How do I read an I/O register using SNMP ?
I/O registers in the Barionet (1000 instances) either are tied to hardware or just hold values, as an interface to a BCL program in the Barionet. Registers can be polled and also controlled using standard SNMP get/set requests. For set operations, the community "private" needs to be used (default). These same registers can also be accessed using Modbus/TCP or ASCII control protocols (and even via cgi/web server).
You can easily control the relays, for example, by using SNMP set requests on registers 1 and 2.
The detailed register map is documented in the Barionet manual.
How do the registers map to Object ID's ?
This is defined in the Barionet MIB, which is included in the device (you can access it with the URL /barionet.mib on the device), and on the Barix website.
Here is, for example, the OID for register 201 (digital input 1): 22.214.171.124.4.1.174126.96.36.199.1.2.201
In some systems, you may be able to use a name like this:
SNMPv2-SMI::enterprises.174188.8.131.52.1.2.X - X being the register number, for example. 1..4 for the four relays on the Barionet 50
Specifically, for the relays and digital outputs, the following values can be used:
- 0 (reset the relay), 1 (set the relay),
- 2..998 .. pulse the relay for the value times 100ms (5 is 500ms, 50 would be 5 seconds)
- 999 to toggle the relay.
Example to activate relay 3 using snmpset on OSX:
snmpset -v 1 -c private 192.168.1.121 SNMPv2-SMI::enterprises.174184.108.40.206.1.2.3 u 1