Configuration Example: 32-Bit Forward Counter

All of the 8 channels of the DC541-CM can be used as count-up counter. In the configuration example, all 8 channels of the DC541-CM are configured as 32 bit forward counter (count-up). The channels C0…C3 operate as infinite counters (endless mode), the channels C4…C7 as limit counters (limit mode).

The 32 bit count-up counter configured as infinite counter (endless mode) corresponds to mode 1 (1 Up counter) of the high-speed counter of the digital input/output modules. In the configuration example, the counting pulses for the first forward counter are therefore applied in parallel to input C0 of the DC541-CM and counting input C24 of the DC532.

Hardware configuration

The example control system shall have the following configuration:

• Terminal base TB521 (two Communication Module slots)
• DC541-CM in Communication Module slot 1 (first slot on the left of the CPU)
• PM591-ETH CPU with internal ETHERNET Communication Module
• I/O module DC532 on the I/O bus

Wiring

The channels are connected as follows:

• DC532 / C16 ————– DC541 / C0
• DC532 / C17 ————– DC541 / C1
• DC532 / C18 ————– DC541 / C2
• DC532 / C19 ————– DC541 / C3
• DC532 / C20 ————– DC541 / C4
• DC532 / C21 ————– DC541 / C5
• DC532 / C22 ————– DC541 / C6
• DC532 / C23 ————– DC541 / C7
• DC532 / C16 ————– DC532 / C24

PLC configuration

• DC541-CM in slot 1, operating mode “Counter mode”
• Configuration: - Channel   C0..C7   Forward counter
• Specification of the ETHERNET Communication Module as internal Communication Module (if available)
• DC532 on the I/O bus / parameter “Fast counter” = 1-1 Up counter

Task configuration

• Task 1: Cyclic program / Prio = 10 / Interval = t#100ms / PLC_PRG
• Task 2: Simulation / Prio = 15 / Interval = t#5ms / Simulation_Task

The cyclic program PLC_PRG contains the following functions:

• Reading the cycle of PLC_PRG Calling of block TASK_INFO;
• Reading the configuration of the DC541 Calling of block DC541_GET_CFG
• Reading the status of the DC541 Calling of block DC541_STATE
• Reading/writing the static channels of the DC541 Calling of block DC541_IO
• Calling of the sequence control for the counters Calling of program proForwardCounter

The blocks DC541_GET_CFG, DC541_STATE and DC541_IO are contained in the library DC541_AC500_V11.lib and described in detail in the library documentation DC541_Library: DC541 Library

The block TASK_INFO is contained in the library SysInt_AC500_V1.0 SysInt_Library: Internal System Library

The actual execution of the 32 bit forward counter functionality is implemented in the program proForwardCounter.

Purpose of the program proForwardCounter:

The program proForwardCounter executes the following step chain:

Counter block	DC541_FWD_CNT CNT_IO								CNT_IO
Step | Channel	C0	C1	C2	C3	C4	C5	C6	C7	1
0 | Action	Init: SET = 0, endless counter, limit values MIN = 300 / MAX = 1300				Init: SET = 0, limit counter, limit values MIN = 300 / MAX = 1300				Init
|   Value	0	0	0	0	0	0	0	0	0
1 | Action	Reset of SET input
|   Value	0	0	0	0	300	300	300	300	0
2 | Action	Start of pulse output - 2000 pulses
|   Value	0	0	0	0	300	300	300	300	0
3 | Action	Wait until pulse output is completed
|   Value	2000	1000	500	250	1299	1300	800	550	2000
4 | Action	Selection last step: byStep = 249
|   Value	2000	1000	500	250	1299	1300	800	550	2000
200 | Action	Manual operation
|   Value	xxx	xxx	xxx	xxx	xxx	xxx	xxx	xxx	xxx
249 | Action	Wait time 5 seconds, then restart from step 0
|   Value	2000	1000	500	250	1299	1300	800	550	2000

The block Simu_Pulse is used to generate an adjustable number of pulses. Its representation in the function block diagram (FBD) is as follows:

Instance		fbSimuPulse	Instance name
Ben	Input/Output	BOOL	Enabling of the pulse output
bReset	Input/Output	BOOL	TRUE = Reset of the pulse counter, bDone = TRUE
bAutoReset	Input/Output	BOOL	TRUE and cyclic mode - The time tResetTime is started when the number of pulses set with dwPulse is reached. After this time, the pulse output is restarted again.
tResetTime	Input/Output	TIME	Wait time until restart, if bAutoReset = TRUE
dwPulse	Input/Output	DWORD	Number of pulses to be output: = 0: Endless mode (pulse output continues until bEn = FALSE or bReset = TRUE) > 0: Cyclic mode (output of the specified number of pulses)
Bdone	Output	BOOL	Completion message after the number of pulses specified at dwPulse or after bReset if dwPulse = 0
bToggle_0	Output	BOOL	Output: Edge with each clock cycle
bToggle_1	Output	BOOL	Output: Edge with each 2. clock cycle
bToggle_2	Output	BOOL	Output: Edge with each 4. clock cycle
bToggle_3	Output	BOOL	Output: Edge with each 8. clock cycle
dwActNumPulse	Output	DWORD	Number of pulses output
tActTime	Output	TIME	Elapsed time in [ms] while tResetTime is running

In the example, the block Simu_Pulse is called in a 5 ms task. The pulse output is enabled or stopped via input bEn. If input dwPulse = 0, the output of pulses is performed continuously. If dwPulse > 0, only the specified number of pulses is output. When the specified number of pulses is reached, output bDone is set to TRUE.

In the example, the block is called with dwPulse = 2000. The wait time function is not used.

The example program has a visualization implemented that displays all states:

Clicking on the button <Enable visu control> (bEnVisuControl = TRUE) causes the program to jump from the current step to step 200 (manual operation). Then, the operation of the blocks is done via the corresponding pushbuttons/switches of the individual blocks. When manual operation is switched off again (bEnVisuControl = FALSE), the program jumps to step 249 and restarts from step 0 after the wait time.