Touchpoint 4 Serial Communication Protocol Issue 1 09/07
Glossary
The following terms are used in this manual:
Handshake:
The process of acknowledging a communication has been received.
The Touchpoint4 gas detector controller uses ACK/NAK responses.
Hexadecimal:
A type of numbering system with a base of 16. In this numerical system,
the letters A through F represents numbers 10 through 15 respectively. For example,
3F in hexadecimal represents 63 in decimal. The shortened version of the word
hexadecimal is generally "Hex", as in "Hex 3F." "0x" is the notation used in this manual
for hexadecimal (e.g. 0x3F).
Instrument:
This term is used to refer to the Touchpoint4 gas detector controller.
Master:
A computer or PLC that communicates with slaves using the
Touchpoint4 protocol.
Packet:
A block of information that is passed between the master and the slave.
A packet is made from many bytes of information.
Protocol:
The manner in which data is transferred and the format used for the transfer.
Touchpoint4 protocol refers to the packets of transferred data the Touchpoint4
instrument recognizes.
Slave:
Touchpoint4 gas detector controller. A network may have several slaves.
Time-Out:
The maximum amount of time allowed between the time the last byte of a
packet is sent from the “master” device to the time the “slave” device responds.
The time-out period of 1 second is recommended for this protocol. In fact, the period
from request transmission to response reception is not more than 500ms.
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