3 Basics
3.2 Communication
HCS4x00Library
Entry ID: 109478117, V2.2.1, 09/2018
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When using a “PM4000 U/I”, data record 202 enables the reading of measured
values.
When using the POM 4220 Highend, you can change its configuration data (for
detecting a partial load interruption in case of heating elements connected in
parallel) for each channel during operation via data record 2.
Additionally, you can read out the measured values (current and power) of the
POM4220 Highend for each channel via data record 203.
Note
Further information on the data records is available in the operating instructions
on the SIPLUS HCS4200 (
) heating control systems.
Validity bit "valid"
In the library, each data record on the writing side (DB "LHcs4x00_Put") and on the
reading side ("LHcs4x00_Get") has a validity bit "valid". It serves to check whether
acyclic data have been transferred successfully and whether these data are up to
date (for read and write access).
Thus, each data record that has been transferred successfully to the SIPLUS HCS
resets not only the write validity bit in DB "LHcs4x00_Put" ("valid" = true), but also
the read validity bit in DB "LHcs4x00_Get" ("valid" = false).
Only after successfully reading the data record again, "valid" is set in DB
"LHcs4x00_Get". Thus, a matching of the written and read data record is signaled
if both validity bits are set ("valid" = true). When resetting the HCS via data record
190 or communication failure between CPU and HCS, all validity bits are set to
"false".
Figure 3-3
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