I believe your vehicle is a Hispano Suiza T-69 from 1936.
I do not know much about this one but I do know that during the Spanish Civil War hundreds of improvised armoured cars were built on many different truck chassis on both sides of the conflict.
Most that I have seen were built on Chevrolet, Ford and Dodge chassis and some were built in small series. Many were built in railroad shops from what I have read.
The modern day equivalent may be the "Technicals" that one sees used in Africa and the Middle East based on Toyota, Nissan and other Japanese pickup chassis.
Edit: I forgot to post the photo that I had of the vehicle, this one showing the car with armament.