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Using the timer block, 5 using the timer block – Micromod MOD: 1800P - MOD 30ML Identity Module (Version 2) Algorithms, Tables and Sequential Logic Functions User Manual

Page 69

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Logic Functions - Book 2

TIMER BLOCK

8-61

8.7.5

Using the Timer Block

The following examples show some typical uses of a timer block.

EXAMPLE 1 Self Resetting Timer (Figure 8-32)

Timer starts timing, time out, reset, starts timing, reset, etc. This cyclic operation provides
regular pulses for use by other function blocks and to field devices via a digital output module
block. The period of the waveform created by this example is the reset input/limit difference
value plus one task scan cycle. The extra task scan cycle is the reset cycle time.

RESINP

HLSTAT

TM1

Reset Input

High Limit Status

Discrete Output to
Another Function Block

Requires No
Initiating Logic

Figure 8-32. Softwiring Drawing for Timer Block, Example 1

EXAMPLE 2 Timer Held Inoperative by Maintained Reset Source (Figure 8-33)

Timer will not start timing until reset source makes a true to false transition. Timer will then
time from reset input value to its limit.

Initiating

Logic

RESINP

Discrete Output

HLSTAT

TM2

Reset

High Limit Status

Discrete Output to
Another Function Block

R

EX1

Equation

Result

Disable Input

DISINP

Figure 8-33. Softwiring Drawing for Timer Block, Example 2