Campbell Scientific CR1000KD CR800 and CR850 Measurement and Control Systems - Page 354

Section 8. Operation 8.6.2.5 Modbus over IP Modbus over IP functionality is an option with the CR800. Contact Campbell Scientific for details. 8.6.2.6 Modbus tidBytes 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(). Concatenating two Modbus long 16‐bit variables to one Modbus long 32 bit number. 8.6.2.7 Converting 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. CRBasic Example 66. Concatenating Modbus Long Variables 'Requires CR800 OS v.3, CR1000 OS v.12, or CR3000 OS v.5 or higher 'CR800 uses Big-endien word order. 'Declarations Public Combo As Long Public Register(2) As Long Public Result 'Variable to hold the combined 32-bit 'Array holds two 16-bit ModBus long 'variables 'Register(1) = Least Significant Word 'Register(2) = Most Significant Word 'Holds the result of the ModBus master 'query 'Aliases used for clarification Alias Register(1) = Register_LSW Alias Register(2) = Register_MSW 'Least significant word. 'Most significant word. BeginProg 'If you use the numbers below (un-comment them first) 'Combo is read as 131073 decimal 'Register_LSW=&h0001 'Least significant word. 'Register_MSW=&h0002 ' Most significant word. 354