Section 8. Operation
531
The following example demonstrates how to report data by Modbus but not allow
a Modbus client to change register or coil values in the Modbus host:
•
Var
can be viewed and changed
•
Reg()
and
Coil()
can only be viewed
•
The CRBasic program can read from and write to all variables
Public
Var
Public
Reg(4), Coil(4) as Boolean
ReadOnly
Reg, Coil
BeginProg
'setup modbus tcp/ip slave
'readonly instruction above makes reg and coil read only / not
writable
ModbusSlave
(502,0,1,Reg,Coil,2)
Scan
(5,Sec,0,0)
var = var + 1 ' increment var
MBReg() = MBReg() + 0.1
'increment all the registers
MBCoil() = (NOT MBCoil())
'toggle all the coils
NextScan
EndProg
8.10.3.6 Modbus Over RS-232 7/E/1
Q: Can Modbus be used over an RS-232 link, 7 data bits, even parity, one stop
bit?
A: Yes. Precede
ModBusMaster()
/
ModBusSlave()
with
SerialOpen()
and set
the numeric format of the COM port with any of the available formats, including
the option of 7 data bits, even parity.
SerialOpen()
and
ModBusMaster()
can
be used once and placed before
Scan()
.
8.10.3.7 Converting Modbus 16-Bit to 32-Bit Longs
Concatenation of two Modbus long 16-bit variables to one Modbus long 32
bit number is shown in the following example:
Содержание CR6 Series
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Страница 76: ...Section 5 Overview 76 FIGURE 20 Half Bridge Wiring Example Wind Vane Potentiometer ...
Страница 80: ...Section 5 Overview 80 FIGURE 23 Pulse Input Wiring Example Anemometer ...
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Страница 251: ...Section 7 Installation 251 FIGURE 46 Running Average Frequency Response FIGURE 47 Running Average Signal Attenuation ...
Страница 454: ...Section 8 Operation 454 FIGURE 104 Narrow Sweep High Noise ...
Страница 459: ...Section 8 Operation 459 FIGURE 106 Vibrating Wire Sensor Calibration Report ...
Страница 535: ...Section 8 Operation 535 8 11 2 Data Display FIGURE 121 CR1000KD Displaying Data ...
Страница 537: ...Section 8 Operation 537 FIGURE 123 CR1000KD Real Time Custom ...
Страница 538: ...Section 8 Operation 538 8 11 2 3 Final Storage Data FIGURE 124 CR1000KD Final Storage Data ...
Страница 539: ...Section 8 Operation 539 8 11 3 Run Stop Program FIGURE 125 CR1000KD Run Stop Program ...
Страница 541: ...Section 8 Operation 541 FIGURE 127 CR1000KD File Edit ...
Страница 542: ...Section 8 Operation 542 8 11 5 PCCard Memory Card Management FIGURE 128 CR1000KD PCCard Memory Card Management ...
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Страница 549: ...Section 9 Maintenance Details 549 FIGURE 133 Separate Back Shell from Module FIGURE 134 Disconnect Battery Connector ...
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Страница 610: ...Section 11 Glossary 610 FIGURE 137 Relationships of Accuracy Precision and Resolution ...
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