Serial communications, Modbus scanner process variables, Math channels – Precision Digital PD6730X User Manual
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PD6730X Vantageview Super Snooper Modbus Scanner
Instruction Manual
10
Serial Communications
PROTOCOL
3-Wire RS-485 Modbus® RTU
SCANNER ID
1 – 247. Specifies the address of the PD6730X.
BAUD RATE
1,200; 4,800; 9,600; 19,200; 38,400; 57,600; or 115,200 bps
TRANSMIT TIME
DELAY
Programmable between 0 and 199 ms
PARITY/STOP BIT
Even, odd, none with 1 stop bit, or none with 2 stop bits
BYTE-TO-BYTE
TIMEOUT
Max of 1.5 character times or 750 μs
Modbus Scanner Process Variables
PV INPUTS
Up to 16 independently programmed Modbus process variables (PVs) may be
scanned (Master mode) or detected (Snooper mode). Each of the 16 Modbus
PVs may be enabled or disabled.
SLAVE ID
Specifies which device on the bus to monitor. Valid for Master and Snooper
modes only.
Assign the slave ID or address (1-247) of each of the devices containing the
process variables to be displayed (Slave ID for PV1-16).
REGISTER NUMBER
Specifies which register(s) to read in the devices on the bus.
5 Digit Function 03: 40001–49999; 04: 30001–39999; or 65: 1–9999.
6 Digit Function 03: 400001–465535 or 04: 300001–365535; or 65: 1–65535.
Range is dependent on Function Code selection (03, 04, or 65)
Will read 2 registers for Long integer and Floating point data types; the register
entered and the next consecutive register number.
Valid for Master and Snooper modes only.
FUNCTION CODE
03, 04, and 65 (used to read 32 bit registers). Master & Snooper modes only.
DATA TYPE
Select the data format of the PVs. Select between short integer (2 byte), long
integer (4 byte), or floating point (4 byte). Slave mode uses floating point only.
BYTE
ORDER
Integer data programmable as binary or BCD, and signed or unsigned. Byte
order selectable as big-endian (1234), little-endian (4321), byte swap big-endian
(2143), or byte swap little-endian (3412). Byte swap unavailable for short.
Math Channels
MATH RESULT
CHANELS
Four math channels CV1-CV4. Each math channel may be programmed for a
math function.
MATH FUNCTIONS
Parameter 1 (PAR1), parameter 2 (PAR2), and parameter 3 (PAR3) independently programmable for
each math channel C1-C4.
Math Function
Function
Setting
Addition
PAR1 + PAR2
SUM
Difference PAR1
-
PAR2
DIF
Multiplication
PAR1 * PAR2
MULTI
Division
PAR1 / PAR2
DIVIDE
Absolute diff.
Abs(PAR1 - PAR2)
DIFABS
Weighted avg.
((PAR1 – PAR2)*PAR3) +PAR2
WAVG
Draw
((PAR1 / PAR2) – 1) * PAR3
DRAW
Ratio
(PAR1 / PAR2) * PAR3
RATIO
Concentration
PAR1 / (PAR1 + PAR2) * PAR3
CONCEN
Contant Constant
CONST
Long Integer
Constant
LONG
Floating Pt.
Constant
FLOAT
None Disable
NONE
Absolute Value
Abs(PAR1)
ABS
Square Root
√(PAR1)
SQrt