Red Lion GEMINI 52 - Manual (Page 26)

SENDING COMMANDS & DATA TO THE GEMINI 5200
When sending commands to the Gemini 5200, a command string must be
constructed. The command string may consist of command codes, value
identifiers, and numerical data. Below is a list of commands and value identifiers
that are used when communicating with the Gemini 5200
COMMAND DESCRIPTION
N (4EH) Address command; followed by a unit address number 1-15
and one of the following commands.
P (50H) Transmit per Print Options command.
R (52H) Reset command; operates on Output(s) assigned to
the channel being reset.
T (54H) Transmit Value command; operates on display values,
Presets and Scale Factors.
V (56H) Change Value command; operates on Scale Factors,
and Presets.
D (44H) Change Display command; operates on display values (E -G).
VALUE IDENTIFIER DESCRIPTION MNEMONIC
A (41H) Preset 1 (PS1)
B (42H) Preset 2 (PS2)
C (43H) Scale Factor A (SFA)
D (44H) Scale Factor B (SFB)
E (45H) Rate A (CTA)
F (46H) Rate B (CTB)
G (47H) Display C (CTC)
The command string is constructed by using the above commands and value
identifiers, along with the data values that are required. Data values may or may
not contain the decimal point if a decimal point is programmed into the Gemini
5200. The Gemini 5200 will accept the decimal points, however, it does not
interpret them in any way. Leading zeros can be eliminated, however, all trailing
zeros must be present. For example, if a Scale Factor of 1.0000 is to be sent, the
data value can be transmitted as 1.0000 or 10000. If a “1” is transmitted, the Scale
Factor will be changed to 0.0001.
The Address command is used to allow a command to be directed to a specific
unit in the Serial Communications Loop. Whenever the unit address is zero,
transmission of the Address command is not required. This is done for
applications which do not require more than one Gemini. For applications that
require several units, it is recommended that each unit in the loop be given a
separate address. If they are given the same address, a command such as the
Transmit Value Command, will cause all the units to respond at the same time,
resulting in erroneous data.
The command string is constructed in a specific logical sequence. The Gemini
5200 will not accept command strings that do not follow this sequence. Only one
operation can be performed per command string. Below is the procedure to be
used when constructing a command string.
1. If the Gemini 5200, to which the command is to be sent, is assigned an address
other than zero, the first two characters of the command string must consist of
the Address Command (N) and the address number of the unit (1-15).
2. The next character/s in the command string is the actual command that the
Gemini 5200 is to perform and the value identifier if it pertains to the
command. (A command such as the Transmit per Print Options, “P”,
command does not require a Value Identifier.)
3. If the change command is being used, the next characters in the command
string is the numerical data value.
4. The last character in the command string is the command terminator (*). This
character must be sent in order to tell the Geminis that the command string is
complete, so that they can begin processing the command.
Below are some typical examples of properly constructed command strings.
(EX. 1) Change Preset 1 on the Gemini 5200 with address of 2 to 00123.4.
COMMAND STRING: N2VA1234*
(EX. 2) Have the Gemini 5200, with address of 3, transmit the Rate B value.
COMMAND STRING: N3TF*
(EX. 3) Reset the Rate B outputs of the Gemini 5200 with address of 0.
COMMAND STRING: RF*
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