Hardware Manual

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

Saia-Burgess Controls AG

PCD2.W2x0

Input/output (I/O) modules

5

Temperature measurement with Pt 1000

In the temperature range – 50 °C to + 200 °C, the following formulae can be used for

working to an accuracy of ± 1 % (± 1.5 °C). Repeating accuracy is significantly higher.

T=temperature in ° C DV=digital value (0 ... 1023)

Example 1: digital value DV=562

temperature T in ° C?

DV=digital value (0 ... 1023) T=temperature in ° C

Example 2: preset temperature T = –10 °C

corresponding digital value DV?

Resistance measurement up to 2.5 kΩ

Special temperature sensors or any other resistances up to 2.5 k�� can be connected

to the PCD2.W220. The digital value can be calculated as follows:

where 0 ≤ DV ≤ 1023 and R=the resistance to be measured in ��.

DV=

4092 • R

(7500 + R)

T[° C]= - 261,8

DV

2.08 - (0.509 • 10-³ • DV)

T[° C]= - 261,8

562

2.08 - (0.509 • 10-³ • 562)

= 51.5 °C

DV=

2.08 • (261.8 + T)

1 + (0.509 • 10-³ • (261.8 + T))

DV=

2.08 • (261.8 - 10)

1 + (0.509 • 10-³ • (261.8 - 10))

= 464