BU4.2:CL6921
May 1996
PROVOXr Process Management Systems
Type CL6921 External Interface Card
The Type CL6921 External Interface Card is a
microprocessor based interface that provides
communication between various non-PROVOX
devices and a SR90 or SRx controller. The card
communicates with the controller via a serial I/O bus
and provides two 25-pin RS-232C (or two current loop)
connectors for communication with field devices. The
external interface card can be configured (via the
installed firmware) to support either of the following:
Weigh Scale Interface
Allen-Bradley PLC Interface
While the current loop serial connector is used
exclusively with the weigh scale interface devices, the
RS-232C is used with the Allen-Bradley Highway
Interface Module.
Interfaces to other types of field devices are available
on customer request.
The external interface card can be installed in any of
14 slots in the Type CL6701 Control I/O Cardfile.
The coaxial cable connecting the controller to the
control I/O cardfile can be up to 5000 feet (1524 m),
allowing the customer to position the cardfile and
external interface card outside the control room and
closer to field devices.
Functional Description of Weigh
Scale Interface
The external interface card when configured as a
weigh scale interface (WSI), provides two RS-232C
connectors to support Toledo, Masstron and BLH
weigh scale devices. Communication between the
weigh scale and the external interface card is via a
current loop serial port and user-supplied twisted pair
cable not to exceed 1000 feet (305 m). Each weigh
scale port is configured for channels 1 to 8 which
emulates an eight-channel analog input card. The
weigh scale input data (ASCII encoding) is converted
to the PROVOX data highway percent format for use
by other PROVOX system devices. Figure 1 illustrates
the external interface card configured as a weigh
scale.
Refer to the user manual supplied with the particular
weigh scale for additional information.
Primary Data Highway
SR90 or SRx
Controller
Type CL6921 External
Interface Card
Port A
D001389X042
Port B
Secondary Data
Highway
I/O Card File
Weigh Scale
I/O Bus
Figure 1. Type CL6921 External Interface Card Weigh Scale Configuration
Weigh Scale
X00750–A8
BU4.2:CL6921
May 1996
Page 2
Allen-Bradley PLC Interface
Features
The following features are implemented in the
Allen-Bradley PLC Interface:
Simulation Mode
Configurable PLC Address
Configurable Baud Rate (four options)
Configurable PLC Address Table (two options)
Functional Description of the
Allen-Bradley PLC Interface
function of the external interface card. Communication
between the Allen-Bradley Highway Interface and
Port A of the external interface card, illustrated in
Figure 2, is via a user-supplied RS-232C cable not to
exceed 50 feet (15.25 m). When used as the
Allen-Bradley (A-B) interface, the external interface
card is capable of emulating up to 56 discrete and
analog I/O cards (896 channels).
I/O port A can also be used for RS-232 serial
communications with a computer for process
simulation data for a SR90 or SRx controller.
Each emulated card can be addressed as any valid I/O
card address.
Support for an Allen-Bradley Programmable Logic
Controller (A-B PLC), is provided by the I/O coupler
Primary Data Highway
Type CL6921 External
Interface Card
SR90 or SRx
Controller
Port A
Secondary
Data Highway
I/O Card File
Allen–Bradley\
Hwy Interface
I/O Bus
Allen–Bradley Data Highway
or Data Highway Plus
Figure 2. Type CL6921 External Interface Card Allen-Bradley PLC Configuration
Allen–Bradley
PLC
X00750–A9
When the external interface card is used as an A-B
PLC interface, it emulates the functionality of a weigh
scale input, analog and discrete cards including, pulse
count input and time proportional output. The A-B
interface reports changes is card status, channel
status and channel data to the controller.
converted from PROVOX highway percentage values
to A-B analog/digital (A/D) counts.
When the external interface card is configured to
emulate a discrete I/O card, channels configured as
discrete momentary outputs should be grouped
together. Momentary or latching outputs must be
configured consecutively as either channels 1 through
8 or channels 9 through 16, and cannot be mixed
within the same channel group. Channels can also be
configured as discrete inputs.
The A-B interface can emulate the time proportional
output (TPO) functionality of a discrete I/O card. It
accepts TPO output change requests and pulses the
output channel to the PLC. The PLC has on its input
channel, a one state followed by a zero state. The
input remains at the zero state until the next TPO
output change request.
The emulated analog output card provides analog
output data to the A-B PLC. The output values are
The emulated analog input card can handle up to 16
channels per card. The analog input values are
converted from the A-B A/D counts to PROVOX
highway percentage.
The A-B interface can emulate the pulse count input
(PCI) functionality of a discrete I/O card. The emulated
PCI functionality requires that all eight channels be
BU4.2:CL6921
May 1996
Page 3
configured as PCI type channels. PCI channels are
configured in channels 1 through 8. The A-B PLC
provides the pulse rate and accumulation values for
the PCI channel.
rate depends on the configuration, the RS-232C
communications rate, and the response time of the
A-B PLC.
When the A-B interface is configured to emulate the
WSI card, ports A and B must be configured for valid
WSI types (Toledo, Masstron or BLH). The WSI
channels are configured in channels 1 through 8. The
A-B PLC provides the weigh scale input value as an
A/D count. The A/D count is converted to PROVOX
highway percent in the same manner as emulated
analog input channels. To the A-B PLC, the emulated
WSI card appears to be an channel analog input card.
Status Indicators
All input channels are updated at the same rate. This
A light emitting diode (LED) on the front bezel of the
external interface card will blink when the card is first
powered up, indicating that the self-test is being
performed and the card is waiting for it’s configuration
data. Under normal operation the LED is ON. A
blinking LED indicates that no configuration data is
present or that the external RS-232C interface cables
have not been connected. A failure of the external
interface card turns the LED OFF.
Specifications
Power Requirements:
Inputs
24 Vdc at 250 mA
Ports A and B accept ASCII data via a
serial 20 mA link from two separate
weigh scales
Comm Format
Toledo
Mastron
Model 8132, 8140, 8142 scales, at
4800 baudrate (11 bit ASCII, 7 data
bits, 1 start bit, 2 stop bits, even parity)
Model M5000 scales, at 4800
baudrate (10 bit ASCII, 8 data bits, 1
start bit,1 stop bit, no parity)
BLH
Model 4310A or 4315A scales, at
9600 baudrate (11 ASCII, 7 data bits,
1 start bit, 2 stop bits, even parity)
Resolution
Equal to 0.004 percent of the
configured scale range of the interface
unit
Accuracy
Equal to 0.004 percent of the
configured scale range of the interface
unit, or to the capability of the scale, if
the scale is less accurate
Range
Out-of-Range
Reporting
Each input has 14 configurable ranges
for gross weight in pounds or
kilograms, as defined during scale
setup
Accurately reports gross weights as
much as 14 percent below or above
the specified range.
Response Time
Typical time for the controller output to
respond to weight placed on scale is 0.5
sec. Worst-case time is 0.7 to 1.0 sec,
depending on the weigh scale used and
the controller loading.
Allen-Bradley
PLC
I/O Capacity
56 I/O cards (896 channels)
Number of
Devices
1
Comms
Link Supported: RS-232C
Speed: 19,200 baud
Format: 8 data bits, 1 stop bit, even
parity
Electrical
Classification
Refer to Non-Hazardous Area
Classification Bulletin, PS4.7:001 (A1)
Size and Weight
8.66 inches by 9.18 inches (220 mm by
233 mm).
Approximately 1 pound (0.454 kg)
Indicators
Green LED ON indicates normal
operation
ElectroMagnetic
Compatibility
Complies with European Standards
EN50081-2:1993 and
EN50082-2:1995
BU4.2:CL6921
May 1996
Page 4
Specifications (continued)
The standard Allen-Bradley Interface consists of an
External Interface Card with Allen-Bradley applications
firmware. The EIC can be used to interface a PROVOX
SR90 or SRx controller to one of the following
Allen-Bradley Programmable Logic Controllers.:
Mini PLC-2, 2/02. 2/05, 2/15, 2/16, 2/17
PL2/20 and 2/30
PLC-3 and 3/10
PLC-4
PLC-5/12, 5/15, 5/25, 5/30. 5/40. 5/60.
The EIC may also be compatible with other
Allen-Bradley or Allen-Bradley compatible devices,
however, the standard EIC is not compatible with the
Allen-Bradley SLC series controllers.
For further details on the specific Allen-Bradley
commands used by the EIC, consult the Installation and
Maintenance of Type CL6921 External Interface Card
(PN2.1:CL6921).
The EIC can also be used to interface with a VMS or
Windows NT computer running SIMVOX Simulation
Software for operator training, process simulation, and
configuration checkout.
Ordering Information
Operating Conditions
Operative
Limits (1)
Transport &
Storage
Limits (1)
41 & 131oF 32 &131oF
73 & 81oF
(23 & 27oC) (5 & 55oC) (0 & 55oC)
–40 & 149oF
(–40 & 65oC)
3.5oF/h
(2oC/h)
36oF/hr
(20oC/hr)
9oF/min
(5oC/min)
18oF/min
(10oC/min)
35 to 45%
10 & 90%
5 & 95%
5 & 95%
Reference
Conditions Limits (1)
Ambient
Temperature (2)
Maximum
Temperature
Variation
Ambient
Relative
Humidity
(without
condensation)
Electromagnetic
Field (3)
Normal
Limits (1)
100 milli10 volts per 30 volts per
volts per
meter, 20 to meter, 20 to
meter, 20 to 1000 MHz 1000 MHz
1000 MHz
N/A
1.
ISA Standard ISA-SS71.4–1985.
2.
SAMA Standard PMC33.1-1978 explains these
conditions,,which apply only when the unit is installed in a
console bay or cabinet and all doors are closed.
Application Firmware
Weigh Scale Interface
When ordering, specify:
Type CL6921 External Interface Card
Allen-Bradley PLC Interface
Per request
Cable (customer supplied)
External interface card with application firmware
The contents of this publication are presented for informational purposes only, and
while every effort has been made to ensure their accuracy, they are not to be construed
as warranties or guarantees, express or implied, regarding the products or services
described herein or their use or applicability. We reserve the right to modify or improve
the designs or specifications of such products at any time without notice.
PROVOX is a mark of one of the Fisher-Rosemount group of companies. All other
marks are the property of their respective owners.
 Fisher-Rosemount Systems, Inc. 1996. All rights reserved. Printed in USA.