Endress+Hauser Liquiline CM44P - Page 106

Operation Liquiline CM44P
106 Endress+Hauser
T
[° C]
t [h]
18
21
23
8
12 17
0
T2
T1
A0041704
 91 Time-based temperature control
1. Program Time switch 1 (T1):
• Start date = 01.01.2020
• Start time = 08:00:00
• Signal duration = 09:00:00
• Period = 24:00:00
2. Define Time switch 2 (T2):
• Start date = 01.01.2020
• Start time = 12:00:00
• Signal duration = 05:00:00
• Period = 24:00:00
3. Create Formula mathematical function.
Menu/Setup/Additional functions/Mathematical functions
• MF1: Formula
• Tracking = On
• Source A = Time switch 1
• Source B = Time switch 2
• Formula = 18.0 + 3*NUM(A) + 2*NUM(B)
Explanation: NUM converts the logical value to a numerical value and thus enables
multiplication.
• 3*NUM(A) results in the value 3.0 from 08:00 to 17:00 and 0.0 outside of this time
period.
• 2*NUM(B) results in the value 2.0 from 12:00 to 17:00 and 0.0 outside of this time
period.
The formula thus yields one of these analog values depending on the time: 18.0, 21.0 or
23.0. This analog value can be used as a set point for a temperature controller.
Example 2: Time-based condition
A pump should switch on (via a relay) for 10 minutes every 2 hours. This only applies if
the pH value is lower than 4.0.
1. Program Time switch 1:
• Start date = 01.01.2020
• Start time = 00:00:00
• Signal duration = 00:10:00
• Period = 02:00:00
2. Create Formula mathematical function.