C&H Technologies M222 - Manual (Page 17)

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4.0 OPERATION
The M222 is a register-based instrument that is controlled through a series of I/O registers
described in Section 3.2.1. The exact method of accessing and addressing the I/O registers is
dependent on the M-Module carrier used to interface the module to your data acquisition or test
system. Refer to the carrier’s documentation for information on the address mapping of an M-
Module’s I/O registers and to your system software documentation for details on data access.
Typically a high level driver is available to aid in control of the module. Refer to the software
driver documentation for instructions on using the driver.
4.1 RELAY OPEN/CLOSE
Each relay channel can be separately controlled with the Relay Register (Reg. 0x14). Writing a 1
to a bit will OPEN the relay (i.e., connect the common terminal to the normally closed terminal)
and writing a 0 to a bit will CLOSE the relay (i.e., connect the common terminal to the normally
open terminal) as shown in Figure 4.
Figure 4. Effects of Opening/Closing Relay
4.2 INTERRUPTS
The M222 can generate an interrupt request 16ms after a relay is opened or closed indicating that
the relay has settled. The interrupt must be enabled in the Control Register (Reg. 0x02).
M-module carriers and system controllers treat the interrupts differently. Refer to your carrier
and controller documentation to determine how to properly configure them to handle the M-
module interrupt request.
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