UMAX180800, 20 Thermocouple, 2 RTD, 4 Inputs, 6 Relays Dual CAN Controller
Version 1
Page: 20-71
3.3.4.1 Special Conditions
Frequencies below the Minimum Frequency value will be measured as zero and frequencies
above the Maximum Frequency value will saturate at the Maximum Frequency value for the
Frequency Range
Table 11. Maximum, Minimum Frequencies and Maximum Recovery Time for Universal Inputs
Frequency
Range
Counter
Minimum
Frequency
Maximum Frequency
Maximum Recovery
Time
1Hz…10kHz
16-Bit
0.9155Hz
12.5kHz
10.9ms
Frequencies above the Maximum Frequency value will switch the input to the Recovery state.
The input will stay in the Recovery state until the upcoming counter saturation event when the
frequency will be measured again. The input will leave the Recovery state if the measured
frequency value is below the Maximum Frequency.
Table 12. Frequency and PWM Measurements for Universal Inputs. Special Conditions
Input Mode
Signal Frequency (
𝐹
𝑠
)
𝐹
𝑠
= 0
Zero Frequency
(DC)
0 < 𝐹
𝑠
< 𝐹
𝑚𝑖𝑛
Below Minimum
Frequency
𝐹
𝑚𝑖𝑛
𝐹
𝑚𝑖𝑛
≤ 𝐹
𝑠
≤ 𝐹
𝑚𝑎𝑥
Working Frequency
𝐹
𝑠
> 𝐹
𝑚𝑎𝑥
Above Maximum
Frequency
𝐹
𝑚𝑎𝑥
Measured
Frequency
𝐹
𝑚
𝐹
𝑚
= 0
𝐹
𝑚
= 0
𝐹
𝑚
= 𝐹
𝑠
𝐹
𝑚
= 𝐹
𝑚𝑎𝑥
Recovery state
Measured PWM
Duty Cycle
𝐷
𝑚
𝐷
𝑚
= {0, 100}
Undefined (not
allowed)
𝐷
𝑚
= 𝐷
𝑠
,
𝐷
𝑠
– signal duty cycle
𝐷
𝑚
= 0
Recovery state
The time between two consequent counter saturation events defines the Maximum Recovery
Time, see Table 11
Error! Reference source not found.
. This time is the maximum transient t
ime when the measured frequency will stay equal to the Maximum Frequency value.
When the PWM signal is absent, the duty cycle is measured as 0 or 100% based on the
voltage level on the input and the selected
Input Polarity
. The voltage level is sampled on the
counter saturation events until the PWM signal is back on the input.
The transient time between the PWM signal duty cycle and the duty cycle of the DC level when
the signal disappears can be up to the Maximum Recovery Time. During the transient time, the
measured value will stay equal to the last measured value of the PWM signal duty cycle.
The PWM input signal with a frequency above zero but below the Minimum Frequency value is
not allowed. The duty cycle will not be measured, instead, it will be jumping between 0% and
100% depending on the voltage level at the input on the counter saturation events.
When the PWM input signal frequency exceeds the Maximum Frequency value, the input goes
into the Recovery state and the PWM duty cycle is measured as 0%. Similar to frequency
measurements, the input will stay in the Recovery state for up to the Maximum Recovery Time
before the duty cycle is measured again.
3.3.5 Diagnostics
The ECU has a diagnostic option for Measuring Out of Limits Faults: for low limit and high limit.
The default values can be found in the Section 4.3.3. Disregarding the parameter set in the
