CSZ ZP 16, Installation, Operation & Maintenance Manual, Page: 57 / 88

OPERATION
Page 4-9
IEEE 488 - F4 CONTROLLER
The ICS GPIB to Serial Converter is used to convert the information on the GPIB
bus into serial data to communicate with the F4. The F4 is set to use its RS-232
interface with the ICS converter. The F4 and converter are set up at the factory. The
F4 settings are the default values for the serial interface. The ICS converter settings
have been modi
fi ed from their default values as listed below to interface with the F4.
F4 Settings: ICS Converter Settings:
Address 1 SYST:MODE G
Baud Rate 9600 STAT:QUES:ENAB 0
SYST:COMM:SER:EOI 0
STAT:OPER:ENAB 512
*SRE 128
The converter address is set to four (4). For a more detailed explanation on the
ICS converter settings and how to change the address, see Section 3, " Operating
from the GPIB Bus", of the IEEE manual located in the Accessories folder on the
digital media.
SENDING/RECEIVING DATA
The F4 uses Modbus protocol for its communications. This requires all data being
sent to, and all data being received from, the F4 will be hexadecimal characters
formatted into packets. It is recommended that the user become familiar with
this format before any attempt is made to communicate with the F4. Watlow
provides a very useful and well-documented manual on how to perform Modbus
communications with the F4. This manual is available on Watlow’s web site and
is called the Data Communications Reference Electronic User’s Manual. The
manual explains how to format the data strings, what commands are available,
and how to create subroutines to generate checksums.
The commands and format used to communicate over the GPIB bus will be
identical to that explained in the manual. The only difference will be that a line
feed (LF) terminator will have to be appended to the data string when it is sent so
the GPIB converter can sense the end of the message. The data will be sent to
the F4 which will then send a response back to the converter. When addressed
to talk, the converter will send the data string from the F4 with a line feed (LF)
terminator appended to it.
Example:
Read Register 0 (model number) of controller at address 0:
Send: 010300000001840A
Received: 01030203DCB92D
NOTE: All data is in HEX format. The bus controller must address device
number four (4), the GPIB converter, when sending and receiving the data. Line
feed terminators are used to signal end of transmission; however, it is necessary
for the bus controller to transmit the number of bytes to be read when addressing
the converter to talk. In the above example, the byte count would be seven (7).
Since the F4 transmits and
receives binary data, it is not
possible for the converter to
sense the end of the F4’s
message since a EOM
character could be part of
the message. Therefore,
it is necessary to set the
number of bytes to be read
from the converter when it is
addressed to talk. Since the
packet structure is
fi xed, the
number of bytes will remain
a set value.
NOTE