Specifications

Section 12. Serial Input and Output Functions
12-5
Parameter
& Data Type
Enter
Variable
Variable
The variable array that is used as the source of data to send to the
ModBusSlave, or the variable array that is used as the destination for data
received from the ModBusSlave.
Start
Integer or
constant
The first coil or register that will be acted upon with this instruction. Coil
numbering starts at 1, and the coils are mapped to control ports 1 through
8. Registers are specified as the desired Start Register/2+1.
Length
Integer or
constant
The number of coils or registers to act upon with this instruction (e.g., if
reading the status of control ports 1, 2, 3, and 4, you would specify a Start
of 1 and a Length of 4).
Tries
Integer or
constant
The number of times the ModBusMaster datalogger should attempt to
communicate with the SlaveModBus datalogger before moving on to the
next instruction.
TimeOut
Constant or
variable
The amount of time, in 0.01 seconds, that the ModBusMaster datalogger
should wait for a response from the ModBusSlave before considering the
attempt a failure.
ModBusSlave (ComPort, BaudRate, ModBusAddr, ModBusVariable,
BooleanVariable)
The ModBusSlave instruction sets up a datalogger as a ModBus slave device.
Syntax
ModBusSlave ( ComPort, BaudRate, ModBusAddr, ModBusVariable,
BooleanVariable)
Remarks
This instruction sets up a ModBus slave device to respond to the data request
of a ModBus master. Supported ModBus functions are 01, 02, 03, 04, 05, 15,
and 16. See the ModBusMaster for details on these functions.
Parameter
& Data Type
Enter
Specifies the communication port and mode that will be used when
sending the dial string. If a negative code is entered for the ComPort
(e.g., -1), the datalogger will not wait for successful communication
before moving on to the next instruction.
Numeric
Code
Alpha
Code
Description
0 ModBus
/PakBus
ModBus packets routed via PakBus
1 ComRS232 RS232 port of the datalogger
2 ComME Datalogger's CS I/O port; modem enabled
3 Com310 Datalogger's CS I/O port; COM 310 modem
4 ComSDC7 Datalogger's CS I/O port; SDC7
5 ComSDC8 Datalogger's CS I/O port; SDC8
6 Com1 Datalogger's control ports 1 (TX) & 2 (RX)
7 Com2 Datalogger's control ports 3 (TX) & 4 (RX)
8 Com3 Datalogger's control ports 5 (TX) & 6 (RX)
ComPort
Constant
9 Com4 Datalogger's control ports 7 (TX) & 8 (RX)