How do I turn on and turn off a relay?

[mkaivs]

I want to use a PCIe-IDIO-24 Isolated Digital I/O Card to turn on / turn off switches. How do I turn on/off a single relay or multiple relays at once using a bit mask? Something like:

// single write: void write(int fd, uint8_t relay_index, uint8_t value);
write(fd, 0, 0); // turn of relay at index 0
write(fd, 0, 1); // turn on relay at index 0

// batched write: void write(int fd, uint32_t value);
write(fd, xFFFFFF); // turn on all 24 relays
write(fd, 0); // turn off all 24 relays
write(fd, xF00007); // turn on relays at index 0-2 & 20-23, turn off relays at index 3-19

// single read: void read(int fd, uint8_t relay_index, uint8_t* value);
uint8_t* value;
read(fd, 0, &value); // value is set to 1 if relay is on, 0 if relay is off

// batched read: void read(int fd, uint32_t* value);
uint32_t* value;
read(fd, &value); // value is set to 0xF if relays at index 0-3 is on 

[JHentges]

Hello, John Hentges here from Software at ACCES.

The device does not support single write, but your batched write is pretty close.

apci_write32(fd,         0, //ignored         2, // BAR#; virtually all cards use BAR2 exclusively         0, // register offset see page 11 of hardware manual         0x40AAAAAA, // data: turn on all odd FET bits, and (if configured as outputs) turn off TTL bits 0-5 and bit 7 but turn on TTL bit 6. (writes to inputs are ignored) );

apci_read32(fd, 0, 2, 4, &data); // read 32 bits of data from +4->+7.  MSB is TTL input/readback

Let me know if you'd like any additional details.  I am here to help!

John Hentges | Director of Software Engineering and Digital Design | ACCES I/O Products, Inc. http://accesio.com/contact-us @. @.> | (858) 467-5582  | JohnHentges-ACCESIO#7568 on Discord

On 1/6/2023 1:33 PM, mkaivs wrote:

I want to use a PCIe-IDIO-24 Isolated Digital I/O Card https://accesio.com/product/pcie-idio-24/ to turn on / turn off switches. How do I turn on/off a single relay or multiple relays at once using a bit mask? Something like:

|// single write: void write(int fd, uint8_t relay_index, uint8_t value); write(fd, 0, 0); // turn of relay at index 0 write(fd, 0, 1); // turn on relay at index 0 // batched write: void write(int fd, uint32_t value); write(fd, xFFFFFF); // turn on all 24 relays write(fd, 0); // turn off all 24 relays write(fd, xF00007); // turn on relays at index 0-2 & 20-23, turn off relays at index 3-19 // single read: void read(int fd, uint8_t relay_index, uint8_t value); uint8_t value; read(fd, 0, &value); // value is set to 1 if relay is on, 0 if relay is off // batched read: void read(int fd, uint32_t value); uint32_t value; read(fd, &value); // value is set to 0xF if relays at index 0-3 is on |

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[mkaivs]

@JHentges

Thank you so much for the explanation, I've got a much better idea of how to use the provided apcilib library now.