Quantum message request gives incorrect values.
Goals and Symptoms
Quantum message request gives incorrect values.
Causes and Fixes
When requesting a register value from a quantum device, the response returns the value from the next addressed value, while making the same request to a Premium or M340 device the address is correct.
This stems from the different historical method of counting for the different families of PLCs. In quantum the registers begin counting at 1 (one). Thus 40001 would be the first register and there would be no 40000 register. In Premium and M340 the first register begins at 0 (zero). Unity uses IEE standards and thus %MW0 – the first memory word would be 40001 in the Quantum. In order to request a register and receive the proper addressed response The 4x register should be decremented by 1. %MW0 = 40001, %MW98 = 40099. The decremented value should be used in all communication to any Quantum PLC.
Quantum message request gives incorrect values.
Causes and Fixes
When requesting a register value from a quantum device, the response returns the value from the next addressed value, while making the same request to a Premium or M340 device the address is correct.
This stems from the different historical method of counting for the different families of PLCs. In quantum the registers begin counting at 1 (one). Thus 40001 would be the first register and there would be no 40000 register. In Premium and M340 the first register begins at 0 (zero). Unity uses IEE standards and thus %MW0 – the first memory word would be 40001 in the Quantum. In order to request a register and receive the proper addressed response The 4x register should be decremented by 1. %MW0 = 40001, %MW98 = 40099. The decremented value should be used in all communication to any Quantum PLC.