VDH MC3-SC, Manual, Page: 35 / 45

MC3-SC Stepped Controller
Document no.: 140744 version 1.3
Page 35 of 45
7.3 Overview of the functional flow for a compressor with 5 cylinders
7.4 How regulation works for a compressor with unequal steps
A maximum of 1000 regulating steps can be made. If the number of steps is exceeded, error
message ‘E 80’ is displayed. The controller then regulates using the steps calculated until that
point. It is also possible to use compressors with a valve lift. The number of steps can be calculated
as follows: (#steps-comp. 1) * (#steps-comp. 2) etc.
Example 1: Comp. 1: 3 cylinders (0-33-66-100% = 4 steps), e.g. 1kW
Comp. 2: 2 cylinders (0-50-100% = 3 steps) e.g. 2kW
giving 4 * 3 = 12 steps.
Example 2: Comp. 1: 2 cylinders (0-50-100% = 3 steps)
Comp. 2, 3, 4, 5: (0-100% = 2 steps)
giving 3 * 2 * 2 * 2 * 2 = 48 steps