Saia-Burgess Controls AG
Manual I/O-modules for PCD1 │ PCD2 series │ Document 27-600 – Release ENG09 │ 2019-05-01
5-100
I/O modules PCD1|PCD2
PCD2.W525 Combined analogue input/output module with galvanic isolation
5
Function
Power Supply
PCD2.W525 has to be supplied externally! This power supply is galvanically iso-
lated to both, the Saia PCD
®
and the I/Os of W525. Furthermore, the design allows
using the same power supply for the Saia PCD
®
and for W525 without loosing the
galvanic isolation. These schematics show the different zones of isolation:
Timing
●
Inputs
○
Internally, W525 finishes acquiring every 2 ms a new value for every
input channel
○
This value is always ready to be read by the Saia PCD
®
.
○
Dependent on the Saia PCD
®
speed, the transmission time of a single
16-Bit scaled value (of a single input channel) takes typically 100 μs (on
a PCD2.M480) or 600μs (on a PCD2.M170)
●
Outputs
○
Internally, W525 outputs the last received output value from Saia PCD
®
with a maximum delay of 2 ms.
○
Dependent on the Saia PCD
®
speed, the transmission time of a single
16-Bit scaled output value takes typically 100 μs (on a PCD2.M480) or
600 μs (on a PCD2.M170).
Filter
●
Inputs
There are two factors, which have filtering effects to the acquired values:
○
The base hardware filter with a time constant of 2 ms. This filter attenu-
ates the input signal by 6 dB/decade at a cut-off frequency of 80 Hz.
○
The second influence is caused by software and results in a delay of
the acquired value for 2 ms with a notch filter characteristics at 500 Hz if
no software based 50 Hz / 60 Hz filter is selected.