General Concepts Of Using Geocom; General Concept Of Operation - Leica tps1100 Reference Manual

GeoCOM Reference Manual

General Concepts of Using GeoCOM

2 G C U G COM
ENERAL ONCEPTS OF SING EO
Here we will describe several aspects of using GeoCOM. One of them is how to
execute a function at a TPS1100 instrument.
The current implementation of GeoCOM supports two (three) kinds of usage. We
can distinguish between a rather rudimentary ASCII protocol and a high level
function call interface.
The former - ASCII protocol - is made up of requests and replies. Using GeoCOM
in this way means that an application assembles a request, sends it over the serial
line to the listening TPS1100 instrument, wait for the answer and decode the
received reply.
The latter uses normal function calls either in C/C++ or in VBA. For explanation
purposes we will split it into two categories because the two supported
programming environments differ in relation to their type systems. Using
GeoCOM in this way means calling a function. Any necessary communication
will be handled by GeoCOM implicitly.
2.1

GENERAL CONCEPT OF OPERATION

Fundamentally, GeoCOM is implemented as a point to point communication
system. The two communication participants are known as the client (external
device) and the server (TPS1100 instrument). One communication unit consists of
a request and a corresponding reply. Hence, one communication takes place when
the client sends a request to the server and the server sends a reply back to the
client.
request
Client Server
reply
Picture 2-1: Basic communication
GeoCOM is implemented as synchronous communication. A request/reply pair
may no be interrupted by another request/reply. Instead, a communication unit
must be completed successfully before a new communication unit may be
initiated.
TPS1100 - Version 1.05 2-1