FC 102 - Pulse Input / Period

The pulse input/period function code interfaces a controller to a selected channel of an IMDSM04 pulse input I/O module.  The IMDSM04 module conditions, converts and processes pulse inputs into analog signals. It has eight input channels whose inputs can be processed in three modes: period, frequency or totalization. Function code 102 processes a signal in the period mode. Function codes 103 and 104 process signals in the frequency and totalization modes, respectively. Function code 109 processes the duration of the input pulses. Each input channel must have one and only one pulse input block configured.

 

 

Outputs:

Blk

Type

Description

N

R

Period (seconds) X gain

N+1

B

Period high alarm:

0 = no alarm

1 = high alarm

N+2

B

Period low alarm:

0 = no alarm

1 = low alarm

N+3

B

I/O module communication status:

0 = good

1 = bad

 

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

0

I

0 - 63

Expander bus I/O module address of IMDSM04

S2

N

1

I

1 - 8

Selected channel

S3

N

0

B

0 or 1

Pulse trigger level:

0 = low to high transitions

1 = high to low transitions

S4

N

1

I

1 - 6

Expected period range:

1 = 0.1 msec - 6.553 secs, + 0.1 msec

2 = 1.0 msec - 65.53 secs, + 1.0 msec

3 = 10.0 msecs - 655.3 secs, + 10.0 msecs

4 = 0.1 sec - 6.553 ksecs, + 0.1 sec

5 = 1.0 sec - 65.53 ksecs, + 1.0 sec

6 = 10.0 secs -1 655.3 ksecs, + 10.0 secs

S5

Y

1.000

R

Full

Gain

S6

Y

9.2E18

R

Full

High Alarm Value

S7

Y

-9.2E18

R

Full

Low Alarm Value

S8

Y

0.000

R

Full

Spare

 

 

102.1  Explanation

 

In the period mode, a counter measures the time between input pulses. Specification S4 configures the expected period range. There are six ranges available with range one having the highest resolution and range six having the lowest resolution. The pulse trigger transition can be configured to respond to either the rising or falling portion of the signal with S3. Specification S5 scales the determined period. The determined period is tested against specified high (S6) and low (S7) alarm values.

 

102.1.1  Specifications

 

S1 - SLVADR

Expander bus I/O module address of the IMDSM04 module. Valid addresses are zero to 63.

 

S2 - CHNL

Identifies the input channel being monitored. IMDSM04 modules have eight input channels. Refer to the IMDSM04 Pulse

Input Module product instruction to identify the channel associated with each input.

 

S3 - PTRIG

Defines the type of signal transition that triggers the counter response.

0 = response on low to high transitions

1 = response on high to low transitions

 

S4 - RANGE

Defines the range within which the period of the input pulse is expected to fall. There are six period ranges. Resolution

decreases from range one to six.

1 = 0.1 millisecond to 6.553 seconds, + 0.1 millisecond

2 = 1.0 millisecond to 65.53 seconds, + 1.0 millisecond

3 = 10.0 milliseconds to 655.3 seconds, + 10.0 milliseconds

4 = 0.1 second to 6.553 kiloseconds, + 0.1 second

5 = 1.0 second to 65.53 kiloseconds, + 1.0 second

6 = 10.0 seconds to 655.3 kiloseconds, + 10.0 seconds

 

NOTES:

  1. If the period of the input pulse becomes larger than the expected range, output N goes to zero. This can be used to indicate a loss of input signal.

  2. If the input pulse becomes smaller than the expected range, the output oscillates between 0.0 and the smallest measurable period for the selected range.

 

S5 - K

Defines the gain multiplier. The gain multiplier is the value used to scale the output to a value that is meaningful to the system.

 

S6 - HALRM

Value of the output that causes the high alarm output to go to one. Specification S6 is dependent on the values chosen with S4 and S5.

Output = period(gain)

 

S7 - LALRM

Value of the output that causes the low alarm output to go to one. Specification S7 is dependent on the values chosen with S4 and S5.

Output = period(gain)

 

S8

Reserved.

 

 

102.1.2  Outputs

 

N

Real value representing the period (in seconds) times the gain.

 

NOTES:

  1. If the period of the input pulse becomes larger than the expected range, output N goes to zero. This can be used to indicate a loss of input signal.

  2. If the input pulse becomes smaller than the expected range, the output oscillates between 0.0 and the smallest measurable period for the selected range.

 

N+1

High alarm indicator.

0 = no alarm

1 = high alarm

 

N+2

Low alarm indicator.

0 = no alarm

1 = low alarm

 

N+3

I/O module communication status.

0 = good

1 = bad

 

I/O modules are bad if:

• There is an illegal I/O module response.

• There is no I/O module response.

or

• An input pulse has not been received.