2626
COUNTER C SLAVE COMMUNICATIONS
Counter C may be programmed for , to act as a serial slave display. By
doing this, the carriage return <CR> is added as a valid command terminator
character for all serial command strings. The <CR> as a terminator may be very
useful for standard serial commands, even if Counter C is never displayed or
sent a slave message. The $ terminator should not be used in the slave mode. If
numeric values are not to be saved to memory, then send the value as a literal
transmission with <CR> terminator.
The Counter C slave display is right aligned. It has a capacity of displaying
six characters. When less than six characters are received, blank spaces will be
placed in front of the characters. If more than six characters are sent, then only
the last six are displayed. The meter has a 192 character buffer for the slave
display. If more than 192 characters are sent, the additional characters are
discarded until a terminator is received. Counter C processes numeric and literal
transmissions differently.
Numeric Transmissions
When a string that does not begin with #, T, V, P or R is received, the meter
processes it as a Numeric transmission. In this case, only the recognized
numbers and punctuation are displayed. All other characters in the string are
discarded. If a negative sign appears anywhere in the string the resulting number
will be negative. Only the most significant decimal point is retained. If no
numerical characters are received, then the numeric value will be zero. The
numeric display can be used for setpoint (boundary action only) and analog
output functions. When using this display for setpoint and analog output values,
the decimal point position must match the programming entered through the
front panel. The numeric value is retained in Counter C memory until another
Numeric transmission is received.
Recognized Numbers = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Recognized Punctuation = period, comma, minus
Literal Transmissions
When a string that begins with # is received, the meter processes it as a Literal
transmission. In this case, any unrecognized characters will be replaced with a
space. A Literal display will replace a Numeric value in the Counter C display.
However, it will not remove a previous Numeric value from Counter C memory
or prevent the Counter C outputs from functioning with the Numeric value.
Literal transmissions are only possible when using RS232 or RS485 cards.
Recognized Characters = a, b, c, d, e, f, g, h, i, j, l, n, o, p, q, r, s, t, u,
y, z (in upper or lower case)
Recognized Numbers = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Recognized Punctuation = period, comma, minus, blank
RECEIVING DATA FROM THE METER
Data is transmitted by the meter in response to either a transmit command (T),
a print block command (P) or User Function print request. The response from
the meter is either a full field transmission or an abbreviated transmission. The
meter response mode is established in Module 7.
Full Field Transmission (Address, Mnemonic, Numeric data)
Byte Description
1, 2 2 byte Node (meter) Address field [00-99]
3 <SP> (Space)
4-6 3 byte Register Mnemonic field
7-18 12 byte data field, 10 bytes for number, one byte for sign, one byte for
decimal point
19 <CR> carriage return
20 <LF> line feed
21 <SP>* (Space)
22 <CR>* carriage return
23 <LF>* line feed
* These characters only appear in the last line of a block print.
The first two characters transmitted (bytes 1 and 2) are the unit address. If the
address assigned is 00, two spaces are substituted. A space (byte 3) follows the
unit address field. The next three characters (bytes 4 to 6) are the register
mnemonic. The numeric data is transmitted next.
The numeric field (bytes 7 to 18) is 12 characters long. When the requested
value exceeds eight digits for count values or five digits for rate values, an *
(used as an overflow character) replaces the space in byte 7. Byte 8 is always a
space. The remaining ten positions of this field (bytes 9 to 18) consist of a minus
sign (for negative values), a floating decimal point (if applicable), and eight
positions for the requested value. The data within bytes 9 to 18 is right-aligned
with leading spaces for any unfilled positions.
The end of the response string is terminated with <CR> (byte 19), and <LF>
(byte 20). When a block print is finished, an extra <SP> (byte 21), <CR> (byte
22), and <LF> (byte 23) are used to provide separation between the transmissions.
Abbreviated Transmission (Numeric data only)
Byte Description
1-12 12 byte data field, 10 bytes for number, one byte for sign, one byte for
decimal point
13 <CR> carriage return
14 <LF> line feed
15 <SP>* (Space)
16 <CR>* carriage return
17 <LF>* line feed
* These characters only appear in the last line of a block print.
Meter Response Examples:
1. Address = 17, full field response, Count A = 875
17 CTA 875 <CR><LF>
2. Address = 0, full field response, Setpoint 2 = -250.5
SP2 -250.5<CR><LF>
3. Address = 0, abbreviated response, Setpoint 2 = 250, last line of block print
250<CR><LF><SP><CR><LF>
AUTO/MANUAL MODE REGISTER (MMR) ID: U
This register sets the controlling mode for the outputs. In Auto Mode (0) the
meter controls the setpoint and analog output. In Manual Mode (1) the outputs
are defined by the registers SOR and AOR. When transferring from auto mode
to manual mode, the meter holds the last output value (until the register is
changed by a write). Each output may be independently changed to auto or
manual. In a write command string (VU), any character besides 0 or 1 in a field
will not change the corresponding output mode.
U abcde
e = Analog Output
d = SP4
c = SP3
b = SP2
a = SP1
Example: VU00011* places SP4 and Analog in manual.
ANALOG OUTPUT REGISTER (AOR) ID: W
This register stores the present signal value of the analog output. The range
of values of this register is 0 to 4095, which corresponds to the analog output
range per the following chart:
Register
Value
Output Signal*
0-20 mA 4-20 mA 0-10 V
0 0.00 4.00 0.000
1 0.005 4.004 0.0025
2047 10.000 12.000 5.000
4094 19.995 19.996 9.9975
4095 20.000 20.000 10.000
Writing to this register (VW) while the analog output is in the Manual Mode
causes the output signal level to update immediately to the value sent. While in
the Automatic Mode, this register may be written to, but it has no effect until the
analog output is placed in the manual mode. When in the Automatic Mode, the
meter controls the analog output signal level. Reading from this register (TW)
will show the present value of the analog output signal.
Example: VW2047* will result in an output of 10.000 mA, 12.000 mA or
5.000V depending on the range selected.
SETPOINT OUTPUT REGISTER (SOR) ID: X
This register stores the states of the setpoint outputs. Reading from this
register (TX) will show the present state of all the setpoint outputs. A “0” in the
setpoint location means the output is off and a “1” means the output is on.
X abcd
d = SP4
c = SP3
b = SP2
a = SP1
In Automatic Mode, the meter controls the setpoint output state. In Manual
Mode, writing to this register (VX) will change the output state. Sending any
character besides 0 or 1 in a field or if the corresponding output was not first in
manual mode, the corresponding output value will not change. (It is not
necessary to send least significant 0s.)
Example: VX10* will result in output 1 on and output 2 off.
*Due to the absolute accuracy rating
and resolution of the output card, the
actual output signal may differ 0.15%
FS from the table values. The output
signal corresponds to the range selected
(0-20 mA, 4-20 mA or 0-10 V).
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