In order for each primary block in the database to receive data, you
must connect to your I/O using an I/O driver. The driver you select depends
on your process hardware. GE sells drivers for many types of hardware.
Contact your GE Sales Representative, or refer to our web site at at https://digitalsupport.ge.com
for a list of available drivers.
After you purchase a driver and install it, you can start specifying
I/O points you want the current block to use. If the I/O point does not
exist, Database Manager starts your I/O driver configuration program so
you can add it. Refer to your I/O driver documentation to learn how to
add an I/O point to your driver configuration.
iFIX supplies an OPC Client I/O driver, as well as two simulation drivers.
OPC Client Driver
The OPC Client driver provides the interface and communications protocol
between OLE for Process Control servers and iFIX.
The OPC Client driver supports the following features:
- Analog register and
digital register database blocks
- Special addressing
for analog output and digital output blocks
- Text blocks
- Item property I/O
addresses for text blocks
- Block writes
- Data arrays
- Exception-based processing
- Latched data
Simulation Drivers
You can use the SIM and SM2 to test your chains before you connect to
real I/O. The simulation drivers are matrixes of addresses. Database blocks
read values from and write values to these addresses. If one block writes
to a specific address, other blocks can read the same value from the same
address. You can save these values when you save the process database;
however, iFIX removes them from memory when SAC starts or you reload the
database.
Both drivers have the following in common:
- Provide a matrix
of addresses that database blocks can read from and write to.
- Support analog and
digital database blocks.
- Support text blocks.
The drivers differ in the following ways:
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The SM2 driver...
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The SIM driver...
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Provides three independent sets of registers. Analog
blocks automatically access the analog registers, digital blocks automatically
use the digital registers, and Text blocks automatically access the text
registers.
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Provides one set of registers shared by both analog,
digital, and text blocks.
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Changing a register in one set does not change the
same register in the other set. For example, if you change the value of
the analog register 1000, the value of the digital register 1000 is unchanged.
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Changing an analog register in the SIM driver modifies
the register for analog, digital, and text reads. For example, if you
change the value of the analog register 1000, you also modify the value
of the same digital register.
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Provides 20,000 analog, 20,000 16-bit digital registers,
and 20,000 text registers.
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Provides 2000 analog and digital registers, a total
of 32,000 bits.
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Stores analog values in 4-byte (32-bit) floating point
registers, numbered 0 to 19999. Incoming values are not scaled.
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Stores analog values in 16-bit integer registers,
numbered 0 to 2000. Incoming 32-bit values are scaled to 16-bit values
(0 - 65535).
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Digital values are stored in 16-bit integer registers,
numbered 0 to 19999.
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Digital values are stored in 16-bit integer registers,
numbered 0 to 2000.
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Text values are stored in 8-bit registers numbered
0 to 19999. Each register holds one text character for a total of 20,000
bytes of text.
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Text values are stored in the same area as analog
and digital values, numbered 0 to 2000.
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Provides a register to simulate communication errors.
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Cannot simulate communication errors. However, the
SIM driver does provide registers RA through RK and RX through RZ to generate
random numbers. For more information, refer to the Using
Signal Generation Registers in the SIM Driver section.
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Supplies a C API that allows applications to access
SM2 analog, digital, and text values.
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Does not support a C API for accessing SIM values.
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Supports exception-based processing.
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Does not support exception-based processing.
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Supports latched data for Analog Input, Analog Alarm,
Digital Input, Digital Alarm and Text blocks when a simulated communication
error is enabled.
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Does not support latched data.
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Can read and write the individual alarm status of
each SM2 register.
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Cannot read and write the individual alarm status
of any SIM register.
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Does not provide alarm counters.
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Provides alarm counters that show the general alarm
state of a SCADA server. For more information, refer to the Using Alarm Counters chapter of the Implementing Alarms and Messages manual.
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See Also
