User Manual

Table Of Contents

9. External DATA Source Unit (EDSU) – 5

9.1 Overview

Cooke 5I lenses have additional capabilities and commands, not available to the

other lens types, which enable an external device, (called an External Data Source Unit

or EDSU,) connected to the external RS232 channel of the lens, to perform special

operations.

Under normal operation, a command is sent to a lens requesting information, the

lens generates a data string and sends this information to the camera interface, the

external interface or both. This data can then be stored by the camera or external

device for post processing. 5I lenses have the additional facility to collect a data

stream from an External Data Source Unit (EDSU) and then append this data to the lens’

normally generated data string.

During the “append” operation, the EDSU generated data stream is stored within the lens

and then appended to every data block that is sent to the Camera. The EDSU can turn the

append operation “ON” and “OFF”. The lens has space to store a single EDSU STRING, and

this same string is used for every data block until it is updated by the EDSU or the append

function terminated. The data rate from the EDSU does not need to match the data rate

between camera and lens. If data strings from the EDSU (which are to be appended) arrive

slower than the rate of data strings being generated by the lens for the camera, then multiple

strings to the camera will have the same EDSU append string added.

At the same time that the EDSU is sending data to the lens, it can also request that

the lens send the normal data stream back to it.

9.2 Principals of Operation

1. EDSU issues OS command to determine settings for current channel.

2. EDSU issues OT command to determine settings for opposite channel.

3. EDSU establishes format of data and data rate to send to lens.

4. EDSU issues OC command and verifies response from lens. (An internal EDSU buffer

for the EDSU data in the lens will be cleared.)

5. Data sent to the opposite (camera) interface will now append the contents of EDSU

buffer to the normal data stream. (If buffer remains empty, no data will be

appended.)