RS-232 OPTION

INSTALLING THE RS-232 OPTION BOARD

Install the RS-232 option board as follows (refer to Figure 8-1):

Caution: the meter has no power-on switch, so it will be in operation as soon as you apply power.

Important: Disconnect the power from the unit before installing this option board.

1. Remove the protective back panel and slide the meter out of the case.
2. Hold the RS-232 option card in a vertical position, with the J2 connector facing the back of the meter.
3. Line up the P1 connector on the RS-232 board with the J1 pins on the main board. Push down to secure.
RS-232 Option Board
Figure 8-1. Installing the RS-232 Option Board

Protective Back Panel
Figure 8-2. Protective Back Panel

4. Slide meter back into the case.
5. Install the protective rear panel to secure the board (refer to Figure 8-2):
    a. Align the two bottom front edges of the protective panel with the corresponding groves on the meter case.
    b. Align the top left groove of the protective panel with the RS-232 board.
    c. Snap protective panel closed.
REMOTE PROGRAMMING
The meter may accept an RS-232 card for communications. The card enables the meter to receive setup commands and data, and send measurement values and current setup data to a computer. The meter operates at either 1200 or 9600 baud, 7 data bits, even parity and 1 stop bit. It emulates DCE (data communication equipment) and uses a handshake line while sending data, but none while receiving data. A 4-wire cable is the maximum required for the following communications:


When you connect your meter to a computer, such as an IBM PC, and the meter receives one of 8 commands (P, G, W, R, V, SC, SG and SP) the meter interrupts its program, receives the message, takes appropriate action, and then starts over with a new measurement. No handshake is required because the meter devotes its full attention to receiving the command data from the computer. In the other direction, the meter sends measurement and confirming setup data to the computer under one of 2 handshake (RTS) modes.

Message Handshake - The RTS line is checked when the device is ready to send measurement data. If the RTS is true, it sends the complete message data without interruption even if the RTS goes false in the middle of transmission. If the RTS is false, it skips sending the data completely and continues with the next measurement.

Character Handshake - The device checks the RTS input before sending each character and sends characters only while the RTS is true.

ASCII OUTPUT
The meter sends measurement data according to the following fixed formats of 9 or 8 characters. Each character is sent as a 7-bit ASCII code character with even parity, and may be blank (ASCII 32)


9-Character Format

Figure 8-3. ASCII Output 9-Character Message (COnFIG=XXXXX0)

As Figure 8-3 details, the 1st character represents alarm information and provides one of the following: H = High Alarm, L = Low Alarm, B = Both High and Low Alarms or Space = Neither High nor Low Alarms.

Characters 1 through 8 represent the measurement value as shown on the front-panel. If positive, there are 6 digits and a decimal point; if negative, there is a minus sign with 5 digits and a decimal point. Blanks are sent in place of leading zeros. If the value overflows the 6-digit limit, it is sent in exponential format up to a maximum of 9.99 E9 or -9.9 E9. The final character is a carriage return.

8-Character Format
ASCII Output
Figure 8-4. ASCII Output 8-Character (COnFIG=XXXXX1)

Characters 1 through 7 represent the value on the display (6 digits and a decimal point). The final character, (character 8), is a carriage return.

SETUP DATA
'Get' or 'Read' commands send setup data to the computer for verification. Setup data is sent and received as ASCII characters representing the 16 hex characters 0-9; A-F. Each hex character represents 4 bits or 16 pieces of information. The 7-bit ASCII characters are shown with a leading even-parity bit, as shown in Table 8-1.


Hex Character/Bit Pattern Information Table 8-1
Hex Character
Bit Pattern
Hex Character
Bit Pattern
0
0011 0000
8
1011 1000
1
1011 0001
9
0011 1001
2
1011 0010
A
0100 0001
3
0011 0011
B
0100 0010
4
1011 0100
C
1100 0011
5
0011 0101
D
0100 0100
6
0011 0110
E
1100 0101
7
1011 0111
F
1100 0110

The setup data consists of a total of 44 nibbles of information that are sent and received in the following order:
Setup Order Information Table 8-2
Display
Parameter
# of Nibbles
-------
Analog Out Scale*
2
Analog Out Offset*
4
Calibration
2
SP HI
Setpoint High
6
SP LO
Setpoint Low
6
OFFSEt
Offset
6
SCALE
Scale
6
-------
Gate Time and Time Out
4
-------
Analog Output Control*
2
COnFIG
Configuration
2
dEC Pt
Decimal Point
2
Func
Function
2
* Do not confuse with "An LO" and "An HI".

Each parameter is sent with the most-significant nibble first. Each bit may have stand-alone significance or may be part of a binary number according to the following formats. The binary value 0-255 is used to calculate the analog output value from the display value (refer to Figure 8-9). See also Control Bit Storage (refer to Figure 8-7).

Analog Out Scale (2 Nibbles Each)

Figure 8-5
Analog Out Scale Storage Format
Analog Out Offset (4 Nibbles Each)

Figure 8-6
Analog Out Offset Storage Format

NOTE: 256 generates 0 V (0 mA) and 51200 generates 10 V (20 mA).

ANALOG OUT CONTROLS
An LO and An HI menu items are for coarse adjustment of analog output. The meter uses these values to calculate Analog Scale and Offset. Analog Scale is one byte and stored in location 3E. Analog Offset is 2 bytes and is stored in locations 3C and 3D. Location 2C is used for storage of control bits as follows:


Figure 8-7. Storage Format
The decimal point value must be 1 through 6 (not 0 or 7).
Example: A01000 = -0409.6 DP=2, - Negative Polarity

GATE TIME
Gate Time

Figure 8-8. Binary Value

Figure 8-9. Setup Configuration
If MS byte is 1111 1111, meter uses 00000000.


Figure 8-10. Decimal Point Setup


Figure 8-11. Totalizer Function Setup

One, and only one bit must be a 1 - except for the totalizer bit, which may also have the zero total bit set to a 1. When the meter receives the totalizer bit, the zero total bit causes the value to be reset to zero; otherwise, the TOTALIZER value is unaffected.

  Help Price List Specifications Print Manual Manuals Home
 Home Home
 Table of Contents TOC  Back Back  Next Next