You can absolutely do this using [x, y] coordinates in your values array.
series: [
{
values: [
[1420070400000,35],
[1420156800000,42],
[1420243200000,67],
[1420329600000,89],
[1420416000000,25],
[1420502400000,50],
[1420588800000,75]
],
text:'Department 1'
},
]
Example: https://demos.zingchart.com/view/ON21QDRY