The internal precision voltage measurement can be used to improve absolute value measurement accuracy.
This section describes Epec 4602 control unit's AI programming interface.
Value range 0 … 1023 (10bit)
The accuracy of the AD converter is 10 bits
Sample interval 1ms (nominal).
Asynchronous (AD converter's ring buffer values may change in the middle of the program cycle because it is not synchronized with the application cycle.)
MultiTool Creator creates derivative variables that do not change the values in the middle of the program cycle
Optional ring buffer for every channel (buffer and sample amount can be set with (IO_SET_AI_BUFFER (FB))
Related libraries:
AI library (AI_MeanValue (FUN), AI_V_to_DI (FB))
4602Specific (HWD_Measurements (FB))
4000Ext (IO_SET_AI_BUFFER (FB))
For %I interface addresses, refer to section PLCopen Addresses.
Last written value from ADC
Configuration bit for current mode (depending on the pin if available, current mode is selected when DO is true)
For %Q interface addresses, refer to section PLCopen Addresses.
Equation for voltage measurement:
U [V] = ADCvalue * (5 V / 1023)
ADCvalue = Last written value from ADC
To check the measurement accuracy, use internal precision voltage described below.
Equation for current measurement:
I [A] = ADCvalue * 5 V / (1023 * 220 Ohm)
ADCvalue = Last written value from ADC
This voltage reference can be used to check validity of the AD converter reference. If the measurement is out of the voltage nominal voltage range, analog measurements of the control unit might not be reliable.
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The internal precision voltage measurement can be used to improve absolute value measurement accuracy.
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Symbol |
Parameter |
Conditions |
Min |
Max |
Units |
|
UR2V5 |
Nominal 2,5V precision voltage level |
|
Typ. 2,5 |
V |
|
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2,4 |
2,6 |
V |
|||
|
Diagnostics |
Low |
High |
Units |
||
|
|
Recommended precision voltage warning levels |
|
2,4 |
2,6 |
V |
|
|
This product includes 2 additional internal voltages (3,6 V and 7,3 V) that should be monitored to ensure unit's correct operation.
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Equation for internal precision voltage measurement:
U [V] = ADCvalue * (5 V / 1023)
ADCvalue = Last written value from ADC
This product includes two additional internal voltages that can be monitored to ensure unit's correct operation:
3,6 V DI threshold voltage reference. If the voltage differs from the limit values, the DI measurement (DI state) is not reliable
7,3 V AI protection voltage reference. If the voltage differs from the limit values, the AI measurement is not reliable
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Symbol |
Parameter |
Conditions |
Min |
Max |
Units |
|
UR3V6 |
Nominal 3,6 V DI threshold voltage level |
|
Typ. 3,6 |
V |
|
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3,4 |
3,8 |
V |
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UR7V3 |
Nominal 7,3 V AI protection voltage level |
Typ. 7,3 |
V |
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|
6,8 |
7,8 |
V |
|||
|
Diagnostics |
Low |
High |
Units |
||
|
|
Recommended DI threshold voltage warning levels |
|
3,4 |
3,8 |
V |
|
|
Recommended AI protection voltage warning levels |
|
6,8 |
7,8 |
V |
Equations for internal voltages:
3,6 V:
U [V] = ADCvalue * (5 V / 1023)
ADCvalue = Last written value from ADC
7,3 V:
U [V] = ADCvalue * (10 V / 1023)
ADCvalue = Last written value from ADC
For measurement details, refer to Epec 4602 technical document.
Equation for temperature:
T [0,1°C] = (5096 * ADCvalue) / 1000 - 2209
ADCvalue = Last written value from ADC
For interface addresses, refer to section PLCopen Addresses
Use library function ADC_To_Ohm (FUN) (in library ADConversion)
Use input i_ADCValue for input voltage measurement
Use input i_ReferenceADCValue for pull-up voltage measurement
Source file topic000750.htm
Last updated 4-Sep-2025
