To get more information about the Hardware Abstraction Layer and how it works, please have a look into the HAL described on the eeros wiki.
EEROS for the Beagle Bone Blue is using the robotis_cape_library. You'll find the wrapper and its functions in the bbblue-eeros folder.

If you want to run a motor with EEROS you need to define a Peripheral Output with the respective “signalId” used in the HAL-Configuration file. As you can see in the HAL-Configuration file for the Delta roboter in “subdevice2” the type for the motors is set to “AnalogOut”. In this subdevice section the 4 motors are configured to match the functions of the robotics_cape_library. In the EEROS application for the Delta roboter you can set a motor voltage of -8.0V to 8.0V. The HAL gets this values and wraps it to match the values of the robotics_cape_library which then runs the motors with the desired voltage.

The Delta roboter has two different encoders. The ieh2-4096 and the hem3-256.

{
	"device0": {
		"library": "libbbblueeeros.so",
		"devHandle": "dummy",
		"subdevice0": {
			"type": "DigOut",
			"channel0": {
			        "signalId": "onBoardGreen"
			},
			"channel1": {
				"signalId": "ledBlue"
			},
			"channel49": {
				"signalId": "ledRed"
			},
			"channel116": {
				"signalId": "onBoardRed"
			},
			"channel98": {
				"signalId": "emag"
			}
		},
		"subdevice1": {
			"type": "DigIn",
			"channel0": {
				"signalId": "buttonMode"
			},
			"channel1": {
			        "signalId": "buttonPause"
			},
			"channel97": {
				"signalId": "buttonBlue"
			},
			"channel57": {
				"signalId": "buttonRed"
			},
			"channel113": {
				"signalId": "buttonGreen"
			}
		},
		"subdevice2": {
			"type": "AnalogOut",
			"channel1": {
				"signalId": "motor1",
				"scale": [ { "id" : "dac",
							"minIn": 	-1.0, 	"maxIn": 	1.0,
							"minOut": 	-8.0, 	"maxOut": 	8.0 }
 
					 ],
				"range": [ { "id" : "dac",
						      "minIn": 		-0.75,	"maxIn": 	0.75,
							"minOut": 	-6.0, 	"maxOut": 	6.0 }
					 ],
				"unit": "V"
			},
			"channel2": {
				"signalId": "motor2",
				"scale": [ { "id" : "dac",
							"minIn": 	-1.0, 	"maxIn": 	1.0,
							"minOut": 	-8.0, 	"maxOut": 	8.0 }
					 ],
				"range": [ { "id" : "dac",
						      "minIn": 		-0.75,	"maxIn": 	0.75,
							"minOut": 	-6.0, 	"maxOut": 	6.0 }
					 ],
				"unit": "V"
			},
			"channel3": {
				"signalId": "motor3",
				"scale": [ { "id" : "dac",
							"minIn": 	-1.0, 	"maxIn": 	1.0,
							"minOut": 	-8.0, 	"maxOut": 	8.0 }
					 ],
				"range": [ { "id" : "dac",
						      "minIn": 		-0.75,	"maxIn": 	0.75,
							"minOut": 	-6.0, 	"maxOut": 	6.0 }
					 ],
				"unit": "V"
			},
			"channel4": {
				"signalId": "motor4",
				"scale": [ { "id" : "dac",
							"minIn": 	-1.0, 	"maxIn": 	1.0,
							"minOut": 	-6.0, 	"maxOut": 	6.0 }
 
					 ],
				"range": [ { "id" : "dac",
						      "minIn": 		-1,	"maxIn": 	1,
							"minOut": 	-6.0, 	"maxOut": 	6.0 }
					 ],
				"unit": "V"
			}
		},
		"subdevice3": {
			"type": "Fqd",
			"channel1": {
				"signalId": "enc1",
				"scale": [ { "id" : "gear",
							"minIn": 	0, "maxIn": 6.283185307,
							"minOut":	0, "maxOut": 477.522083346 },
					   { "id" : "enc",
							"minIn": 	0, "maxIn": 477.522083346,
							"minOut":	0, "maxOut": 311296},
					   { "id" : "fqd",
							"minIn":	0, "maxIn": 311296,
							"minOut":	0, "maxOut": 1245184}
					 ],
				"range": [ { "id" : "gear",
							"minIn": 	0, "maxIn": 6.283185307,
							"minOut":	0, "maxOut": 477.522083346 },
					   { "id" : "enc",
							"minIn": 	0, "maxIn": 477.522083346,
							"minOut":	0, "maxOut": 311296},
					   { "id" : "fqd",
							"minIn":	0, "maxIn": 311296,
							"minOut":	0, "maxOut": 1245184}
					 ],
				"unit": "rad"
			},
			"channel2": {
				"signalId": "enc2",
				"scale": [ { "id" : "gear",
							"minIn": 	0, "maxIn": 6.283185307,
							"minOut":	0, "maxOut": 477.522083346 },
					   { "id" : "enc",
							"minIn": 	0, "maxIn": 477.522083346,
							"minOut":	0, "maxOut": 311296},
					   { "id" : "fqd",
							"minIn":	0, "maxIn": 311296,
							"minOut":	0, "maxOut": 1245184}
					 ],
				"range": [ { "id" : "gear",
							"minIn": 	0, "maxIn": 6.283185307,
							"minOut":	0, "maxOut": 477.522083346 },
					   { "id" : "enc",
							"minIn": 	0, "maxIn": 477.522083346,
							"minOut":	0, "maxOut": 311296},
					   { "id" : "fqd",
							"minIn":	0, "maxIn": 311296,
							"minOut":	0, "maxOut": 1245184}
					 ],
				"unit": "rad"
			},
			"channel3": {
				"signalId": "enc3",
				"scale": [ { "id" : "gear",
							"minIn": 	0, "maxIn": 6.283185307,
							"minOut":	0, "maxOut": 477.522083346 },
					   { "id" : "enc",
							"minIn": 	0, "maxIn": 477.522083346,
							"minOut":	0, "maxOut": 311296},
					   { "id" : "fqd",
							"minIn":	0, "maxIn": 311296,
							"minOut":	0, "maxOut": 1245184}
					 ],
				"range": [ { "id" : "gear",
							"minIn": 	0, "maxIn": 6.283185307,
							"minOut":	0, "maxOut": 477.522083346 },
					   { "id" : "enc",
							"minIn": 	0, "maxIn": 477.522083346,
							"minOut":	0, "maxOut": 311296},
					   { "id" : "fqd",
							"minIn":	0, "maxIn": 311296,
							"minOut":	0, "maxOut": 1245184}
					 ],
				"unit": "rad"
			},
			"channel4": {
				"signalId": "enc4",
				"scale": [ { "id" : "gear",
							"minIn": 	0, "maxIn": 5.8,
							"minOut":	0, "maxOut": 670.206432766 },
					   { "id" : "enc",
							"minIn": 	0, "maxIn": 753.982236862,
							"minOut":	0, "maxOut": 30720},
					   { "id" : "fqd",
							"minIn":	0, "maxIn": 30720,
							"minOut":	0, "maxOut": 122880}
					 ],
				"range":  [ { "id" : "gear",
							"minIn": 	0, "maxIn": 6.283185307,
							"minOut":	0, "maxOut": 753.982236862 },
					   { "id" : "enc",
							"minIn": 	0, "maxIn": 753.982236862,
							"minOut":	0, "maxOut": 30720},
					   { "id" : "fqd",
							"minIn":	0, "maxIn": 30720,
							"minOut":	0, "maxOut": 122880}
					 ],
				"unit": "rad"
			}
		}
	}
}