Counters
- Last UpdatedJul 03, 2020
- 1 minute read
The following table summarizes data format, item or point, suffix, data type, and range for Counters.
|
Data Format |
Item/Point |
Suffix |
Data Type |
Range |
|
Word |
Cx Zx |
None None BCD KT S5T |
VT_UI2 VT_UI2 VT_UI2 VT_BSTR VT_BSTR |
0…65535 0 to 65535 0 to 9999 0.0 to 999.3 0ms to 2h46m30s |
Where:
|
x |
is the start address, with a range from 0 to 65535. |
When the suffix is used, the client is responsible for ensuring the correct value is specified or returned.
Note: S7-1200 and S7-1500 PLCs do not support "direct" counter\timer access by the client/server. That is, you cannot use the current S7-300/400 item name Cx or Tx and its associated suffixes to subscribe to counter\timer values from the S7-1200 and S7-1500 PLCs. However, you can use the database items to indirectly output the associated system counter\timer value (internal IEC counter\timer) from the PLC.
For example:
If the value of counter C0 is 42, the value read by just using the "C0" item syntax is 42. However, if the item syntax is "C0 BCD," the value returned by the Communication Driver is 66.
A similar principle applies to poking:
If the value for the counter is 42, using the "C0" pokes a value of 42 into the counter C0. However, with the "C0 BCD" syntax, the poke value is 66.
Note: All counters are Read/Write. The Communication Driver processes a write (POKE) to a counter. Although the Communication Driver allows poking any word value into counters, the S7 PLC can only process values in the range of 0…2457 or 0…999 (BCD).