Interface 9834 Instruction Manual - page 20
Page 17
SERIAL RS232 COMMUNICATIONS
General Information
See Figure 4 on page 4 for RS232 connections and wiring information.
See Figure 5 on page 5 for setting baud rate. The unit is pre-wired for 9600 baud.
The data is transmitted in the following format:
One Start Bit;
Eight Data Bits;
No Parity Bit;
One Stop Bit
Transmissions from the Model 9834 are controlled by sending XOFF (ASCII code decimal 19,
DC3) to suspend character transmission and XON (ASCII code decimal 17, DC1) to start
transmission. All transmissions to the Model 9830, including XON and XOFF, must terminate
with a CR (hex OD) and only a CR.
Note: do not send a line feed.
The RS232 port is active only in the data display mode and will not respond in while in the
MODE sequence.
RS232 Programming Data
The RS232 data is transmitted in 8 sequential bytes, in binary or bit significant format,
depending on the parameter. The data has the following significance.
Byte
Description
1
Status Byte: Setpoint Status
The status is contained in one byte and is bit significant
A logical 1 indicates setpoint value exceeded.
Bit
Status of
Bit
Status of
0
SP1
4
Not Used
1
SP2
5
Not Used
2
SP3
6
Not Used
3
SP4
7
Not Used
2
Function Byte: ID of transmitted function
Value
Function
1
Instantaneous
8
Peak minus Valley
65
Peak
66
Valley
3-6
Data Byte: Binary representation of data.
The data value is represented in 2's complement where bytes 3 is
the most significant byte and byte 6 is the least significant byte.
7
Decimal Point Byte:
The decimal is represented as an exponent
The value for x.xxxx is 1
The value for xx.xxx is 2
The value for xxx.xx is 3
The value for xxxx.x is 4
The value for xxxxx is 5
8
EOT Byte: This byte indicates end of transmission - transmitted as hex OA.