Cooper Instruments & Systems DFI INFINITY Digital Force Indicator/Controller - Manual (Page 15)

Table 4.2 Meter Receiving Voltages
OPTION TYPE
“1” BIT/MARK
OR STOP BIT “0” BIT/SPACE OR
START BIT
RS-232
RS-422 OR 485 -3 > A > -15 V
A< (B-0.2 V) +3 < A < +15 V
A > (B+0.2 V)
Table 4.3. Meter Transmitting Voltages
OPTION TYPE
“1” BIT/MARK
OR STOP BIT “0” BIT/SPACE OR
START BIT
RS-232
RS-422 or 485 -6 > A > -7 V
A < (B-2 V) +6 < A < +7 V
A > (B+2 V)
The RS-422/485 transmissions from the meter are 3-state, and both receive and transmit are zener-protected.
4.15 Recognition Character
A selectable symbol (e.g., the asterisk, *) transmitted as the first character of each message from the computer,
which is used for message security: the meter ignores messages without this symbol.
4.16 RAM
The acronym for “Random Access Memory”. For the meter, the storage for the data and instructions for the
immediately occurring operation. When given a “RESET1” or “soft” reset, the meter restarts its operation from
the data in RAM. “PUT” commands insert information from the computer into RAM, and “GET” commands
transmit RAM information to the computer.
4.17 EEPROM
The acronym for “Electrically Erasable Programmable Read-Only Memory”. For the meter, the non-volatile
memory for the setup and configuration data is retained independent of power or resets. Upon a “RESET2” or
“hard” reset (e.g., after any BLOCK WRITE command), the data in the EEPROM is copied into RAM, discarding
whatever data had been running. “WRITE” commands insert information from the computer into EEPROM, and
“READ” commands transmit EEPROM data to the computer.
5. BAUD RATES
The meter can operate at any rate from 300 to 19,200 in 2:1 steps. Following are the baud rates used by the
meter:
300, 600, 1200, 2400, 4800, 9600, and 19200.
6. CHARACTER WAVEFORM
Ten or eleven bits are used for each character: a start bit, 7 bits for the ASCII character, one parity bit, and
either one or two stop bits. If the parity bit is chosen as “none” (absent), the stop length is automatically set at
two bits by the meter (to keep the minimum character length to ten bits).
Figure 6-1 shows the mark/space sequence.
CF 125 INFINITY SC GUIDE 11 M1519/N/0605