Micromod MOD: 1800P - MOD 30ML Identity Module (Version 2) System, I/O and Communications Functions - Manual (Page 246)

Logic Functions - Book 1
APPENDIX B - MODBUS MASTER CONFIGURATION
B-2
B.2 MODCELL SERIAL COMMUNICATION (MSC) BLOCK MODIFICATIONS
Configure an MSC block to be used as a MASTER. If the MSC block is version 2, just
configure the Port Functionality attribute to be Master using the Application Builder or ViZapp
Port Functionality configuration entry. This can also be done by writing the value 251 to the
MSC Command attribute from the status page after the database is downloaded into the
instrument (MSCx,CMD 251). This will allow the initialization required for the MSC block to be
a MASTER. To return the MSC block to a SLAVE simply write the value 252 to the MSC
Command attribute (MSCx,CMD 252). This will allow the initialization required for the MSC
block to be a SLAVE. These procedures only need to be done one time. Since a port can
easily be changed between MASTER and SLAVE you could have your logic configuration
transfer master control between multiple Modcell Multiloop Processors. When the MSC block
is a MASTER the List items in the MSC block are ignored.
B.3 EXPRESSION (EX) BLOCK MODIFICATIONS
Expression blocks can be configured to read data from Modbus Slave devices or write data to
Modbus Slave devices. This is done by configuring the EX block INPUT1 as an ASCII string
(UPPER CASE LETTERS) as follows:
CFG,MM,PORTz Modbus Master EX block used for configuration items. There must
be one of these blocks configured for each port used as a modbus master. See
section B.3.1
RCS,MM,PORTz Modbus Master EX block used to read the Coil Status (Discrete
Read/Write memory) area 00001 to 09999. See section B.3.2
RIS,MM,PORTz Modbus Master EX block used to read the Input Status (Discrete
Read Only memory) area 10001 to 19999. See section B.3.3
RIR,MM,PORTz Modbus Master EX block used to read the Input Register (Read Only
memory) area 30001 to 39999. See section B.3.4
RHR,MM,PORTz Modbus Master EX block used to read the Holding Register
(Read/Write memory) area 40001 to 49999. See section B.3.5
WRC,MM,PORTz Modbus Master EX block used to write one or more Coils
(Discretes) in memory area 00001 to 09999. See section B.3.6
WRR,MM,PORTz Modbus Master EX block used to write one or more Registers
(attributes) in memory area 40001 to 49999. See section B.3.7
Where z indicates which MSC port the EX block is associated with.
The value 1 indicates MSC1 which is connected to serial port 1.
The value 2 indicates MSC2 which is connected to serial port 2.
The value 3 indicates MSC3 which is connected to serial port 3.
The BAD INPUTS ACCEPTED attribute in the EX block is used as follows:
NO If the quality of any INPUT LSP used by the EX modbus master is bad, the
message will not be sent.
YES INPUT LSP qualities are not checked.