Siemens CPU 948 User Manual

1.8 Converting User Programs of the CPU 928B for the CPU 948
The following section informs you about the points you should
remember when you convert user programs written for the CPU 928B
for use on the CPU 948.
Operations In the following operations, note the differences in the execution and
handling (among other things the different memory utilization).
Operations CPU 928B CPU 948
IA/RA (disable/enable
interrupts)
All process interrupts are disabled or
enabled
Only the process interrupts via input
byte IB 0 are disabled or enabled.
Instead of these operations, use the
special function OBs OB 122 or
OB 142.
LIR/TIR 16 bit long addresses are used. 20 bit long addresses are used.
Adaptation is necessary.
Block transfer opera-
tion TNB
16 bit long addresses are used. The operation does not exist.
Use TNW for block transfer from the
8-bit to the 8-bit area.
Block transfer opera-
tion TNW
- 16 bit long addresses are used.
- Block transfers from the 8-bit to the
8-bit area and vice versa are
possible.
- 20 bit long addresses are used.
Adaptation is necessary.
- only block transfers from the
8-bit to the 8-bit area and from the
16-bit to the 16-bit areas possible
with TNW.
- for the block transfer from
the 8-bit to the 16-bit area use
the operation TXB,
- for the block transfer from
the 16-bit to the 8-bit area use
the operation TXW.
(TXB and TXW do not exist on
a CPU 928B)
All operations with the
BR register
The BR register is 20 bits wide. The BR register is 32 bits wide.
Adaptation is necessary.
Converting User Programs of the CPU 928B for the CPU 948
CPU 948 Programming Guide
C79000-G8576-C848-04
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Siemens CPU 948 Specifications

General

Brand	Siemens
Model	CPU 948
Category	Controller
Language	English