General errors
Mapping of the digital and the byte-oriented Bus Terminals onto a fixed address
- Problem
You want a constant start address for the digital inputs and outputs. - Solution
With the KS2000 software, you can enter an offset start value for the digital inputs and outputs in table 0. The byte-oriented Bus Terminals should not jut into this process image, i.e. no overlap should occur. Table 0: Register 19 Offset for digital outputs, Register 20 Offset for digital inputs: "0" is the default setting (automatic Bus Terminal mapping) - Example
You have a KL3002 and a KL2012. In the default case, the KL3002 maps onto %IB0- %IB7 and %QB0-QB7 in the memory. The digital output terminal would now map to %QX8.0 and %QX8.1. As soon as you now plug another byte-oriented Bus Terminal, the process image of the digital Bus Terminal is moved to a higher memory. You can now pre-empt this by entering 20 in register 19. This means that KL2012 now maps onto %QX20.0 and %QX20.1.
Drop of the digital outputs
- Problem
Your digital outputs drop away. - Solution
Your program takes longer than 100 ms. Because the internal K-Bus runs synchronous with your PLC program, it is no longer triggered early enough, and the Bus Terminal watchdog becomes active. This can be rectified by triggering a short refresh of the K-Bus. The setting can be carried out with the KS2000 software. Table 1 Register 17 LowByte cycle time for K-Bus refresh (<= 80 ms) HighByte Retries - Recommendation
Enter 0x0350 in Table 1 Register 17. This means three retries, once every 80 ms. Note that this causes the Bus Terminal watchdog to increase to 240 ms during a fault condition (this is not true in case of a K-Bus error, where the watchdog will remain at 100 ms).