The good news is that the Sony ER550 is listed as ONVIF Profile S compliant, so by definition of Profile S, it should support PTZ controls. I can't find a reference on the ONVIF page for the DLA1400. Knowing what version of ONVIF it supports is key.
What has Bosch technical support said? I'd want to, at least, verify that the DLA1400 supports Onvif Profile S / 2.x.
The DLA1400 is a storage device. You need a workstation running Bosch BVC software to control your PTZ.
You may also want to confirm the latest version of VRM 3.0 is installed on the Bosch recorder. This can be downloaded from the website. As Richard indicated above, Bosch Video Client is the appropriate client software provided for user functions.
Thanks guys, this is all helpfull. Unfortunately I'm slightly removed from the technical process being with another company. But can anybody confirm they have had this combination working through the BVC?
Undisclosed - if you are still in need of assistance here, feel free to contact me.
Thanks Mike. It looks like I'll have direct access to a machine soon so I'll keep you in mind.