Example of the calculation of cycle times of a MAST task under the following conditions

Context

An application with the following characteristics:

TSX P57 204 processor,
Execution of a program in PLC internal RAM,
10 K instructions: 65% Boolean + 35% digital,
a communication EF of the type SEND_REQ (for a TSX PSX 204 the execution time is 0.75 ms),
128 discrete inputs distributed over 7 TSX DEY 16D2 modules + 1 TSX DEY 16FK module,
80 discrete outputs, distributed over 5 TSX DSY 16T2 modules,
32 analog inputs, distributed over 2 TSX AEY 1600 modules,
16 analog inputs, distributed over 4 TSX ASY 410 modules,
2 upcounting channels, distributed over 1 TSX CTY 2A module.

Calculation of the different times

Application code execution time (APCET):

Overhead system time (Ost) = 1ms

Input and output management time for implicit I/O %I and %Q:

Module product references	Module type	Number of modules	Input management time (IN)	Output management time (OUT)
TSX DEY 16D2	16 channel discrete inputs	7	189 micro seconds	-
TSX DEY 16 FK	16 channel discrete inputs (fast inputs)	1	37 micro seconds	22 micro seconds
TSX DSY 16T2	16 channel discrete outputs	5	165 micro seconds	100 micro seconds
TSX AEY 1600	Analog inputs	2 (32 channels)	672 micro seconds	-
TSX ASY 410	Analog outputs	4 (16 channels)	236 micro seconds	236 micro seconds
TSX CTY 2A	Counting	1 (2 channels)	110 micro seconds	40 micro seconds
Total management time			1409 micro seconds	398 micro seconds

Input management time: Imt%I = 60 microseconds +1409 microseconds = 1469 microseconds = 1.47 ms.

Output management time: Omt%Q = 60 microseconds +398 microseconds = 458 microseconds = 0.46 ms.

Communication system time:

Cycle time without execution of the communication OF

TcyM = Apcet + Most + Imt%I + Omt%Q

= 2.8 ms +1 ms +1.47 ms + 0.46 ms = 5.73 ms

Cycle time with execution of the communication OF and sending of the request

TcyM = Apcet + Most + Imt%I + max [request send time (scomT), Omt%Q]

= 3.55 ms + 1 ms + 1.47 ms + max [1.5 ms; 0.46 ms] = 7.52 ms

Cycle time with reception of reply

TcyM = Apcet + Most + max [response send time (scomT), Tge%I] + Omt%Q

= 2.8 ms + 1 ms + max [1.5 ms; 1.47 ms] + 0.46 ms = 5.76 ms