0200 +—————+
+——] [———+BLKMV+—
/* Move Command block into Registers 1—7 */
|
| WORD|
|
|
|
| CONST —+IN1 Q+—%R0001 /* Command block data starts at %R0001
*/
| 0003 |
|
/* Command data length is 3 words
*/
|
|
|
/*
| CONST —+IN2 |
| 0000 |
|
/* Not used (always 0000)
*/
|
|
|
| CONST —+IN3 |
| 0000 |
|
/* Not used (always 0000)
*/
|
|
|
| CONST —+IN4 |
| 0000 |
|
/* Not used (always 0000)
*/
|
|
|
| CONST —+IN5 |
| 0000 |
|
/* Not used (always 0000)
*/
|
|
|
| CONST —+IN6 |
| 0000 |
|
/* Not used (always 0000)
*/
|
|
|
| CONST —+IN7 |
| 1080 +—————+
/* First word (Command Word)
*/
|
/* In this case, disable fault reporting */
|
/* and enable alarm interrupts
*/
57-18
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Analog Input System, High Level, 16 Channels
19
GFK-0385F
August 1997
|
|
|%Q0200 +—————+
+——] [———+BLKMV+—
/* Move data into registers 8 through 14 */
|
|WORD |
|
|
|
| CONST —+IN1 Q+—%R0008
| 4E20 |
|
/* Register 8 sets the High Alarm
*/
|
|
|
/* to 20000 (Hexadecimal 4E20)
*/
| CONST —+IN2 |
| B1E0 |
|
/* Register 9 sets the Low Alarm
*/
|
|
|
/* to –20000 (Hexadecimal B1E0)
*/
| CONST —+IN3 |
| 0000 |
|
/* Remaining registers are not used
*/
|
|
|
| CONST —+IN4 |
| 0000 |
|
|
|
|
| CONST —+IN5 |
| 0000 |
|
|
|
|
| CONST —+IN6 |
| 0000 |
|
|
|
|
| CONST —+IN7 |
| 0000 +—————+
|
|
|
|
|
|
/* Now call the COMMREQ to send the message */
|
|%Q0200
+—————+
+——] [————————+COMM_+
|
| REQ |
/* COMMREQ will set output %T0051 if failure */
|
|
|
/* detected when sending message.
%T0051 */
|
%R0001 —+IN FT+———————————————————————————————————————————( )——
|
|
|
/* Command block data starts in R0001
*/
|
|
|
|
CONST —+SYSID|
/* Analog Input Module is in rack 1, slot 7 */
|
0107 |
|
|
|
|
|
CONST —+TASK |
/* Task is set to the channel to be
*/
|
00000001 +—————+
/* configured, in this case channel 1
*/
|
|
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Analog Input System, High Level, 16 Channels
Diagnostics
for Expander module configuration data. The LED is
turned on when the Expander module is configured
Diagnostic capabilities for the analog high level input
system include:
The LED is turned off when a board failure has been
detected.
D
LEDs on modules for system status indication
D
Monitoring health of Base Converter and Expander
modules
D
Detection of configuration errors
D
Monitoring communication between Base Converter
and Expander modules
D
Overrange and underrange detection
Alarm Comparator Function
D
Open wire detection
D
Monitoring of high and low alarm limits
D
Expander channel not responding
The Alarm Comparator Function provides a mechanism to initiate special processing when an input goes
outside a specified operating range. Alarm Thresholds can be set anywhere over the dynamic range of
the signal. Typically, they are set at levels beyond
which the input should not operate or levels beyond
which alternate processing is required. They can also
be set beyond the dynamic range of the signal, ensuring that they will never be activated. The desired operating range is defined by user configurable high and
low thresholds. The alarms do not affect operation of
the module or change the scaled input value. The
Alarm Comparator function is available only on the
Base Converter module.
Module LEDs
There are two LEDs on the Base Converter module
and one LED on each of the Expander modules.
Base Converter Module
The Base Converter module has two LEDs. The upper LED, labeled BOARD OK flashes when the module has powered-up, passed its diagnostic tests, and is
waiting for configuration data from the CPU. After
receiving configuration data, the Board OK LED is
turned on if the data from the CPU is OK; it is turned
off if there is a configuration error.
The lower LED, labeled PORT OK, turns on when
communication is established with one or more Expander modules, and the expansion bus is operating
properly. Once the system is up and operating, this
LED is turned on when any of the configured expansion channels are responding. When none of the
configured expansion channels are responding, the
PORT OK LED is turned off
Expander Modules
There is one LED on an Expander module. This LED
flashes when the Base Converter module is waiting
57-20
Analog Input Diagnostics
Analog input diagnostics, including the Alarm
Comparator Function and I/O fault reporting are described below
Alarm Contacts
When the scaled input value goes outside either of
the configured thresholds, the appropriate high
(–[HIALR]–) or low (–[LOALR]–) alarm contact for
the channel is energized. One alarm is generated each
time an alarm threshold is crossed. The IC697 CPU
supports one –[HIALR]– and one –[LOALR]– contact pair per channel of the Base Converter module.
Alarm Interrupts
In addition, either alarm will also generate a triggered
ladder interrupt, if enabled in the channel configuration. The IC697 CPU supports a separate triggered
interrupt block for each input channel. When an
alarm interrupt occurs, the CPU updates the data for
that channel before activating the interrupt block.
Within the interrupt block, the logic can determine
which alarm occurred by examining the input data.
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Analog Input System, High Level, 16 Channels
Caution
An I/O interrupt can interrupt execution of
any program block, including the _Main
block. Therefore, unexpected results can
occur if the interrupt block and the program block access the same data. When it
is necessary for a program block and an interrupt block to access the same data, a
SVCREQ #17 can be used to temporarily
block the interrupt from executing when
the shared data is being accessed.
reported again until the fault condition is removed
and then occurs again.
Fault Contacts
Any combination of the following faults on a channel
will cause the corresponding fault contact to be energized. The IC697 CPU supports one –[FAULT]– and
–[NOFL T]– contact pair per input channel on both
Base Converter and Expander Modules.
Use of fault contacts requires that Point Faults be enabled in the CPU, as described in the applicable Programmable Controller Reference Manual.
Base Converter Faults
The execution of a block triggered from an interrupt
supersedes the execution of the normal program sequence. Execution of the normal program is suspended, and only resumed after the interrupt block
completes.
Alarm Configuration
Each Base Converter channel can be configured to
have a high and a low threshold value. Maximum
values are " 32767. The high threshold must be greater than the low threshold. Threshold limits are based
on circuit scaling. If scaling is changed, review and
readjust the Alarm Thresholds if necessary.
Note that an alarm threshold of " 32767 disables the
corresponding alarm, thus it is possible to have only a
high or low alarm. By default, the high and low alarm
thresholds are set to + and – 32767, respectively.
The alarm thresholds can be changed dynamically
using the Diagnostic Config Data Command, described elsewhere in this data sheet.
Use of alarm contacts requires that Point Faults be
enabled in the CPU, as described in the applicable
Programmable Controller Reference Manual.
I/O Fault Reporting
The IC697 Analog Input Modules support fault detection which is used to activate fault (–[FAULT]– /
–[NOFL T]–) ladder contacts in the PLC. In addition,
a corresponding fault message is logged in the PLC
I/OFault Table, unless fault reporting has been disabled in the channel configuration.
If fault reporting is enabled in the channel configuration, each fault condition is reported once, and is not
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Series 90 -70 Programmable Controller Data Sheet Manual
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Overrange
Input overrange occurs when either of the following
conditions is present:
1. The scaled input value is greater than 32767. Under this condition, the value is held at 32767.
2. The actual input voltage or current is greater than
the maximum Analog to Digital converter range
(approximately +10.2 volts or 40.8 mA).
Underrange
Input underrange occurs when either of the following
conditions is present:
1. The scaled input value is less than –32767. Under
this condition, the value is held at –32767.
2. The actual input voltage or current is less than the
minimum Analog to Digital converter range
(approximately –10.2 volts or –40.8 mA).
Open Wire
This diagnostic occurs when a channel is configured
for current mode (4–20 mA) operation and the input
current drops below 2mA.
Expander Faults
Expander Channel Not Responding
This fault is a result of a communications failure on
the expansion bus, or one or more expansion channels
are not responding due to a hardware failure.
Base Converter A/D Communications Fault
This error occurs when certain internal failures occur
on the Base Converter module. When this happens, a
57-21
Analog Modules
22
GFK-0385F
August 1997
Analog Input System, High Level, 16 Channels
fault message is sent to the CPU by way of a CPU interrupt. The module LEDs are turned off and the
module halts after sending the message to the CPU.
Analog Signal Terms
Configuration Errors
Single-Ended
The following configuration mismatch errors are detected by the Base Converter and reported to the CPU:
Single-ended circuits have the signal measured
relative to a common connection, usually the power
supply. Other analog I/O signals typically share this
common. Single-ended circuits require the fewest
terminal points, giving the highest density and lowest
price, but at the cost of more restrictive wiring and
errors due to voltage drops and currents in the
common connections. Single-ended circuit
connections are most similar to the wiring of discrete
modules.
D
User scaling error (user scaling offset calculation exceeds 16 bit signed data)
D
Expander module Configuration Error, Expander
module current or voltage range, or number of channels not as expected
Note
The system cannot determine if terminal
board resistors or jumpers for current inputs are properly installed. However, this
will often result in overrange faults when
current input signals are applied.
User Scaling Error
This error occurs when the user’s two scaling points
connected on a plot of engineering units versus mV or
mA do not cross the engineering unit’s X-axis between +32767 and –32767. In other words, 0 mV or 0
mA must correspond to an engineering units number
between +32767 and –32767. When this occurs a
fault is logged in the PLC I/O Fault Table. The module
LEDs are turned off and the module halts after reporting the fault to the CPU.
Expander Module Configuration Error
This error occurs when the Expander module configuration range or the number of channels per Expander
module is not as expected. On power-up the Base
Converter module scans the Expander modules connected to the expansion bus to determine their type.
If the actual configuration does not match the configured range or number of channels, an Expander module Configuration error is reported
57-22
This section explains some general terms relating to
measurements at analog I/O terminals.
Signal Common
The term signal common refers to a point in the signal
that may be connected to the corresponding points in
other signal loops. It may or may not be connected to
earth ground.
Differential
Differential signals are measured on two wires which
are separate, but not isolated from the power supply.
Differential inputs allow a greater degree of freedom
in wiring commons and grounds without affecting
accuracy. There is a limited voltage rating (see
Common Mode) between the signal level wires and
the power supply wires. This limitation also applies to
voltage differences among additional I/O on the same
supply.
Differential inputs usually come in groups sharing the
supply common tie point. Some voltage outputs may
have an external return or remote sense which allows the
load common or ground to be different than the
supply of the output module by a small voltage.
Current loop signals are less susceptible to differences
in voltage between circuit components (see
compliance). Differential inputs permit series inputs
with current loops, since the signal can be offset from
common. Do not confuse differential inputs with
isolated inputs; differential requires the common tie
point reference for all inputs of the group, usually
either ground or the supply common.
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Isolated
Isolated inputs are usually two-wire and are
dielectrically insulated from supplies and ground.
Sometimes additional connections are provided for
excitation of transducers such as RTDs, but these
signals are not shared with other I/O points. Isolated
modules allow high voltages to exist between I/O
devices and the PLC. Do not confuse isolated inputs
with the isolation between groups of analog circuits,
or isolation from other components of the system,
such as logic or power supplies.
Normal Mode
This is the actual signal across the signal wires of
differential or isolated I/O. This may also include
unwanted noise such as power line frequency pickup.
Common Mode
This is the voltage between the analog signal wires
and the common point of the power supply of a
differential signal, or to ground in the case of an
isolated signal. It is desirable that all common mode
signals are ignored by the circuit, but in practice there
is some error introduced in the data. This is specified
as Common Mode Rejection Ratio (CMRR), usually
expressed in decibels (db). Differential circuits also
have a maximum common mode voltage
specifications, usually stated as a maximum voltage
with respect to circuit common. Exceeding the
common mode voltage rating of differential signals
causes large errors in the data conversion and may
affect several points.
Unipolar
Unipolar signals or ranges do not change polarity
during normal operation; for example 0 to 10 volts, or
4mA to 20mA. Reversed connection to a unipolor
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input will produce minimum value and, if diagnostics
are available, underrange or open wire faults.
Bipolar
Bipolar signals can reverse polarity in operation.
Reversed signal connections to a bipolar input will
produce data of opposite sign.
Ground Loop
When a conductor is grounded in more than one
place, differences between grounds can induce
currents producing voltage drops in the wire. If the
conductor is also used to carry an analog signal, these
voltage drops produce an accuracy error or noisy
values. If a single point ground is used, the voltage
difference between locations may still appear in series
with the desired signal. This is overcome by using
differential or isolated inputs and running a separate
return from the remote source. This preserves the
integrity of the signal, and the ground voltages
appear as common mode voltage at the receiving end.
Current Loop
This is a standard analog interface defined by the
Instrument Society of America in ANSI/ISA-S50-1. The
signal level is 4mA to 20mA. Three types of signal
sources are defined, Types 2, 3, and 4. These
correspond to the number of wires used. The isolation
of the transmitter may impact the type of PLC input
required. When non-isolated inputs are used, isolation
may be provided by means of a current transducer
that has isolation between the current loop and/or
power supply. The Standard covers only isolated or
common (single-ended) inputs. Differential inputs
often used in PLCs, and connecting several current
loops together, as often occurs with PLCs, are not
covered well in the Standard, and often introduce
additional complication regarding location of
commons and grounds.
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Table 7. Analog Input Specifications [
Input Ranges:
Voltage: –10 volts to +10 volts
Current: 4 to 20 milliamps
Resolution:
Default Scaling (16 bit)
312.5 microvolts per LSB step on voltage
0.5 microamps per LSB step on 4 to 20 mA
No missing codes over 16 bits on voltage
No missing codes over 14 bits on current
NOTE: User scaling may introduce skipped codes in the lower 2 or 3 bits depending
upon the factors used.
Accuracy: Calibration
Factory set at full scale = 10 volts ±2 millivolts on Base Converter module.
Maximum errors at 25° C (77°F) are:
Base Converter Voltage, ±.01% of full scale, ±.02% of value
Base Converter Current, ±.05% of full scale, ±.1% of value
ExpanderVoltage, ±.03% of full value, ±.02% of value
ExpanderCurrent, ±.07% of full scale, ±.1% of value
Base Converter
Continuallyself-calibrates for zero and positive full scale (before user scaling)
values. Field calibration not normally required; there is no zero adjustment. A
trimpot on the Base Converter adjusts full scale value at 10V input. For critical
applications this can be reset to compensate for ageing of the reference.
Accuracy:
Linearity
Temperature Coefficient
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±.02% of full scale over entire negative to positive range.
±5 PPM per °C typical
±15 PPM per °C maximum, voltage
±30 PPM per °C maximum, current
Input Impedance:
Voltage Inputs:
Greater than 10 megohms at DC
AC impedance, 20K ohms in series with .47 mfd capacitor.
Current Inputs:
250 ohm, 0.1% precision shunt
Common Mode Rejection:
Voltage Range - Peak signal input must be between +13 and –13 volts with
respect to the ANLGCOM terminal.
Sensitivity:
Response to common mode signals within the above limits is typically 70 dB
CMRR, corresponding to a .02% full scale reading for a 0V input at 10 volts
common mode.
NOTE: Continuous input signals beyond the common mode range can result in
abnormal conversions without causing alarms.
Crosstalk:
High-speed inputs on the Base Converter module may show some interaction
between adjacent channels. This is typically .04% of the difference between the
affected input and the adjacent channel input levels. The effect can be
minimized by arranging inputs with similar levels on adjacent channels. There
is no measurable interaction between Expander input channels.
Conversion Rate:
Base Converter inputs updated sequentially about every 2.4 ms to 2.8 ms (maximum) for all 8 channels.
One Expander input updated during each scan of the Base Converter inputs.
Time between Expander updates = 44.8 x N ms (N = number of Expander
modulespresent).
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Table 5. Analog Input Specifications (continued) [
Response Time:
Each input has a low pass filter with a 100 radian/second (0.01 second) cutoff.
A digital filter on the Base Converter input channels adds a second pole at 450
radians/second. A sample and hold maintains full resolution.
Settling times, to the specified accuracies, for a zero to full scale step input are as
follows:
5.0% 30 milliseconds
1.0% 42 milliseconds
0.5% 51 milliseconds
0.1% 67 milliseconds
Input Protection:
Inputs isolated from VME backplane - but not between input channels. They
are, however, protected from overvoltage to the levels listed below.
Impulse:
Electrostatic Discharge:
ContinuousOvervoltage:
Power Requirements:
RackBackplane
Field Side
[
Inputs normally not affected by common mode damped ringwave of up to
1000 volts peak. Common or transverse mode peaks up to 2500 volts cause no
damage, but may cause occasional bad data if they occur coincidentally with
conversion of the affected channel.
Inputs survive up to 15KV ESD.
Inputs survive common mode or normal mode 120 VAC or 125 VDC fault for at
least 1 minute. Longer times may damage input current limiting resistor.
Damage limited to only the affected input.
+5 volts at 0.8A (4 watts) maximum for Base Converter
+5 volts at 0.4A (2 watts) for each Expander module
No power required for the module; however, current for 4 to 20 mA inputs
must be user supplied.
Refer to GFK-0867B, or later for product standards and general specifications. For installations requiring compliance
to more stringent requirements (for example, FCC or European Union Directives), refer to Installation Requirements for
Conformance to Standards.
Table 8. Ordering Information
Description
Analog Input Base Converter Module
Catalog Number
IC697ALG230
Analog Input Expander Modules
Current, 4 to 20 mA
IC697ALG440
Voltage, –10 to +10 Volts
IC697ALG441
Note: For Conformal Coat option, or Low Temperature Testing option please consult the
factory for price and availability.
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