ADLINK PCI-7260 - Manual (Page 39)

Operation Theorem 29
4 Operation Theorem
4.1 Non-Latching Relay Output
One of the innovative features on PCI-7260 is the 8-channel non-
latching relay output. The PCI-7260 contains only one type of non-
latching relay : 1 coil 1 Form A 1 Form B. Figure 4.1 shows the
latching relay contact arrangement under RESET condition.
Figure 4-1: 1 Coil Non-Latching Relay (RESET Condition)
Each non-latching relay on PCI-7260 has one coil which controls
each non-latching relay, we need only one control bit. What we
have to do is to energize and deenergize the coil when switching
RESET condition to SET condition. After the contact switches to
the opposite position at a steady state, we still cann’t cut out the
current on the coil and the contact will not change. Under the
scheme of controlling latching relay, we define the SET condition
control bit as “0” and the RESET condition control bit as “1”. For
more details about the non-latching relay control register, refer to
section 3.3.
PCI-7260 also provides a software function for user to control the
non-latching relays. Using this function, relay control is as simple
as the general relay. Instead of writing 32-bit data to the relay out-
put register, user only needs to prepare 8-bit data and each bit
represents a relay’s status. Value ‘0’ represents SET condition
and value ‘1’ represents RESET condition. For more details about
the relay output function library, refer to section 5.3.
The relay output contacts are rated for a maximum of 5A at
250VAC (resistive), or 5A 30VDC. You should reduce these rat-
ings for inductive loads. For more detailed information of relay
contact, please refer to Appendix A.