Faq And Troubleshooting; Known Issues; Bl2500 With Rabbit 3000 Microprocessor Revision 0 (Il1T); Bl2500 With Large Sector Flash - OEM BL2500 User Manual

PLC BL2500 User's Manual
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7.1 KNOWN ISSUES

7.1.1 BL2500 with Rabbit 3000 Microprocessor Revision 0 (IL1T)

The Rabbit microprocessor R3000 Revision 0 (IL1T or IZ1T) has a bug on the parallel port F (see Z-
World's TN228 http://www.zworld.com/documentation/docs/refs/TN228/TN228.pdf). The analog inputs
and analog outputs use the PWM which uses parallel port F. Thus any operation on analog I/O affects the
normal operation of outputs, serial RS485 transmitter enable signal, SPI enable signal and LEDs DS3
and DS4.
If you have an SBC BL2500 with the Rabbit 3000 microprocessor revision 0 (IL1T or IZ1T) and want to
use the analog features bear in mind that outputs 0 to 3, RS485 and RabbitNet can not be used.
For more information about the Rabbit 3000 microprocessor revisions see Appendix B of [3].

7.1.2 BL2500 with Large Sector Flash

The PLC kernel writes the ISaGRAF application on flash to preserve the application on power
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cycles. This operation is done only with BL2500 with small sector flash.
ISaGRAF application on Battery-Backed RAM if the BL2500 has large sector flash.

7.1.3 ISaGRAF Floating Point Arithmetic

The floating point arithmetic implemented by Dynamic C for the Rabbit 3000 microprocessor is not 100%
compliant with the IEEE Standard. When doing arithmetic operations with numbers close to the upper
limit (3.4E38) instead of causing an overflow the result goes beyond the limits set by the standard.
External applications, such as ISaGRAF Debugger, monitoring those values will fail because those values
are invalid floating point (NaN).
When this condition happens, the ISaGRAF Debugger stops but leaves some processes running. If you
experience this problem, close all ISaGRAF applications (including the Project Management). Re open
the Project Management to resume ISaGRAF development.

7.1.4 Reading/writing 32-bit integer/real analog variables via Modbus

PLC supports reading and/or writing 32-bit integer/real analog variable through Modbus.
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Requests are handled by using two consecutive words (multiple registers) in little endian format, i.e. the
less significant word goes first. The constraint is the Modbus address for analog variables must be odd
number.
OEM Technology Solutions

7. FAQ AND TROUBLESHOOTING

FAQ and Troubleshooting
PLC kernel saves the
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