ADLINK Technology PCI-7251 - Using Isolated Input

Operation Theorem •• 19
NO
COM
Control Bit = High (1)
NO
COM
Control Bit = Low (0)
Form A relay only has two contacts : NC (Normal Close) and COM
(Common). The COM post can make contact either NO post or not
contact NO post. When the control bit is high (1), the COM post and
NO post are contacted. If the control bit is low (0), the COM post and
NO post does not make contact.
In normal power-up and reset, the relay is in low status.
The relay output contacts are rated for a maximum of 0.5A at 120VAC
(resistive), 1A 24VDC, or 0.3A 60VDC. You should reduce these
ratings for inductive loads. For more detailed information of relay
contact, please refer Appendix B.
4.2 Using Isolated Input
The PCI-7250 (or PCI-7251) contains 8 identical opto-isolated control
input channels. The circuit diagram of the isolated input channel is
shown.
V
IN
1.2k
Ω
Ri
PC-814
(opto-isolator)
I
F
DInH
IGND
The digital input is first routed through a photo-coupler (PC-814), so
that the connection are not polarity sensitive whether used on AC or