Hardware Manual PCD 1 / PCD 2 Series│Document 26 / 737│Edition EN 15│2008-07-22

Saia-Burgess Controls AG

Backup of the user program

CPUs and expansion housings

3

Storing a   text/DB on  the flash   card,   SYSWR   K   9000

Instruction: SYSWR K 90001)^

K number ; address of the texts/DBs as

; K constant or in a

; register, existing text/DB addresses in

; the range >= 4000 may be used

1) Alternatively, the value 9000 can be passed in a register. On the PCD3, the instruction

SYSWR K 3000 is used for the same function. For reasons of compatibility, SYSWR

K 3000 can also be used on the PCD1/2, but this alternative was only integrated into the

firmware in the 2nd half of 2004

Accu status after execution:

low: the text/DB has been saved, and the flash card is ready

for new SYSWR instructions

high: the last instruction was not processed to completion;

before further SYSWR K 900x instructions, a SYSRD

K 9000 must be executed to check the readiness of the

flash card

When using the instruction SYSWR K 9000, note the following:

 The flash card can be written to a maximum of 100'000 times, so it is not permis-

sible to invoke the instruction in a cyclical manner or at short intervals

 A SYSRD K 9000 must be executed before this instruction, to test whether the

flash card is available and ready

 the processing time for the instruction may be up to 100 ms. At that point, there is

no guarantee that all of the text/DB has been written (the process will continue in

background). For this reason, the instruction must not be invoked in XOB 0 (XOB

for a power outage) or during time-critical processes

 if errors occur during processing, e.g. because no flash card is plugged in, XOB 13

will be invoked (where present), or the Error LED will be set

i

       when starting the PCD after a loss of RAM memory, the state of the texts/DBs

after the last download is restored, even where the SYSWR K 9000 instruction has

been used to store newer versions.

 Within the maximum number of write cycles, a text/DB can be stored any number

of times, without the flash card becoming over-full.