The dataTaker data loggers have three high speed counters, which are available as separate input channels from the low speed counters.

The high speed counters are able to count at up to 1 KHz or 1MHz, and may be used as accumulating counters or as resetting counters.

The Channel Expansion Module (CEM-AD) does not have high speed counters.

The high speed counters of the dataTaker can be used to count digital pulses in either of two modes

as accumulating counters, which totalise the pulses forever. When accumulating counters are read, the current contents of the counter registers are returned

as resetting counters, which totalise pulses between readings. When resetting counters are read, the current contents of the counter registers are returned, and the register is reset to zero

Individual counters cannot be simultaneously used as accumulating and resetting countersñ if you need total and interval counts, then input the same pulse train into two channels, and run one as an accumulating counter and the other as a resetting counter.

The high speed counters are 16 bit up counters, and have a count range of 0 to 65535. The counters begin at zero counts, count up to 65535, 'roll over' to 0 on the next count, and then continue to count upwards.

The high speed counters increment when the state of the digital input switches from high (logic 1) to low (logic 0).

The circuit function schematic for the three high speed counter channels is illustrated below

 

 

Figure 119 ñ The High Speed Counters

 

The high speed counters are normally able to count at up to 1 KHz. However the counters can be modified to increase the frequency to 1MHz by removing filtering capacitors from the counter input. Your dataTaker supplier can carry out this modification if required.

Low Power Mode

The high speed counters are hardware counters, in contrast to the low speed counters which are software counters.

The high speed counters continue to register counts while the dataTaker is in the low power mode. However the logger can only return high speed counter data while the logger is awake. The maximum count rate decreases while the logger is asleep.

Connecting High Speed Counter Inputs

The high speed count inputs are connected to the high speed counters between the selected counter channel terminal, and any GND or unused Analog Return terminal as follows

 

 

Figure 120 ñ Connecting a High Speed Count Signal

 

Reading as Accumulating Counters

The high speed counters are operated as accumulating counters and the count data is returned to the host when a Schedule containing the channel is executed. The counter is not reset.

Using DeTransfer, the command for example

instructs the dataTaker to read the current values for the high speed counter channels 1 and 2.

The HSC specifies an accumulating high speed counter.

Using DeLogger, the high speed counters can be read as accumulating counters by the following Program Builder program. The accumulating counter mode is selected directly from the channel selection walking menu.

 

 

The data is returned in units of Counts.

The dataTaker will read the counters every 5 minutes, and readings are stopped by the H (Halt) command.

Reading as Resetting Counters

The high speed counters are operated as resetting counters, and the count data is returned to the host, when a Schedule containing the channel is executed. The counter is reset each time that it is read.

Using DeTransfer, the command for example

instructs the dataTaker to read the current values for the high speed counter channels 1 and 2, then reset the counters.

The HSC specifies an accumulating high speed counter. The R channel option specifies that the counter is to be reset to zero when read.

Using DeLogger, the high speed counters can be read as resetting counters by the following Program Builder program. The resetting counter mode is selected directly from the channel selection walking menu.

 

 

The data is returned in units of Counts.

The dataTaker will read the counters every 5 minutes, and readings are stopped by the H (Halt) command.

Programming of the high speed counters is described in detail in Section III ñThe Counter Channels.